2020

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Most plants can be propagated from cuttings however, some plants are quite difficult to persuade to grow roots, whilst others may take an inordinate length of time (years) to “strike”. Do not let such problems, either real or imagined, prevent you from trying. Propagating mix: Generally, sand, or vermiculite, or a mix of the two will be satisfactory. Even compost and/or composted wood-chips have been used with success.

Soft-Tip Cuttings: Usually taken in Spring. Very few fruit trees are propagated by this method, but generally anything in the Solanum group, such as Pepinos and Tamarillos will be fine. Take a reasonably substantial length (normally not less than 10cm) from the growing tip of the branch [twig]. Make the cut directly below a growth-bud. Remove all but the very top leaves, and reduce the size of the leaves which are left on, this reduces evaporation-loss of liquid from your cutting. Plant your cuttings in the propagating-mix to ¾ of its length. A rooting-hormone powder may be used, but is generally not necessary. Do not allow the propagating mix to dry out, and mist over the cuttings daily. Some method of supplying bottom-heat would be an advantage, such as sitting the container with the cuttings in the top of a hot-working compost heap. The cuttings may be potted-up as soon as the roots appear, often after only 3 weeks. Problems: Fungal infections resulting from the moist, humid conditions may require treatment with a fungicide.

Semi-Mature (Tip) Cuttings: Usually taken in Autumn. Citrus, Feijoa, and other evergreens can be propagated by this method. Note that many Citrus are prone  to soil-born diseases, and therefore only resistant varieties such as Poncirus trifoliata and citrange should be propagated by cuttings, usually for use as rootstocks. Take a reasonably substantial length (normally not less than 10cm) from the tip of a branch [twig] that has ceased its seasonal growth but is still green and soft. Make the cut directly below a growth-bud, or, if the propagating-wood is short enough, tear it off the main branch, leaving a “heel” of older wood attached. Remove all but the very top leaves, and reduce the size of those leaves, to reduce evaporation. Plant the cutting in the propagating mix to ¾ of its length. Do not allow the propagating mix to dry out. Some method of supplying bottom-heat is frequently an advantage. Commercial growers often heat the benches upon which the cutting trays are placed. The little plants should be rooted and ready to pot-up in Spring. Problems: Fungal infections are the worst danger, but watch out for snails and slugs.

Hardwood (Mature) Cuttings:  Usually taken in late Autumn or Winter. Deciduous fruit-trees can usually be grown by this method, but evergreens are also worth trying. Take a substantial length (normally not less than 15 cms long, or less than ½ cm thick). Make a slanting cut just above the terminal growth-bud, just as if you were pruning. Make a horizontal cut immediately below the bottom growth-bud on the cutting. Now you know which way is up, and you won’t plant the cutting upside-down! Remove any leaves. A slight vertical slit in the bottom of the cutting may increase the callous (rooting) area. Plant the cutting in the potting-mix to at least ¾ of its length (some propagators only leave the top bud above the surface). Rooting-hormone is generally a waste of money for hardwood cuttings. Do not allow the propagating mix to dry out. Some form of bottom-heat may help things along. The plants should be ready to pot-up by the following Winter. Some plants can take a very long time to produce roots: just put them back in and wait for another year!

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Like many of the Mediterranean and Middle Eastern fruits, pomegranates (Punica granatum) grow well in South East Queensland. However, they do not seem to enjoy very great popularity as a fruit.  Perhaps this is because people don’t like the fuss involved in extracting the seeds, or don’t realise what can be done with the fruits, which can be made into jam, wine or the sweet syrup called grenadine. They may have forgotten what a delightful treat it is for small children to sit down with a large, red, juicy pomegranate and carefully extract the sweet, flesh-covered seeds, and then be allowed to spit the seeds out over the veranda rails.

I think it is time for a renaissance of the pomegranate, especially as there are now some superb cultivars available, with very large fruit – and even a seedless variety.  They have many benefits – being hardy, attractive, manageable bushes or small trees that tolerate a wide range of soil conditions, as well as wind, heat, cold and drought. Being ‘self-fruitful’, they can pollinate themselves. They have dense green foliage in all conditions (there are also variegated types), although in our climate, they are semi-deciduous. The distinctive flaming orange/red flowers are produced profusely in spring in our region. They can be grown as a hedge if planted about 2m apart.

