2020

Print this entry

This evergreen tree grows up to around 15 feet.  It has a big buttress and short stubby roots which hold great amounts of water, thus a drought resistant tree.  The nut has a hard shell and splits open when ripe, releasing around 15 fingernail size seeds.  If the seeds are soaked overnight in water they will split and begin to germinate like a bean but with two compressed leaves already formed.  These germinating seedlings can be eaten raw or lightly cooked/fried in combination with other dishes of one’s own choice.  They are among the best nuts in terms of flavour and taste.

A grafted tree will bear fruit around 2 years and seedlings within 5 years.  In some African countries, the tree is grown commercially for making flour from the nuts.  This will be a good substitute for people intolerant to eating wheat flour products. Because the plant needs little water to survive and the flowers are highly scented, this tree is widely treasured as a gift plant and as a bonsai in Taiwan and Japan.

Sourced from: 

Print this entry

On a recent visit to South Australia I caught up with Ian Tolley who taught production horticulture to visiting Ag.Sc. students from the University of Adelaide, Waite Campus for more than 40 years. He travels extensively overseas as a consultant/trouble shooter advising governments and industry on Citrus within a framework of Horticulture. In 1965 he was awarded a Churchill Fellowship in Citriculture. He also has an ABC gardening session every 6 weeks. In 1995 he was awarded an Order of Australia Medal for services to the community, horticulture and the citrus industry and with Bruce Morphett has written for the SA Botanic Gardens an illustrated handbook called Citrus for Everyone.

Citrus in Pots

Ian:   For terracotta pots there’s an excellent product out in a spray pack called Terra-Shield. You can clean the inside of the pot with stainless steel wool before you use it and spray it 2 or 3 times. It won’t allow the magnesia to seep out and make the pots look awful – it’ll make them waterproof and it’s permanent. It’s a methyl silicone compound so it really lasts.

Sheryl:    I have some very large ceramic pots I was thinking of putting some citrus in, but don’t like the idea of having to repot every so often. I was thinking of painting on something to burn off the roots when they touch the sides.

Ian:    You’re talking about Spinout but what will happen is that when the roots touch the sides they will just go round and round.

Sheryl:    It will become root bound!

Ian:   Undoubtedly, but it won’t cause the tree a moment’s worry in the pot. It has never been told that root bound is bad – it has never been told that shaping trees is good. It’s only when you get out into the orchard and you’ve got a pot bound tree grown in a small bag. If you plant it like that, it may never get established and when the first wind that comes along then there’s a problem.

If you want to use wine tubs then you should prepare them for long term use before planting. Use raw linseed oil and soak them with several applications because it tightens up the boards and makes them waterproof.  If you’re really worried, then line the sides with 6mm black plastic. Make sure you’ve got several big auger holes in the bottom, one inch (25mm) in diameter. Use shade-cloth to cover the bottom. This will allow water to drain out of the auger holes but not the potting media. Sit the tub on two 3”x2” (7.5 x 5cm) hardwood timber bearers as level bases. Drainage will never be a problem and the barrel will last for decades. Now you can check that only a little water leaches out the drainage holes and not a drop more, saving fertiliser loss by leaching.

Sheryl:   So I don’t have to repot every couple of years?

Ian:   No – some of my citrus in tubs have been in the same substrate for 20 years but you must buy potting media that has the 5 ticks on the container. These are ASK Australian Standard requirements. Basically it should have a pH5.5 to 6.5 and an air filled porosity (AFP) of 25%. Some mixes have fertilisers added to the substrate and are then usually labelled as ‘citrus mix’.

Sheryl:  What do you think are the best varieties to go into pots?

Ian:   In principle all citrus species grow well in pots. The larger the fruit, the bigger the pot should be. All need to be shaped to maintain a compact shape producing many short but fruitful spurs. It is the way for even crop production and manipulation.

Propagation Mix

Use builder’s sand, washed and cleaned to cover seed for germination, using standard potting media as the substrate. Kevin Handreck in Adelaide is a fellow member of the International Plant Propagator’s Society (IPPS) – his book ‘Growing Media for Ornamental Plants and Turf’ is the plant grower’s bible and you must have it as a reference. He has revised and enlarged his 1984 original, now third edition published in 2002.  (ISBN 0 86840 796 8.)  The balance of the media is fertiliser and there are many forms. I tend to use organic types – Neutrog & Easy-Grow, both of which use compressed pelleted chicken manure bases. They are slow release and provide the bulk of the NPK segment, but both have micro-elements. I apply an annual dressing in spring over the garden for a very wide range of plants. For pots, unless they are very large, these fertilisers tend to overfill the space normally allowed for watering. An improved way for home gardeners with smaller containers is to try using Seasol on a regular fortnightly schedule as liquid feed. It contains growth stimulants and is not a fertiliser on its own. Include their Powerfeed to provide nutrients and the combination is easy to use.

Book Reference

Sheryl:   Louis Glowinski in Melbourne says that the editors just won’t do any corrections when reprinting his book.

Ian: I edited the Citrus section of Louis’ book “The Complete Book of Fruit Growing in Australia” at his request. He told me also of the publisher’s reluctance to amend the text. I know he is unhappy about it but in general, it is an excellent reference book.  

Rootstock influence

Let me dispel a myth about rootstocks in pots. Potted plants automatically develop root growth to fill the pot so even on this ‘blasted’ Swingle citrumelo (and don’t edit ‘blasted’ out!) you could put that in a pot and it would do fine. Any rootstock is suitable providing the potting media meets the criteria I’ve mentioned. There is a nursery in Northern California that says ‘we are using a special citron dwarfing rootstock and have done for many generations’. This is a load of codswallop because any rootstock will do in a pot because the pot ultimately restricts the root ball and limits the top growth! If you use slow growing rootstocks like the deciduous Poncirus trifoliata [it grows the best quality fruit as well as its dwarfing mutation P.trifoliata var. monstrosa (flying dragon.)] So if you wanted superb quality fruit – internal and external, these rootstocks impart a cold tolerance which is fantastic in the lower cooler areas of Australia. In the tropics they will slow rank growth. You will get prolific precocious cropping from both and they are resistant to nematodes and phytophthora.

Seedling or cutting grown Citrus

If you should want to try this then they should only be grown in pots as they may be affected by phytophthora parasitica in tropical/sub-tropical climates or phytophthora citrophthora in temperate climates if grown in soil.

Rootstocks

I’ve spent over 40 years studying and trialling citrus rootstocks and rootstock/scion interactions. Cleopatra mandarin rootstock produces good quality fruit – it’s great on alkaline (pH10) soils. It can be slow growing and a little bit of a light cropper to start with but once it settles in, it’s OK. For Broken Hill or other similar limestone areas this would be one of the few that would cope in such harsh conditions. For you in sub-tropical to tropical areas it grows well. It is mildly tolerant to phytophthora and nematodes, but as for many citrus rootstocks, mounding will avoid wet feet in heavy rainfall periods.

Cross-Pollination induces more seediness in Citrus

40 years ago I imported a tangelo group from California. All are Dancy mandarin x Duncan Grapefruit. Orlando,(early) Minneola,(mid-season) and Seminole.(late maturing.) We were told they won’t crop unless you cross pollinate them. We went to no end of trouble with Lemons and Valencias to get cross-pollination. I can tell you that Orlando can produce 50 seeds and outdo Murcott anytime! Minneola were somewhat the same with 30-40 seeds and that was unsettling. Seminole we could get up to 60-80 seeds, so I began to query this ‘fact’. The Californians still said that this was the way to go. We were able to produce good sized crops with much less seed when grown in areas more isolated from other pollinators. So this was an exercise in ‘don’t accept all you are told’ but do your own trials in your own environment if you are not certain. Some years later, we found more real facts from the work done by Dr. Anna Kultinow at Waite Institute Campus of CSIRO into developing seedless mandarins (refer to my book). Seedlessness affects fruit size so some varieties that are normally a good size if you do not pollinate them (e.g. cover them with bee proof netting) and not get any pollination, the fruit size drops to a stage where it is no longer commercially practical. Seedless Valencias seldom get to large size because they don’t have seeds so if you have 3-5 seeds you get reasonable size Valencias.

From a pollination point of view in mandarins, you have to determine if it has a propensity for over-pollination and therefore extreme seediness like the Murcott. Now we have a bind that Dr. Koultinow is in the middle of where she can’t go any further. By saying ‘if I give you a Murcott that is absolutely seedless, I can’t guarantee you large fruit size’. There is a trade-off in pollination of citrus cultivars right through that we would like to have the best of all possible worlds.

The summary of what I observe currently is this: that we need a little pollination for the varieties of which we speak in the mandarin and mandarin hybrids. Minneola, Orlando and Seminole are mandarin hybrids, all of those are Dancy Mandarin crossed. (note: I didn’t say Tangarine because that word is an American sales ploy.)

So we need to put up with some seed and enjoy some superb varieties particularly Minneola provided you leave until ripe on the tree. If you try and market it with a glossy skin – firm, tight, packable it’s as sour as any lemon you will ever grow. These are some of the trade-offs with some varieties.

There’s a new variety, Daisy, but if you have Black Spot in your area you could have a really good collection of spores if you’re a Pathologist! (Lovely fruit – lousy growing) In Morocco they grow seedless Clementines on large orchards over 500 acres where they don’t get cross-pollinated. All the new varieties are aiming for as little seed as possible, as resistant to fungal diseases as possible, easily peelable, good colour and preferably with regular cropping. If you do get alternate bearing, this can be solved by pruning and tree shaping following the off-crop year. All citrus fruit is born on terminals. Reducing terminals AFTER a light crop reduces the following crop from heavy to moderate but larger fruit. Kara is the latest maturing mandarin, easy to peel and excellent flavour. It does have a few bumps on the skin so it’s not saleable in the marketplace, but is an excellent fruit for the home garden.

Correct Pronunciation and Identity

Sheryl:    What is the correct way to pronounce:

Persimmon     

Pers-immon. (Per-simmon is the American pronunciation)

Tangelo          

Tang-elo with the emphasis on the first syllable – not Tan-gelo (only one l also)

Poorman

Pomelo is pronounced Pomelo and that name is often used instead of its proper name of Poorman. It’s great for breakfast. The tree is easy to grow and a consistent cropper. The fruit hangs on the tree much longer than the common white fleshed Marsh grapefruit. Poorman (or Pomelo) has very few seeds, dark flesh, very juicy, when you eat it you think – I’m drowning in this! and when you finish you say – in my mouth I have a beautiful grapefruit aftertaste which you don’t get in the Pummelo family. Poorman is thought to be an Orange x Seville hybrid first recorded in Australia as early as 1820. New Zealand introduced it in 1855 because it has a low heat requirement. They renamed it New Zealand grapefruit, and latterly Goldfruit. They can’t grow true grapefruit in NZ because of their cold climate. (low heat units)  We have a Smooth Red Seville (looks like a red grapefruit) that is an Australian mutation of the common rough (yellow) Seville. It is sour but good for marmalade. These two are NOT related to the Pummelo (citrus maxima) family

Pummelo        

Pronounced Pum-melo, looks like a flattened Grapefruit – usually very large, somewhat seedy (like Wheeny grapefruit) To flourish, they need very high numbers of heat units so they only grow well in the real tropics. Thailand has six cultivars covering the full year of cropping at maturity.

Citrus grandis decumana (a Pummelo selection of unknown origin)

It has no common name – butter yellow, the fruit is very small here now because you can see the (very low) bud union physiological incompatibility. Whilst I have inarched to save the tree and there are more suckers, so I can then put more inarches to separate limbs. You can see that the suckers have come from the rootstock indicating a (bud union) restriction and reducing the fruit size from head size when we first got it and now it’s a miserable specimen with very thick skin. A high 35cm budding or better still, grafting, would have solved this problem by producing a smooth union.

Pummelos are used extensively in Thailand and neighbouring tropical countries but they have many better cultivars than this one. They cut the skin in 1” strips, scrape away the white pith, soak the skin in a saturated sugar solution for 48 hours, The dried slices are chopped into 1” squares put on racks to dry and that’s their sweetmeat – their lollies! It’s very nice. This cultivar has a very distinctive, highly ribbed leaf. The Pummelos in general have large, very smooth leaves and a round shape.

Sheryl:  It tastes very mild and not at all tart.

Grapefruit 

This is Star Ruby – I imported the first lot in as seed from the US Citrus and Date Station at Weslaco in Texas. This is one of the original red grapefruit, products from   irradiation of Marsh Grapefruit. The yellow splotches on the leaves are the result of sunburn toxicity. In southern California on subsequent visits, I found they grow them under date trees and they don’t show this problem at all – they just don’t like direct sunlight and it’s a deficiency caused by genetic changes through the irradiation. Star Ruby is one of the best. Ray Ruby, Rio Red are other selections but they are all seedling selections from the original experiment.

Chironje (pronounced cheer–own-aa)

Sheryl:  This is fantastic – just superb.

Ian:  It’s a chance hybrid that’s been known in Puerto Rico for hundreds of years and was found in the forest by American botanical explorers in the 1800’s and sent to Washington and then to California. I’ve been growing it for 30 years and I still think it is one of the best of the non-mainline varieties. It holds its fruit on the tree, doesn’t granulate, keeps its juice and what you are eating is fruit from last year. It’s a cross between an Orange and a Grapefruit. The researchers in California have established that but their parents have been lost in antiquity. They haven’t been able to trace it in Puerto Rico other than to say that there are a whole lot of grapefruit and oranges around and there’s a mixture of everything but they can’t put it down to two in particular. The industry is now beginning to do DNA testing. If anyone is really interested then one could do something about identity in the future.

Limes

Palestine Sweet Lime

Taste is like Barley water, no acid. Used for generations as a rootstock in the Middle East until improved virus testing procedures put it out of contention. Grown on Troyer Citrange rootstock – A myth: some industry people keep on saying Troyer Citrange is different to Carrizo Citrange – they are both the same. Any differences are the result of seedling variation as they are not 100% genetically true-to-type. I have the US chart to confirm their true origin and I am happy to provide it.

Kusaie

The yellow fruited form (mutation) of Rangpur, and of Indian origin. It leaves Tahitian Lime for dead. Kusaie produces much smaller fruit year round (the fruit stays on the tree) whereas in temperate climates, the tropical Tahitian produces only one crop and then sheds it. 

Rangpur

A dark orange colour – larger fruit than Kusaie. It has a nipple on the bottom to identify the clone, and also crops year round. The reason I like them both is because they are hybrids and believed to have mandarin in their background. This gives them cold tolerance and the ability to react to changing conditions including shaping so that they can flower and fruit all year round. I think they make some of the best patio specimens and useful too.

Citrus hystrix

A prized fruit (very bumpy skin) in Thailand. The women have the most gorgeous black flowing hair. When their children go to school they can get lice in their hair. If you grate the fruit, it makes instant shampoo in water. It foams up, has a beautiful smell, kills the lice and keeps their hair in beautiful condition, as it is a natural insecticide. The leaves are used in infusions for tea etc. It depends where it is grown as to whether the leaves retain that strong characteristic. The tropics are the best climate. Some people kid themselves when they grow it in cool climates, do their infusions and think it is nice, but the reality is different.