I have taken an interest in pomegranates after I was given some cuttings of a cultivar described as having large, sweet fruit. These came from a woman whose family come from Dubrovnik in Croatia, and had brought the original tree to Australia many decades ago.  Pomegranates grow well in that region and around Italy, where they are much more appreciated as a fruit than here in Australia.

I found that the cuttings that I was given (about pencil thickness) struck very easily. The cuttings are best started in winter. All I did was strip most of the leaves, shave the cambium layer of bark from the bottom 40mm or so of the cutting, dip the base in rooting powder, and plant in good potting soil, with plastic bags over the tops of the pots to retain moisture. The cuttings produced new leaves within 2 weeks, and had good root systems in another 3 – 4 weeks.  A year later, I have sturdy trees in the ground that are now up to one metre in height, and growing vigorously. However, we will have to wait up to three more years to see how the fruit turn out, as the usual age for fruiting with pomegranates is 3 – 5 years. 

The pomegranate needs full sun and a long hot summer for good fruiting. However, they can also withstand low temperatures of -9° to -12°C and are very drought-tolerant (Tous and Ferguson 1996). Because they are adapted to dry summers, I think it is good idea to plant them in well-drained areas in our subtropical climate. A site with a slight slope would be ideal. Although there should be adequate rainfall in South East Queensland for fully established pomegranate trees, we have been having some very dry summers lately. In this situation, additional watering to maintain soil moisture in late summer and early autumn will help reduce the chance of the fruit splitting.

Another good thing about pomegranates is that they don’t need much care in the way of pruning. All you really need to do is some minimal pruning, such as removing any suckers at the base of the plant. Fruit is borne on the spurs which arise from 2 – 3 year old wood, so any pruning should retain sufficient of this older wood on the tree. They do have a tendency to produce suckers from the roots. You can also prune pomegranates to a particular desired shape. For a tree-shape, only allow one trunk to develop. If you are concentrating on fruit development rather than ornamental values, it is a good idea to cut the plant off at 50cm when planting out, and then allow three to five shoots that arise from the stem to develop into a framework (NSW Department of Agriculture, 1983). Alternatively, you can allow them to become bushy, or shape them into a hedge. A light annual pruning will encourage good quality fruit. According to Sheets, Du Bois and Williamson, pomegranates are adapted to many soil types from pure sand to heavy clay, but produce fruit the best when grown on deep, heavy, moist loams with a pH in the range of 5.5-7.0.  Fertilise in early spring and early summer. It’s best not to fertilise too close to fruit maturity (they ripen throughout autumn in South East Queensland)

There are now several varieties to choose from. ‘Wonderful’ has a very red fleshed, sweet fruit. It was developed in California and is available in Queensland. ‘Elcite’ is a variety that we have growing, which has produced well since its third year. Another that is readily available locally is ‘Galusha Rosavaya’. All these are currently in stock at Daley’s Nursery (www.daleysfruit.com.au). There is a nursery in Western Australia called ‘Fixed Stars, that specialises only in pomegranates – and will ship cuttings around Australia during June to August. They have at least a dozen different varieties, including a seedless one called ‘Jallore Seedless’(www.fixedstars.com.au).

Don’t be discouraged if your pomegranates drop their fruits in the first year or two. This is common in the first few years. However, it is worth noting that fruit drop is aggravated by over-fertilization or excess irrigation, both of which favour vegetative growth (Sheets, Du Bois and Williamson). When you do get fruit, it is best picked just before the fruit splits. Note that they do continue to sweeten off the tree. If dried out in sun, the shell becomes quite hard, and as long as the fruit has no damage on the skin, they will keep like this for up to 4 months.

Italians call the pomegranate ‘miela granata’ which means ‘grainy apple’. This is because of the multiple small segments contained in the fruit. These ‘grains’, which have red, pink or scarlet flesh surrounding a small seed, is technically called an ‘aril’. Because of the very high juice content (76% to 85% of the arils), it is well worth juicing. However, you do need to separate the arils from the rind before juicing, otherwise the juice will have a high tannin content, and be unpalatable. Interestingly, for commercial production, the whole fruit is juiced, and then the tannins are removed with the addition of gelatine. To make grenadine, add sugar in equal parts by volume to the juice, leave for two days, then bring to the boil, simmer five minutes, and bottle it hot in sterile bottles (Wilson).