Sheryl:   This is what we call Kaffir Lime? 

Ian:  Wrong name! There is no mention in any respected citrus journal of Kaffir. It is widely known in Asia as Makrut lime. I was repeatedly told that name over the four years I consulted in Thailand. 

Blood Lime  

It’s a CSIRO hybrid developed at Merbein, Victoria and patented. It has been made available to contracted growers only.

West Indian Lime   

It’s a little seedy but it’s the most acid lime that you can grow. It is propagated by seed, but it tends to suffer from Tristeza virus – my particular cultivar was selected for its resistance. If you don’t have a high aphid population, you can get away with growing it from seed.

Wild Tangerine? or Wild Lime?

Sheryl:  aaaaah!!!! very sour

Ian: I think it came from Indonesia many hundreds of years ago. It has a sharp lime flavour and is a good cropper. NT aborigines know about it – tends to be a little thorny but after a while you’ll notice in a few years, up at the top, some branches that are not too thorny. You can breed much of the thorniness out of citrus by using that observation. The further you are away from the original cell subdivision, the less thorns or juvenile vigour.  Just take thornless buds or a small thornless graft from the tip of the plant and grow it on for several years more and you’ll finish up with very few thorns.

Rootstock Issues

Ian: These trees are on Flying Dragon rootstock and they’re all budded or grafted to Marumi Cumquat.  We also use Flying Dragon as a rootstock for dwarfing trees in the field. It will tolerate a wide range of soil conditions even up to pH9 so long as there is very good drainage. In containers there is a need to stay in the range of pH5.5 – 6.5 to obtain the best nutrient availability. We have a Flying Dragon seed production planting in macropots. We use Flying Dragon rootstock for almost everything for home gardeners, providing we know the proposed budline is free of Exocortis viroid.

Sheryl:  It looks like Flying Dragon would be excellent as a bonsai. When wouldn’t you use Flying Dragon as a rootstock?

Ian:  Lemons – that’s the only one – the only compatible exception that is OK is Prior nucellar (means virus free) Lisbon.  It’s an American cultivar and we had two – Prior and Monroe. When I did the field testing on Monroe, after 10 years I found it had exocortus viroid and had to scrub it. There were no reliable heat treatment facilities at that time. I don’t like Swingle Citrumelo – it’s a terrible rootstock. From a home gardener’s point of view, if I said to you: Do you want something very vigorous, grows to 10 metres, produces coarse fruit and doesn’t like limey areas? No thanks! They use it in Florida because they have a decline problem called Citrus Blight. This rootstock is resistant and it’s the only way they can keep growing citrus in the affected areas. There is an area in the Burnett Valley in Qld. that’s in quarantine due to it being (illegally!) introduced to Australia on infected budwood so hopefully it will stay there. It is not yet possible to destroy the organism.

Pest management 

We use the systemic Confidor, mainly for Mealybug, once every 2-3 years. Ampol DC tron+ (sold in garden centres as PESTOIL) is by far the best and softest on beneficial insects and the operator as a regular maintenance for general insect pest control. Check out the label for more details.

Cumquats or Kumquats (either name is OK)

Marumi are much less vigorous than Nagami growing on the same rootstock. Nagami has a sharp sweet flavour and Marumi has a soft sweet flavour – there are oil cells in the outer skin of Nagami, but not on Marumi.

Meiwa – I was part of a working party in California in the 80’s to try and resolve the debate about the similarity of Meiwa and Marumi. Both were in the UCR station at Lindcove Field Station in northern California. It is a famous citrus repository from a worldwide point of view and this is documented and authenticated. A comprehensive range of experts in this field made a detailed assessment. It was decided, for all intents and purposes, Meiwa and Marumi were identical, so we adopted the name Marumi.  Any reading you see that quotes Meiwa is pre the1980’s. We have gone to the one name to save confusion. I have not seen any difference and I’ve worked in Thailand, South Africa, Malaysia and Indonesia where I’ve studied the cultivar as well. I’m quite convinced there is no difference.

Sunburn control

Sheryl:   When do you suggest painting the trunk?

Ian:    Use white (reflects the heat) water-based paint EARLY and apply it on all citrus. With Mangoes, don’t dilute. It will last around 5 years. Many trees show sunburn, characteristically a bronze colour on the western side of the trunk followed by excessive dead bark. Check the eastern (protected) side to observe the difference.

Israel

Ian:    Yes, I’ve been to Israel many times. I did learn a lot, as do most when travelling. eg In an irrigation experiment on 10 year old Plum trees, they got sheet piling (from the wharves) and divided the root systems on several acres for a random trial. They put the sheet piling down on each side of the trees – some of the roots were half roots, some quarter some three-quarter and some untouched. A drip irrigation system was fitted to the relevant sections of the new root systems.  The results were startling for the time, but there was no loss of production on the restricted root systems and that meant adequate water could be applied using drippers on a very small area and the tree would develop a root system to cope with those changes. We now know that drippers are effective water savers in applying water by avoiding evaporation losses and because of accuracy of application. If crop potential is pushed to the ultimate limit then there is no water saving there. We should adopt the Israeli term of “tonnes (of crop) per cubic metre of water” to better relate our overall use of our most precious resource. As far as growing in pots though, the Israeli’s grow a lot using nutrient film techniques – you put the plant in the tube – like hydroponics – but the proper term is nutrient film technique (NFT.) They do a lot of this as they are short of water and they developed some superb nutrients for specific use with NFT. ie. Liquid NPK in the 1960’s cost an arm and a leg – you could apply Urea but you couldn’t inject phosphorus or potassium. They developed chemical combinations for drippers that became soluble fertilisers for the industry worldwide.  Now they are in common usage and cost effective.

Publications

Sheryl:   Have you written many papers that we could access?

Ian:        I’ve written more than 60 papers about Horticulture. I’m currently trying to condense these onto a CD and in a book format. It will probably take around two years to complete as I need to revise and update every paper. I’ve written on rootstocks, the role of fertilisers and chemicals, how trees grow to name a few.  

Marcotting

Sheryl:    What plants wouldn’t you marcot?

Ian:       You have to decide first if they are going to go into a pot (OK) or in the ground. e.g. If you marcot Camellias there could be one in the Phytophthora range – pithium, rhizoctonia,  sclerotinia, ready to attack the sensitive bottom of the cutting. eg. In germinating citrus seeds, I am not interested in citrophthora or parasitica at that moment, I’m interested in pithium. The one that kills the Jarrah in WA is phytophthora cinnamomi, and Citrus are immune but there is a huge range of pathogenic fungi, I think I saw 600 species on one list.

Sheryl:   So you’re saying that the majority of marcots in a sub-tropical climate are only suitable for pots?    

Ian:       Yes, for citrus in SE Qld (sub-tropical) you have problems with Phytophthora parasitica right into the tropics. From Sydney down we don’t have parasitica as it’s too cold. Parasitica works year round in warm climates. If you get a cold snap, it will go dormant but it doesn’t happen very often. In the case of Citrophthora it will stay dormant in summer and then activate when soils cool down.

Avocado   

Ian:    We grow Bacon (early) Hass (mid-season) & Reed (late-season) in Renmark and can achieve eight months of harvesting.

pH & climate

Sheryl:    What’s your pH here – everything looks so healthy.

Ian:         pH8.5 – all of the upper areas of SA are alkaline almost without exception. I recently visited a nursery on the Blanchetown Plains (on Goyder’s Line halfway to Adelaide from here) that had a pH11 – we are in a hot, dry desert environment. Last year we got 125mm of rain, previous year was 110 and we’re supposed to get 250. We have not achieved our annual average for so long we don’t know what it’s like.

Bay Tree 

Can be used as a hedge plant or an indoor plant as it is easy to shape.

Grapes

There used to be a collection of 6,000 different vine species at the Viticultural Research Station, Nuriootpa in the Barossa Valley. A new director came in and bulldozed most of them so they’re now back to 1500 – he was sacked after 2 years but the damage and loss was done. At Irymple near Mildura Boulevarde Nurseries have installed a $500,000 glasshouse where they propagate grape vines year round using a French method. Kathy Mullins is the Tissue Culture specialist. Peter Smith owner of Sunraysia Nurseries at Buronga, NSW (across the river from Mildura) is the specialist in the commercial side of Vine Improvement

Figs

Produce two crops. The spring crop comes from completed spurs at the end of the previous year’s growth. By pruning a proportion of long shoots back to, say, 10-20cm spurs in winter, new growth from the spur will produce an autumn crop. Smyrna is the main commercial variety in the world.  For it to be productive it needs to be fertilised with a Capri wasp. The Capri wasp is half the size of a tiny black ant that you can hardly see and lives in the Capri fig. Its cycle starts in there until the point where it emerges from a hole in the Capri fig base about a quarter of the size of a pin head. You place a wire basket on the windward side of each Smyrna tree and put one fig with emerging wasps in the basket– they’re very poor flyers. It’s only when the Smyrna fig base opens that the Capri wasp can go in and lay its eggs. So, every day, you pick another fig and put it in the basket over a period of some four weeks. Smyrna figs have one major crop unlike some of the other types – they are green almost translucent so that when you dry them you can almost see through the fig.

Take cuttings and put in sand to callous and place another pot on top to cut out the light. Most figs appreciate a hot dry summer so you may have problems. For a single tree pruned to contain it to a small size, try a plastic cover over summer harvest. The added heat will not be a problem. eg Marsa Matruh (Egypt’s major fig production area on the Libyan border,) regularly gets temperatures in the range of 40-50C in the summer harvest period! They would be great in pots espaliered where climate moderation is practical. Tony Stevens of Rare Fruit Society in Adelaide (ph: 08.8524 2192) is the Fig guru here and has a collection of some 60-90 cultivars. He could recommend a variety to suit.

Secateurs and budding/grafting knives.

We stock Italian Manaresi secateaurs and a range of left and right handed grafting and budding knives. I have used my own personal snips for 20years and they are still in good condition. They are OK for both left and right handed people also. They have two cutting edges, take much less muscle to operate and produce clean unbruised cuts. We use a standard (fine) Diamond hone to sharpen.

Budding Knife

It’s a myth that Grandpa’s old cowhide strop was a good sharpening tool. It bends and also applies extra pressure on the knife edge. I make Strops by request. Cowhide on a rigid board – smooth one side and nap on the other. If you drop your blade you can straighten the blade on the shiny side of the leather. After you’ve budded say 200 or so buds you can strop the blade on the nap side keeping the blade really sharp without the need for major sharpening and consequent wear. I threw out all my oilstones decades ago as they were seldom straight and they take off too much metal, so shortening the tool’s life. My left handed budding knife is 25 years old and still has the original curve at the tip – most people tell me they get 5 years of commercial use out of theirs. (using oilstones!) Never use a budding knife for cutting plastic because plastic is severe on a blade – just buy a cheap Stanley knife and keep breaking off the segments when they become blunt. I use the plastic end of that cutter to control the depth of cut when removing plastic budding ties and this avoids cutting the plant.

Citrus seed production

We have supplied high quality citrus seed to commercial nurserymen for more than thirty years. The seed is graded, heat treated for pathogen elimination, dried and dusted in Thiragranz (TMTD) prior to heat sealing in one litre HD plastic bags. To do the job we built a stainless steel unit that shreds the fruit separating the seed from the skins. A reciprocating stainless steel screen separates the seed from the pulp. The seed and mucilage is treated with hydrated lime and washed clean. We don’t dry the seed off completely – it’s a bit like giving birth – every ‘variety’ is so different. With Cleopatra mandarin (small seed) you could easily over dry it and then next year the time could be different! This year could be humid – I dry through a controlled Harvest Maid but the humidity I cannot control, so then I could have a problem.  This process still requires a professional touch. The label will give date of extraction, what tree the seeds came from, date, variety, what we treated it with, complete with perishable storage and planting instructions.

Ian propagates trees for the Rare Fruit Society of SA and has some 100 varieties of citrus trees for sale as well as propagation tools so if you want the rare, then write to him at PO Box 2 Renmark SA 5341 or fax: 08.8595 1780    email:   ist@riverland.net.au.

Article compiled by Sheryl Backhouse

Print this entry

Calcium is increasingly recognised as a key to mango production in the Northern Territory for both yield and quality. Observation on yields indicates some of the low yields and fruit drop problems may be the result of low calcium levels and we are becoming more convinced that calcium is essential for good quality, particularly good skin colour. The evidence at the moment is only by observation. Recent research from Africa indicates that mangoes use a lot of calcium – 10 times that of phosphorus and magnesium.

Leading growers in North Queensland have long recognised the importance of calcium. Research by DPIF in the Northern Territory has indicated that growers’ opinion that calcium is important is possibly correct. Most Northern Territory soils including Katherine are very low in calcium – around one quarter of recommended levels. Soil levels should be at least 1000 ppm; most Northern Territory soils are only 250-300ppm.

Not only is the amount of calcium important but the ratio of calcium to magnesium. This should be at least 5:1 calcium to magnesium (expressed as meq/100g) The quality reports have shown the best coloured fruit come from orchards high in calcium, low in magnesium. Unfortunately many Top End soils including Katherine have ratios less than 2:1 (expressed as meq/100g).

Magnesium is present in many Northern Territory water supplies and for mangoes this is a problem. It makes fruit green and soft. The amount of calcium and magnesium in water supplies is variable so soil testing is crucial to get levels right. Test your soils to ensure you have at least 1000ppm calcium and your calcium:magnesium ratio is at least 5:1. NTHA provide a free interpretation service to members.

Calcium can be applied as lime, gypsum or dolomite. Dolomite generally is not recommended for mangoes as it is high in magnesium. Lime is used to increase pH and gypsum is used to increase calcium where pH is OK or high. Foliar sprays of calcium around flowering and fruit set have also been used to improve yield and quality. Current indications are that calcium should be applied at flowering (soil and foliar), after harvest (optional), and especially at the end of the wet season after the heavy rains to set the tree up for good calcium levels before flowering.

The amounts of lime or gypsum required on most Top End soils are large. The recommendations to date have generally been too low. They fail to take into account wet season leaching and the negative effects of high magnesium in most irrigation water. Mangoes appear to use a lot of calcium. Most growers have taken 2-3 years to get their calcium levels and their calcium:magnesium ratio right. Applications of 20kg/tree, three times a year for 2-3 years are not uncommon so get your soil tested. Leaf analysis can be used as a guide but can be misleading as calcium increases naturally as leaves age. It is important to realise that other elements also have to be corrected to get the maximum benefit.

Boron is essential for the best calcium response and should be applied at up to 50gms per mature tree. It is also important to have phosphorus, zinc and potassium levels right. The bottom line is get your soil tested. The best time to test soil (in Northern Territory) is December to February before the main time for application in March.

Note from Sheryl: Refer previous newsletters on talks by Peter Young and Robert Pulverenti

Robert says to only put on 5g per m2 per canopy and water in very well.