Overall the pomegranate is versatile, attractive, tasty, and can adapt easily to the range of conditions in South East Queensland. The fruit is great fun to eat fresh from the tree, and is a good conversation starter for guests – most of whom will remember eating pomegranates in their childhood.

References:     NSW Department of Agriculture, 1983. Pomegranate Growing, AgFacts H3 1.42.

Sheets, M.D., Du Bois M.L., Williamson, J.G., 2004. The Pomegranate, Fact Sheet HS-44, Horticultural Sciences Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida.

Tous, J. and L. Ferguson. 1996. Mediterranean fruits. p. 416-430. In: J. Janick (ed.), Progress in New Crops. ASHS Press, Arlington, VA.

Wilson, P. The Pomegranate: More than a Multitude of Pips, Grassroots 19.

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On a recent visit to the Museum here in Brisbane, I saw an exhibit on the Pituri bush which was used by the Aborigines. It grows to around 2.5mtrs. and is classified as a clonal shrub ie not propagated by seed. 

Our early European explorers in the Simpson Desert noticed the Aborigines chewing the leaves of the Pituri and discovered that it made them forget their thirst and hunger and made them happier. The leaves were moistened with saliva, roasted over a low fire then rolled to form a plug which they would carry behind the ear and used when necessary. The dried leaves were also mixed with ash of a certain Acacia and the mixture was believed to be more potent and as the ash had an alkaline effect, it released the active alkaloids in the plant so it could be absorbed more readily. The only member of the Burke & Wills expedition to survive, John King, admitted that it was chewing the Pituri that enabled him to survive. He said that by chewing the Pituri with the Aborigines he met, he became “perfectly indifferent to his miserable conditions”.

Besides being a reliever of hunger and thirst, the Pituri is also an hallucinogenic. Only the elders of a tribe were allowed to chew the leaves and this obviously helped them maintain their position within the tribe. Under the influence of Pituri, they claimed they could communicate with the spirits of their ancestors and were able to forecast the future. The plant does not grow in many areas of Australia and appears to be common in the south-west where Spinifex grows and is rare in the east so it became an important item of trade. Another way of use was to drill a small hole in the trunk, pour in some water, plug it and the following day it would become a strong liquor.

Emus were an important source of food so leaves were placed in a small dammed-off section of a waterhole and the rest concealed by a brush fence and the emu would become intoxicated and walk around in circles which would then make them very easy prey to catch. There are conflicting reports as to whether the poisoned emu’s stomach was eaten but the records show that humans can drink the affected water without ill effects, if not immediately then within a day or so. Other animals and birds were also captured by this method. The leaves are known to be particularly poisonous to stock and a few mouthfuls will kill an adult cow. The toxins are known to be nicotine or nor-nicotine and concentrations vary between plants. It is considered a narcotic plant in Queensland but is rarely used in the Northern Territory.

This bush reminds me of another plant found in India which has similar properties. The Trichopus zetlanicus ssp. travancoricus belongs to the family Trichopodaceae and is a rare, herbaceous, perennial and rhizomatous wild plant which is endemic to the Agasthyar Hills of Western Ghats (Kerala). Among the “Kani” tribes of Kerala, Trichopus zeylanicus is known as “Arogyappacha”, meaning green health and vitality. The tribes claim that one can go for days without food and still remain energetic and even go on performing very vigorous physical work or exercise by eating a few of the fresh fruit of Trichopus. They also claim that to remain healthy, agile, young and resistant to various diseases or infections, one should consume the fresh fruits of “Arogyappacha.

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The way to dry Pitaya is very simple. Peel the skin and slice in ¼” thick slices and place on a wire rack so the fruit does not rest on a tray (the wire rack is very important). This helps the heat to circulate around the top and lower part of the fruit and not stick to the tray. Place the trays in the oven at 90ºC for 12 -15 hours – do this overnight so the kitchen is not being tied up. Once the slices are dried you can bag them in plastic bags. They are now ready to be saved or sold to the public.