Print this entry

My candle nut tree Aleurites moluccanais having a very good crop this year and a fellow told me to pick up this season’s nuts, dehusk and clean, then store in an onion bag tied up somewhere in good ventilation. When next season’s nuts start to fall, the previous ones are ready. I found this way they are easier to get whole and cling to the shell less. I doubt it lessens the effect on my stomach of eating more than 5 or 6 to go through quickly but they taste much better and the few people I have tried them on quite liked them. The nut is the official state tree of Hawaii but here the timber had many uses including canoe construction. A gum extracted from the plant was used to strengthen the tapa cloth they made. The timber is known as Indian Walnut.
Ref:  Stirling Macoboy’s book “Trees for Warm and Temperate Climates”

Authored by: 

Sourced from: 

Sub-Tropical Fruit Club of Qld. Inc Newsletter June – July 2007

Print this entry

This is the title of a tiny book which was first published in England in 1885 and was still in print in facsimile in 1992.  Sheryl has loaned me this 30¢ book sale bargain and asked for some comments. The author, Vincent Holt, presented a case for being much more adventurous in our use of animal-derived foods and offered many precedents for adding “clean-feeding” insects, such as caterpillars, to our diet. He regarded the scavenging-type feeding habits of some of our more normal sources of food  such as lobster, eel and pork, as being much less savoury than those of plant-feeding insects.  He did, however, caution against using insects that feed on poisonous plants.  There is also the consideration that some insects may contain or carry pathogenic organisms which may be harmful or allergenic to humans, or insecticide residues, depending on the circumstances of collection.

Insects that Holt listed as being part of normal diets in non-British societies included locusts/grasshoppers, palm weevils, meal worms, crickets, chafer beetles, toasted moths, the chrysalides of Chinese silkworms, and the larvae of longicorn beetles.  He also mentioned the former use in British folk-medicine of such insects as ladybirds (for colic and measles) woodlice (aperient) and cockchafers (for the plague).  Other insects that had been used elsewhere as food included scale insects, dragonflies, termites, cicadas and caterpillars of butterflies.

A more up-to-date and fact-filled review of some nutritional and economic aspects of “Insects as Human Food” by Gene de Foliart was published in Crop Protection (1992), Vol.11 pp.395-399, and can be downloaded from the internet at:

http://www.food-insects.com/Insects%20as%20Human%20Food.htm

Some general points about choosing insects as foods:

• There are somewhere between a million and ten million species of insect in the world, with a high but unknown proportion of them still to be recognised, described and named.  Perhaps 1500 species have been recognised as edible and these are mostly used in tropical countries where insect diversity is very high and the availability of nutritious foods is sometimes limited.
• It is useful to check which insects were used as food (but not medicine) by local aboriginal people and how they prepared them, eg. bogong moths and their larvae. An informative article on this subject by Cherry can be found at http://www.insects.org/ced1/aust_abor.html
• Cooking is recommended for most insects being used in modern cuisine as novel foods or garnishes, e.g. fried grasshoppers and fried bee pupae. 

Many common foods, such as flours, cereals, fresh and frozen vegetables, and fresh and dried fruits, can contain a few small insects or larvae (dead or alive) insect parts and/or droppings, which we normally consume without noticing. Fruit fly larvae, perhaps?The nutritive and caloric value of some edible insects can be similar to that of plant or animal-derived foods, but of course varies depending on the species and the part consumed – e.g. whether the chitinous exterior is removed. Insects such as termites and caterpillars, locusts and ants which have been eaten in quantity in some traditional cultures can provide extra nutrients such as proteins and fats to what is sometimes a rather limited range of foods.

Print this entry

This is a method of inoculating your plants with beneficial fungi. You can make your own from your own local soil. The soil that you make will be rich in beneficial fungi. This will be the ‘inoculum’. It takes about an hour or less to set up and is very simple to maintain.

What are mycorrhiza?

Mycorrhizal fungi are a group of soil fungi that infect the roots of most plants. The fungi is not a pest or parasite as it supplies the plant with nutrients like phosphorus, copper and zinc, as well as increasing water availability. The plant supports the fungus with carbon in the form of sugars. This symbiotic relationship does not affect the plants, as they produce excess carbon. In fact, lack of water and nutrients is more often the limiting factor to plants’ growth and establishment. Mycorrhizal fungi are found in most environments, although their importance is greater in more extreme environments, where nutrients and water may be limited. There are very few plants that do not form mycorrhizal associations at all, although most can grow without it. In plants that have been infected by mycorrhizal fungi, the fungus is actually the chief method of nutrient uptake, not the roots.

There are several types of mycorrhiza, the type that we are interested in are by far the most common and are called arbuscular mycorrhiza (AM). This type of mycorrhiza is invisible to the naked eye but forms a fine mesh through the soil. They enter the cells of the roots where they form branched arbuscles within these cells, this is where the exchange of nutrients and carbon occurs.

How do you know if a plant species can be a host to this type of fungus?
The vast majority of plants do form AM. This includes the majority of domestic and wild plants. However some species do not form this association, these include pines, firs, spruce and oaks. It would be impossible to list all the species and their mycorrhizal associations, so if you are in any doubt then contact us and we can confirm if this species will benefit from the inoculation method.

Results that you can expect
The most notable improvement should be an increase in survival rate. It has been shown that mycorrhizal plants cope better with stresses such as dry conditions and disease than non-mycorrhizal plants. Depending on your conditions and the species that you are using you may also notice an increase in growth. This is due to the plant accessing more phosphorus from the soil (this varies from just a few percent to double the normal growth). There are other benefits that mycorrhiza can bring to the soil. Its fine structure helps stabilise the soil structure, slowing both sheet and subsurface erosion. Under the soil, invisible from above, a network of fungal hyphae will start to spread from your plant, gradually colonizing other plants and in effect starting to rebuild a healthy ecosystem. The underground structure is the key part of restoring the ecosystem. The plants then act as fertility islands, with increased organic matter, better soil nutrient levels and with increased nutrient cycling.

Collecting your “Starter Soil”

Materials needed: spade, sacks and/or wheelbarrow to move soil.

Where? Around 80% of vegetation forms mycorrhizal associations. The infected plant roots and the spores and hyphae of the beneficial fungi are in the soil and can colonize new plants. You can be pretty sure of getting a good starter soil from any undisturbed area containing native vegetation including most grown trees, woody shrubs and perennial grasses. The best place to collect your starter soil is from under local native vegetation that is growing well in an area that has not recently been cultivated. It is good if you can collect some of the soil from under the same species as that on which you plan to use the mycorrhizal inoculum

 (i.e. your tree, shrub or crop species).

Method: Clear away about 0.5m2 of the vegetation underneath your target plant. Dig down to a depth of about 25cm collecting the soil and as many fine roots as possible. It is better, but not essential, to collect from under several different trees and shrubs. With stony soil it is best to sieve it to get rid of large stones.

2. Multiplying the mycorrhiza

To multiply the mycorrhiza from your starter soil we use a ‘trap-pot or ‘trap-trough’’. This method grows mycorrhizal dependent annuals in the collected soil. These plants, often called “bait plants”, will become infected with the mycorrhizal fungus causing the fungal population to multiply. Often two bait plant species are grown together to enhance different mycorrhizal fungal species multiplication. One of these will be a species of graminacae or allium, and the second will be a species of legume. Examples of these species are shown in the table below. Combining maize and beans, for example, is a good choice as they grow well together. It depends, however, on what you know to grow well in your area and on what you have available.

Select Species 1	Select Species 2
Graminacae	Allium species	Leguminacae species
Maize	Leeks	Alfalfa
Millet	Onions	Beans
Sorghum	–	Clover
Wheat	–	Peas
Oats	–	Lentils

Materials needed:

spade, plastic sacks/pots (5 litres or larger), seeds of your two selected species, water.

Where?

The best place is in a site that will not be needed for at least three months and where you can keep an eye on it. It will need regular watering, adequate light and protection from herbivores.

Method:

Take your starter soil to the site you have chosen and then either fill one or several plastic pots/basins (depending on how much inoculum you need). Alternatively, a trench can be dug into the ground and lined with the plastic sacks or other material available. This is what we call a ‘trap-trough’. The pit should be dug about 100cm x 50cm to a depth of 50cm and then lined with the plastic sacks. Plastic sheeting, bin liners or sugar sacks will be fine. Perforate the plastic to allow for drainage. Make sure that it covers the whole basin with an overlap. Place stones on the overlap and fill the trough with the soil. Soak the seeds of your two chosen species overnight. Plant them closer than normal, alternating the species.

Note: the soil that you dig out of the trench can be used to fill in the holes where you extracted soil from under the local vegetation.

How much inoculum do you want to make?

This depends on what size container you will be planting in, but estimate about 1/6 of each pot to be filled with the inoculum. If using on crops see ‘inoculating crops’ below.

3. Maintaining your trap-pots or trough
Once you have set up your trap-pot or trough you can more or less forget about it. Just keep it regularly watered. In this time the roots of the bait plants will be developing and forming the association with the mycorrhiza. Depending on the season you might need to shade it or protect it from frost. If growing trap-pots then they can be moved into a more sheltered area.

4. Three months later…

Ten days before you are ready to use the inoculum, the bait plants should be cut at the base of their stem and watering should be stopped. This kills the plant, and tricks the fungus into producing reproductive spores. Then, after the ten days, the inoculum is prepared by pulling up the roots of the bait plants which should be chopped into roughly 1cm pieces and then mixed back into the soil from the trap-pot or trough. This mixture of roots and soil is the inoculum.

5. Using the inoculum

The inoculum can be used on a wide range of different trees, shrubs, crops and garden plants. In all cases the plants should be given the same care as normal. A small amount of compost will complement the addition of mycorrhiza but no artificial fertilizers or herbicides should be added.

Inoculating trees, growing them from seed:

Materials needed: inoculum, seeds, growing tubes or plant pots, soil, compost.

Method:  Two thirds of the pot or growing tube should be filled with normal soil, with a little compost mixed in, if available. Then add a layer of inoculum and finally another layer of normal soil into which the seed is sown. The inoculum layer need only be a couple of centimetres deep. This means that when the roots grow down the tube they will come into contact with the fungus, and quickly become infected. The trees are then cared for as usual, and planted out at the same time as normal, to coincide with the growing season. The trees that have been infected with the fungus should be much better equipped to cope with shortages in rainfall, and will also improve the mycorrhizal potential of the surrounding soil.

Inoculating pre-grown trees:

Materials needed: inoculum, trees, spade.

Method: dig the hole where you will plant your tree and throw in a spade-full of the inoculum. Place the sapling in the hole and sprinkle a little more of the inoculum around the edges as you fill it in. If you are adding compost then dig the hole slightly deeper, add the compost, cover over with normal soil and then add the spade-full of inoculum.

Inoculating crops:
Method: Put a pinch of inoculum into any hole that you are about to plant into. Or mix a couple of handfuls of the inoculum with seeds that you are about to sow and plant as usual. If transplanting then soak the root ball in water and then dip in the inoculum. The root ball will then have a coating of inoculum. Plant as normal.

When you have used as much of the inoculum as you need, the trap-pot or trough can be topped up again with more starter soil, re-planted with bait plants and the cycle repeated. This ensures that there is a ready supply of inoculum all through the year.

The trap-pot or trough needs to be set up three months in advance of your scheduled planting in order for the mycorrhizal population to fully mature.

A word of caution:  It is possible that you might accidentally cultivate pathogens rather than beneficial organisms. Be observant and choose soil carefully!!

Print this entry

I’d like to welcome you all to my place today and probably the best idea would be for you to ask me questions.

Banana:   I grow the Ducasse and another variety but have trouble with the banana beetle borer. 

David Holdom:  As far as I know, chemical control is difficult and there is no effective biological control either.  I understand that control is via management of the plants by replacing them regularly and destroying infected material was the most practical way. 

John Ambrose: My understanding of it is that there are some chemicals that can be used but you just have to live with it but you can’t wipe them out with any pesticide I was told. 

Nguon: The DPI recommended a chemical which would last for 2 years but it didn’t work.

Cambodian Mango I have one which tastes very creamy but I’ve never had a crop as it flowers very early (there were flowers on several of his trees) If I ever get a crop on, they always drop. The trees are 6 years old.

George: A lot of mangoes flower too early down here in SE Qld especially if its been wet and if you’ve been adding nitrogen (the chook yard was housed under the mangoes) so don’t water in the winter and don’t fertilise and in the spring when they start to flower in the cold period, just break the flower off and 6 weeks later it will reflower. With early flowers when they set, what happens is if it is a cold night, the little embryo in the seed dies and the fruit gets to a certain size and drops off. You could also prune them and keep them small and do this straight after they finish fruiting in summer. It’s a classic problem for us: we’re just not quite in the right climate zone. Bowen is perfect: dry/coolish winters but we can get a bit of rain in the winter.

Custard Apples – Bob Cosgrove: When I was a kid the best place to grow this fruit was in the chook yard! I’ve seen a Pinks Mammoth that weighed 13lb.!!!

Guava   This is the main crop on my property and I sell it to Sydney. I grow the white fleshed one which I bought as a fruit and propagated the seeds because it was a really nice fruit.

Sheryl: How much do you get for them? 

Nguon:  Between $3.00 – $4.50 kg.  I bag all the fruit so it makes the fruit look nicer and it also helps against fruit fly but not 100%. I still have to spray. Sheryl When does the crop ripen?  Nguon  All year round but the main crop is winter. I have to thin. Fertilise with Q5 to start in spring – about 3 handfuls per mature tree then I put on CK88 or CK66 when the fruit is about an inch. They like plenty of water and fertiliser.

Jackfruit   I sell my Jackfruit for $4.00 kilo. Mine fruit all year round. I pick them when they get a little soft to feel and it has a very strong smell. Fruit bats don’t touch them. All my trees are seedlings from the one fruit and they’re not all the same. I have both soft and hard and one that is crunchy. Cut back any inward growing branches and just leave 1 fruit per stem.

Jujube   I have about 6 trees and all have thorns. Mine flower and fruit all year round but the heavy crop comes in June (winter). If I don’t spray for fruit fly, I don’t get a crop. We spray the whole tree with Lebayacid but it’s 2 weeks before we can pick although winter is free of the pest. Rogor only has a 2 day withholding period.

Longans  I have the Thailand variety but the bats get the whole lot although we got a good crop last year because I netted.

Neem    In Darwin they’ve been using it as a boundary hedge to stop termites.

Michael: The neem is used overseas as an insecticide but there is always something that will eat it. In India there is a beetle which feeds voraciously on it and they seem to survive very well! It is not registered for use here as an insecticide.

Karin: In Kenya they make a powder out of it and it’s the cure for 40 diseases!

Nguon: I also grow Persimmons/Soursops/a couple of different types of edible Bamboo (one is large and you boil the shoot then throw the water away and the other is a thin small leaf Taiwanese type which is sweeter than the other and you can keep the water with this one/and I have a  leaf of a Bamboo that you can use to put around sticky rice or flavouring cake/and the root of the Prolah (Cambodian word) which is crushed and mixed with white wine and used as a medicine.

Sheryl: I asked a friend who spends time in Cambodia every year and she looked up her Cambodian dictionary and “prolah preah” which is Helicteres elliptica. It  is a shrub that grows to around one or one and a half metres in clear forests and the roots are used in a remedy for fractures.