This system allows the Pitaya to last for many months. You can put 3 racks at a time in your oven so if you have 20 slices per rack you will have a large finished product – 60 slices per night. If the fruit is not marketable because of cracks or production of fruit comes all at once and it cannot all be sold fresh, drying gives you the option of selling in that form. Drying improves the flavour considerably. This is because the water evaporates and you are left with a very sweet tasting fruit as the sugar remains in the dried fruit.

If you have dried red pitaya and have eaten in abundance, do not be alarmed if the colour of your stool becomes red as this is normal, much like when you eat beets. Most of the red coloured fruits are filled with antioxidants which are good for your health (pomegranate, beets, watermelon, tomatoes, berries). If you go to the section of photos in our `pitaya groups’, look in my folder of pictures. You will see how I have prepared the pitaya for drying or you can go to my website: www.edvaldivia.com

Hope you are successful and soon we will see more dried pitaya in the markets all year round.

Authored by: 

Edgar Valdivia from California

Sourced from: 

Sub-Tropical Fruit Club of Qld. Inc Newsletter October – November 2007

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Having read Bob Baxter’s article on Pinto Peanut in the last newsletter I was prompted to submit the following to share some of my experiences with this plant. I have been using Pinto Peanut on my property for a number of years, my most recent planting of seed being in September 1999.

The seed is quite expensive ($15 kg in 1999) especially if you are planting large areas at the suggested sowing rates. My experience with direct sowing is that seed is slow to germinate, up to three years in some cases, and with a low germination rate – maybe rodents took the seed or maybe they just dried out, as I do not irrigate. Best time to plant is spring-summer in SE Qld, all year round in the tropics. Seed needs to be planted 2-3 cm deep, recommended sowing rates are lower than Nutri-Tech’s suggestion at 10-20 kg hectare.

This summer, having established a few vigorous areas of the plant, I experimented with transplants. A small section of plant with roots attached was potted into a 50mm pot, kept shaded and well watered until re-established (a matter of weeks) then transplanted to the new location. Success rate has been in the order of 70- 80% and probably would have been higher had we not had such hot dry conditions, I will be planting out more plants in late summer when (hopefully) the temperature has dropped a little and the rains are more regular.

I would recommend anyone wanting to establish this wonderful plant should obtain a small quantity of seed and try planting (1) in situ, (2) in a prepared seed bed (maybe under shade cloth or netting to deter rodents) and (3) in pots (again under cover). Once established after 1-2 years, transplant to other areas.

Best source for seed would be Primac or Grow Force, an information sheet I have from Seed Grain & Biotechnology Australia has a Qld contact of Paul Hinder – Phone (07) 5485 2425, Fax (07) 5485 2471.

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Phosphonic Acid Injection for Phytophthora and other root diseases was compiled by Ted Newton from a talk given to the Sub-Tropical Fruit Club of Qld by Gus Gorissen of Chemjet Tree Injectors. website:  http://www.chemjet.com.au
 

History of the Chemjet tree injector

The company Chemjet started in the early 1980s. We had an avocado farm in Caboolture. A tree would be green one day, and yellow the next. The DPI confirmed that there was phytophthora on our place. Phytophthora is a fungus soil disease spread by feet – humans, birds, anything – and it’s all over the world. Overuse of pesticides in the past killed good bacteria along with the bad, so now the only way to control phytophthora is to treat it with fungicide. Our challenge was to get the fungicide into the tree. There were trees with no leaves left, so spraying was not an option. So the DPI suggested that we could inject it into the tree. We drilled a hole in a tree that we had been ready to take out and put in some fungicide using veterinary injectors. It worked; in three to four weeks the tree had new life and in six months was fully restored. However, with five thousand trees, injection using veterinary injectors had practical limitations. This led to the development of our first prototype injector, with a spring-loaded plunger. Over the years it developed into the little machine we sell now all over the world. It is a simple gadget and it lasts forever. It is also environmentally sound as each injection uses only 20ml of fungicide. With spraying, it’s proven that just ten percent of the fungicide is effective and the rest is wasted. The leaves do not absorb fungicide that is applied by spraying as effectively as they do when it is delivered by systemic injection.

Facts about phytophthora

Phytophthora stops the feather roots taking up moisture and nutrients. It is often thought that the tree needs nitrogen or something else. Often it doesn’t need anything; all it needs is a healthy root system. If you have a healthy root system, you can do with half of the nutrients that you have applied. The tree will look after itself, and the fruit will tell you if other nutrients are needed. Prevention of phytophthora is the key. Phytophthora affects tree health and when a tree is sick, every disease it gets hits hard. It will affect the size and numbers of your fruit. If you wait until you get that yellow colour on your leaf, you’re too late because you will lose your crop. If you have just one or two trees in your orchard with phytophthora, then it is in your place and you will spread the disease as you walk between healthy and infected plants. It is better to prevent it by injecting your trees at least once a year and you can be sure that you will keep your crop for that year. Often it is lack of water that has transferred the fungus through the soil. There is a way of measuring phytophthora in your root system. One way is to take all the dirt under the tree away, and cover the area with newspapers. Under the newspaper you will find new growth. The roots should be pure white. As soon as they show brown, that’s phytophthora. Phytophthora is in every agricultural crop. They spray for it, in potatoes, strawberries, and many others.

Other types of injectors

There are some other injecting machines around. Some have developed a system where the fungicide is shot in under high pressure. When you shoot it in under pressure, you can imagine what happens; you blow a hole in the tree. Just as when you get a splinter in your finger, nature responds by sealing it off, so fungicide fired into a tree under high pressure does not get taken up and is wasted. It won’t go anywhere, because the cells identify it as a foreign object and close it off and leave it there. Don’t be fooled by the idea that if you pump the fungicide in quickly and seal the hole to stop it running out, that it will be taken up over time. That is not the case. The fungicide has to be fed into the tree’s system under low pressure, 35 psi, otherwise capillaries can be damaged.

The fungicide

The fungicide is phosphonic acid, commonly known simply as phosphorous acid. Sometimes it is referred to as phosphonate. It is important to distinguish it from phosphoric acid which is a different chemical with a range of commercial uses such as rust and scale removal, and in dentistry. In diluted form it is an additive (E338) in carbonated beverages to give them a distinctive cola flavour. To be certain you get the right one, it is recommended that you buy a recognised brand of the fungicide from a retailer of gardening or agricultural products, ensuring that the label on the product specifies its use for the treatment of fungal root diseases in plants. When you read the labels of the various fungicides, bear in mind that all those manufacturers are aiming for volume use. Very small portions of their labels, if any, will provide guidelines on injecting, as they all want you to either spray the chemical or trench it. That is not necessary at all.

Injecting trees using the Chemjet tree injector

We can inject trees from as little as 50 cm (2 inches) diameter. On a young small tree less than 50 cm (2 inches) diameter, you may brush diluted fungicide on to the stem where it has a green surface and it will be absorbed. You may do this until the tree gets to a size when you can start injecting. The fungicide should be diluted according to the instructions on the label, but usually the ratio is about 25% fungicide to 75% water. When you inject a tree, you drill a hole, making a wound that takes time to heal. Not every tree is the same; one tree will be able to take up fungicide fairly quickly while another is unable to do that as fast.  In a young healthy tree, you need only one injector, because it will spread around and cover the whole tree. Stay away from the branches of young trees. If you drill a hole in a small branch, you may weaken the tree and it may snap. More injectors are needed on larger trees. Step out the canopy diameter of the tree, and the rule-of-thumb is that for every metre of canopy diameter, you put in 20ml of fungicide. Each injector holds 20ml of fungicide so this will determine the number of injectors you will need for that tree.

Drilling the holes

Always drill injection holes into fresh wood; if the sawdust is dark, you are drilling into old wood. The wood (the sawdust) should be white on the inside. If you drill into old wood, there may be a cavity inside and the fungicide will not be taken up. When you don’t drill deep enough, you don’t have enough space in front of your nozzle. You need surface area around the hole for the fungicide to penetrate the wood. Capillary action is better as you drill deeper. Also, it is better to drill at a downward angle. If you go in horizontally, you are likely to reach the core wood, whereas if you drill at an angle, you will stay in the sap wood. It is the sap wood that takes up the fungicide. You don’t have to do anything with the hole; being small, it heals itself.