Article compiled by Sheryl Backhouse

Print this entry

Texas A & M University  http://aggie-horticulture.tamu.edu/propagation/propagation.html   A great propagation web-site which includes all the different types of grafting.  There are “animated gifs” ie clicking on a diagram sets it alive so the transfer of budwood to scion is shown in action. If you want to have all this available at any time, you can save the main file and all the illustrations in a folder on your hard drive and view it at any time by opening the main file with your web browser.                                                                                                                                                                         

Essentials   Essentially the treatment (also called marcotting)  is to girdle a shoot and surround the wound with moist material until roots emerge, when the rooted shoot is severed from the parent and established as a new individual. This is an ancient method well described by many writers as a reliable though somewhat tedious way of propagating very many woody plants, including avocado cashew and mango.

Age of Shoots   Judging by the many results of trials with a wide range of species it would seem that young shoots, with a fast growing potential in a position on the parent tree where there is adequate light, respond best to marcotting. Firm shoots sufficiently lignified to withstand the necessary manipulation, yet young enough to respond to treatment, should be selected. Generally it will be found that one year old shoots with a good supply of leaves and leaf-buds are ideal for rapid root initiation and development, which largely depend on the downward flow of essential substances from developing leaves and shoots growing above the marcot. Thus it is that the phasic development of the actual shoot and not that of the parent tree as a whole is vital. The shoots should always be young, and can be obtained on old trees by heading them back. In mango, shoots of less than two years of age have been shown to give a higher percentage of rooting than older ones. However, with cashew it was found that one—year-old wood was better than current season’s growth.

Girdling and wounding    It has sometimes been suggested that slicing, notching or half-cutting through are alternatives to complete girdling or cincturing, but these partial interruptions of the downward movement of materials are less effective than complete girdling. Where success has followed mere wounding it may have been brought about by extensive tissue damage, and consequently girdling effect, or by excessive use of a highly concentrated growth substance.

As to the best season for the operation, work in various countries has shown that there is no major advantage in choosing a particular month. The condition of the shoot is the important factor; it should be young and active but not too soft, and one or two year old shoots have generally proved the most suitable. A practical consideration of some importance is to time the operation so that the rooted shoot is due for removal for transplanting early in the rainy season so as to facilitate establishment.

The position of the cincture, whether above or below a bud or midway along an internode, is relatively unimportant but it should be placed where it can be conveniently wrapped and be supported either by being tied to a neighbouring branch or to a stick or cane. Another practical consideration is the eventual size of the rooted layer. The rooting of very large branches leads to establishment difficulties. Size reduction by pruning, at the moment of transference, may aid survival but may result in a misshapen plant based on lateral development. Suitable shoot sizes about the cinctured position have varied from 9 to 24 inches (23 to 61 cm) in length and from pencil thickness up to half an inch (1.25 cm) in diameter. A cincture a little above the base of the shoot will be ideally placed with regard to root formation and support.

The cincture itself is made by removing a complete ring of bark. Widths advocated have varied from one-eighth to three inches (0.3 to 7.6 cm). The essential aim is to stop the downward movement of carbohydrates and growth substances so that they accumulate above the cincture and are available for the initiation and development of roots.

This interruption of flow should be as complete as possible without interfering with the upward passage of water and other materials to the shoot above. An eighth—inch (0.3 cm) girdle will heal and form a bridge too quickly, whilst a three-inch (7.6 cm) gap is excessive. An inch (2.5 cm) —wide girdling will generally serve and this can be made by two encircling cuts and the removal of the intermediate rind. The operation can be done with a sharp knife or with a double bladed tool. These cuts should not enter the wood (xylem) of the shoot for this not only checks the upward sap flow but, by weakening the shoot structure, increases the risk of loss by breakage. The vital necessity of preventing the downward flow of materials cannot be overstressed. Some workers have treated the bared wood— surface with disinfectants or other chemicals in an attempt to prevent the formation of a new rind, but with no clear benefit. A somewhat more efficacious treatment is to rub a pad of steel wool, or other abrasive, around the cincture to remove all traces of meristematic tissue. Another method is to pull twine or strong plastic thread very firmly into the wound to prevent bridging by callus:

Synthetic growth substances    It has become customary to apply synthetic growth substances to the upper part of the cincture and to about the first inch (2.5 cm) of the bark immediately above it. This is not essential for readily rooting subjects but has generally proved helpful in speeding root formation and in increasing the number and length of roots. Many substances have been used with success, the most popular being indole acetic acid, indole butyric acid and naphthalene acetic acid, or mixtures thereof. They may be applied diluted in alcohol, in inert dusts or in grease bases s as lanolin.

From a survey of the literature it would seem that the most effective single substance for assisting root formation is indole butyric acid (IBA). To prepare an alcoholic solution of IBA (or other crystalline growth substance) dissolve 1 g in 50 ml of ethyl alcohol, methyl alcohol or methylated spirit and then dilute this with an equal volume of water to make 100 ml of solution containing 10,000 p.p.m. IBA. To dilute the 10,000 p.p.m. to 5,000 p.p.m. add a further 100 ml of 50/50 alcohol/water mixture. Stored in well—stoppered opaque bottles in a refrigerator, the solutions retain their activity indefinitely, and should be strong enough for shy—rooting subjects.

Dusts containing synthetic growth substances ready for use may be purchased or can be made as follows. To make a dust containing 10,000 p.p.m. of growth substance dissolve 1 g of the substance in 40 ml of methylated spirit or 95 per cent alcohol, and stir this into 100 g of pharmaceutical talc to form a smooth paste. This should be done in a darkened room away from strong light (117). Stir the paste while it is drying until it becomes a fine dry powder. This prepared dust remains active for six months or more if stored in a closed opaque container in a refrigerator.

Lanolin pastes, which are particularly convenient for use in marcotting but are now regarded as an obsolete treatment for cuttings (5), are made by stirring the growth substance into the molten lanolin and then allowing it to cool (93). To make a paste containing 5,000 p.p.m. of growth substance melt 200 g of lanolin and thoroughly stir into this molten lanolin 1 g of IBA, or other growth substance required. This prepared paste will keep indefinitely if stored in a well-stoppered opaque glass vessel within a refrigerator.

The alcoholic solution is conveniently applied by means of an artist’s camel—hair brush, the liquid being contained in a small glass bottle held close to the cinctured shoot. The bottle should be stoppered between each individual application. The liquid should wet the lower inch (2.5 cm) or so of the bark close above the cincture as well as the adjacent cut edge. An inadvertent wetting of the exposed wood (xylem) is of little consequence. The solution should be allowed to dry before applying the medium. Dusts can be generously applied by means of a half-inch (1 cm) brush.  If insufficient dust adheres, the bark above the cincture should first be wetted with water or a mixture of 50/50 methylated spirit and water.Lanolin pastes are applied by means of a small pliable serrated spatula, a brush of stiff bristle or by the finger protected by a rubber finger-stall.                                                                                     

Rooting media    The choice of the rooting medium to place around the cincture has been widely studied and the present view is that a wide range of media are satisfactory (see page 15 A good medium should be open in structure to permit air and moisture movement and be able to retain its structure throughout the rooting process. It should therefore not ferment or otherwise breakdown, hence live sphagnum moss has been widely accepted as a basis, but coir fibre and coir dust, wood shaving and sawdust have all proved excellent as basic ingredients.

Work with cashew in Tanzania (89) showed that vermiculite alone was superior to fibre, moss, coir, sawdust or a 50/50 mixture of vermiculite and sand. It is an advantage if the selected material is light in weight and holds together whilst being placed in position during the wrapping procedure. Whilst an open, light—weight medium provides an excellent rooting environment, it should be remembered that the main hazard in marcot propagation occurs during transference and establishment. From general experience it has been learned that transference to soil or mixtures thereof, whether in containers or the open nursery, is more readily accomplished if the marcotting medium contains a modicum of loan or clay soil. A medium of equal parts clay soil and sieved leaf mould has proved superior to moss alone in regard to rooting and survival of mango air layers in India (120) but it should be remembered that heavy additions of soil increase the need for extra support for the marcot.

Wrapping the air layer   The medium should be well moistened. Fibrous material should be thoroughly wetted and squeezed free from excess water at the moment of application. It may be convenient to pack the material round the cinctured part before placing the wrapping over it. Often a better way is to place the medium on the wrapping and so lift it into position. Polyethylene sheet is an ideal wrapping material, being both water-tight and transparent, obviating the need to water the marcot and enabling the new roots to be seen when they come through the rooting medium. As with many other kinds of enveloping material polyethylene may be punctured and torn by birds. Where this occurs the only remedy appears to be an outer cover of really tough, resilient material such as a piece of inner tube from a car tyre. The polyethylene film must be thin enough to be wrapped and folded round the shoot to form an air—tight enclosure. Thicknesses of from 100 to 400 gauge (0.001 to 0.004 in or 0.025 to 0.1 mm) are suitable Thicker films are difficult to fold sufficiently tightly to prevent drying of the enclosed medium. Occasionally it is possible to maneuver a length of polyethylene lay—flat tube, three or four inches (8 or 10 cm) wide, over the top of a shoot bearing only small leaves and to fix this below the cincture and then to fill it with rooting medium before closing it tightly above. Mostly a Square of sheeting must be used, the size varying with the situation. Pieces measuring about 7 x 10 inches (18 x 25 cm) are normally large enough to contain a ball of medium some three inches (8 cm) long and 2½ inches (6.5 cm) in diameter, leaving two inches (5 cm) for a double-fold lengthwise and two inches (5 cm) at either end for closely wrapping round the shoot.

Having made the cincture and applied the growth substance, a handful or so of moist medium is placed in the middle of the wrapping and immediately lifted into position round the shoot, the two edges of the wrapping are matched together and folded over twice to hold the medium quite firmly. The lower open end is closed by a twisting motion very firmly round the shoot and there tied or taped with plastic strip or strong adhesive tape. The medium is firmed below the open top, using the fingers, before tightly taping. The wrapping and tying must be done in such a way that no opening is left for evaporation from the medium. The tie at the top end should always begin on the bare shoot and be spiralled down on to the wrapping to prevent excessive rain seeping down into the marcot. Sometimes, in spite of all wrapping precautions, marcots become waterlogged. This appears to be due to overheating of plastic wrapped marcots by direct sunshine followed by heavy rain which, flowing down the shoot, rapidly cools the marcot, setting up a strong suction press which draws water into the marcot through even the smallest opening. An outer loose covering such as that SUgge5 as a protection against birds, or a white paper Covering, Will reduce excessive water intake. In the absence of plastic materials or rubber sheeting a great variety of wrapping materials have been used such as hessian cloth, various fibres, barks or leaves, or even old boots, but the distinct advantage in efficiency of using transparent, foldable plastic sheet, not least the absence of the need to water a plastic-covered marcot, ensures its present and future popularity.                                                                                                                           

Transference of the rooted air layer   When the marcot has rooted sufficiently to ensure successful transplantation (the period may vary from as little as 30 to more than 100 days) the procedure of separation should begin. Ideally this is done in stages, the branch is half nicked close below the wrapping and completely severed one or two weeks later. At this moment of separation the rooted marcot is vulnerable to adverse weather conditions and it is advisable to place it in a container and to take it through the full nursery procedure as described for young seedlings or newly rooted cuttings, including adequate nutritional treatment to build a fully self-contained plant for transference to the plantation.

Ref: Oscar – Hawaii   Choice of wrapping for air layers depends on climate and personal preference. In the tropics I find that transparent wrap is not so good because if the sun hits it can bake the roots. I like to use two layers of aluminium foil, very easy to apply and no ties necessary. The reason I use two layers of foil is I found if I use only one layer sometimes the birds will peck a hole, but no problem with two. I don’t use any tape or any other tie. Just counter twist the foil on top and bottom. Some birds are definitely more bothersome than others. We don’t have crows here, which I remember do seem to get into everything. Only 3 main types of birds here: mynah, cardinals, and japanese white eye. Another option if you can’t get foil is to use one layer transparent plastic and another layer opaque, or if you can get very thick poly just use one layer opaque. Sapodilla can be grafted when about 30cms or more, but is easiest to graft when they are almost pencil thickness. Chikoo is the Indian name for chico (probably a transliteration), or sapodilla. It is possible to air layer them, but they take a very long time, up to one year, and have low rate of success.     

Ref: Joe Real   Citrus info from the Philippines   Marcotted trees tend to remain dwarf but weakly anchored, but it depends on the type of cultivar. For example, the marcotted rough lemons and lisbon lemons could develop extensive root system as strong as grafted trees. This I know because I marcotted and grafted them and they performed the same, but not true with mandarins and oranges, the marcotted ones are poorly anchored. With Calamansi, the marcotted ones are not as good as the grafted ones, but they remain smaller. If smaller trees are good for you in wind-sheltered areas, marcotted trees could suit your needs. If you want bigger trees that are well   anchored, marcotted trees are not generally for you. One big advantage of marcotted citrus trees is that they bear quality fruits much earlier than grafted ones. Those citruses grafted unto seedling rootstocks would develop quality fruits 3 to 7 years after planting. They could produce fruits right away, but the quality won’t   be as good until the tree reaches proper size. The marcotted trees will have good quality fruits right away. This is because with grafted trees, some of the juvenility in the rootstock is passed on to the grafted cultivar. If the rootstock is very old, like a mature tree, then you get quality fruits right away, but if the rootstock is a young seedling, expect 3 years at the fastest for a nice quality fruits.   

Print this entry

Nematodes are microscopic animals found in the soil, within plant tissue and within water.  Some nematodes are damaging to plants, but there are also beneficial nematodes found within organic matter that parasitise destructive nematodes. Nematodes that attack plant roots are the most common. They cause root galls and excessive root branching.  This affects the plant’s ability to take in water and nutrients, wilting and stunted growth. Sandy soils are particularly prone to nematode infestation. Control can be achieved by incorporating organic material into the soil, growing nematode resistant varieties, crop rotation and paying attention to hygiene procedures. For severe infestations you can treat vegetable growing areas with a mix of molasses (2 tablespoons per litre of water). This should only be used on areas that will grow nematode susceptible crops (tomatoes, potatoes and capsicum). Do not use across the entire vegetable garden as this mix has the potential to kill worms.

Sooty Mould

Scale insects and their associated sooty mould are common pests of many plants including citrus, gardenias, lillypilly hedges and other native plants.  Conventional oil based controls, see [Do It Yourself Controls – Oil Spray] can be used, but should be diluted to half strength on fine leaf natives or plants with hairs on the leaves.  Avoid using oil based products on plants with grey foliage. Commercial oil sprays include Eco-Oil. Soap sprays are also effective, but must be used on a regular basis. Pyrethrum based products can also be used.

Stylar End Rot

This disease affects Tahitian limes and occurs where fruit is left to over ripen on the tree. The base of the fruit develops a soft rot and fruit fall to the ground. The internal flesh also shows deterioration when cut. Fruit should be harvested while still green in colour prevent this occurring.

Sourced from: 

Sub-Tropical Fruit Club of Qld. Inc Newsletter February – March 2007