How fungicide injection works

The fungicide goes into the sap flow and the leaves of the tree, photosynthesises with sunlight, then goes back through the sap and settles into the root system. There is where it stops the phytophthora going into the feather roots. It goes up, comes down, and will cover that particular area where you have injected. With growth rings, the phosphonate will not spread laterally; it will go up vertically. Then it comes down and it settles in that particular root system on that particular side of the tree. In the end it’s a matter of judgement. Particularly in drought conditions, the more roots you can create the more chance the tree will survive. Using the canopy ‘rule-of-thumb’ described earlier, you divide that around the trunk. You don’t have to put it all into the trunk. You can put it into the branches coming from the main trunk. However, if you drill into too small a limb, it burns because it overdoses. For example, a limb of 100cm (4 inch) diameter or less could be too small. Sometimes, in 24 hours the tip of the leaves will turn brown. It means that you might have overdone it a little bit, but it is an indication that the fungicide is at least in there. That’s good; the leaf will fall off and quickly re-grow and the tree will be protected for the next 12 months. The uptake on the side of a tree away from the sun may be a lot slower than on the side facing the sun. Therefore individual injectors are needed because you have to cover 360 degrees around the tree to cover the whole root system. Stay away from a tree when it is flowering. Also water it well when flowering. It will develop the growth cells at that particular time. If you don’t water, it won’t have the growth cells when it gets water later on, and it will split.

Treating already sick trees

You need to inject sick trees at least twice a year to get them back to where they should be, and then you may be able to get away with once a year after that once the tree is fully restored. There is a way of measuring fungicide present in the soil, but it is a very technical process and you would need to ask for professional help. For small growers, that might be too costly. The simplest way is to inject once a year for healthy trees, and twice a year for the sick trees.

Using avocadoes as an example

With avocadoes, first you have your fruit-set. After your fruit-set, you get your new shoots coming out. As soon as the young red leaves turn into green, then your root system starts developing. That is the time you start injecting because all the new roots will develop from that month on, and you want them protected. That is your first flush. Your next flush – the summer flush – will be in January, so if you have sick avocado trees you will give them another injection then. If you don’t see much improvement, inject them again before winter time. The good thing about injecting is that provided the injector containing the fungicide doesn’t fall out, which it won’t if you put it in properly, then once it is empty the fungicide is in the tree and no other place. If you spray it on, you have to wonder how much of it will be taken up, and you have no idea. When you do it with this injector, it’s guaranteed to be in the tree. It also pays to keep up with developments from DPI. They will let you know latest information, for example, they are currently researching a theory that just one injection eight weeks before flowering will protect avocadoes from phytophthora for the whole year. However this research has not yet been finalised.

Further information

Comprehensive information on the Chemjet injector and its uses may also be found on the company’s website at www.chemjet.com.au  A product brochure in PDF format may also be downloaded from this site.

Members’ questions

Member: Can you inject anything other than phosphonate?

Answer: Yes. Companies have developed a systemic insecticide – Dimethoate – you may already be spraying it in your orchard. That is for borers and similar pests. However because it is systemic, you have to be careful that there is no residue coming in to your fruit because you injected at the wrong time. But in the off-season, particularly with citrus where you have problems with borers, by all means, inject it.

Member: What about a Neem extract? That should be perfect for it.

Answer: Exactly. In America they did very successful trials of it.

Member: Does this systemic fungicide find its way into the fruit?

Answer: No – it won’t go into the fruit; it affects the roots, and therefore the health of the tree. That will improve the fruit.

Member: When is the best time to inject?

Answer: The best time is in the morning before the day heats up. You also put all the injectors in at once, because the holes ‘communicate’ with each other.

Member: The barrel of the device has a graduated scale for measuring the phosphonate. Do you always use 20ml?

Answer: Yes, always 20 ml. The scale is there because in the early days we used to use coal tar to dwarf the tree, to stop it growing too fast. That was an ICI product, and the DPI in Nambour discovered that with 10ml injected each year, you could dwarf them and slow down all the energy going into growth. However ICI never registered it for injecting; they said you have to pour it or drip it on.

Member: How can you tell if a tree has phytophthora?

Answer: You can see the yellow nerves in the leaf – that’s an indication.

Member: Have you experienced phytophthora in trees other than avocadoes such as mangoes?

Answer: Yes. We do mangoes, citrus, chestnuts and ornamentals – they all suffer from phytophthora. It is often said that they are blown over by wind. They do that because they have no roots left. The only state in Australia that recognises die-back is Western Australia and they do something about it. We suffer it everywhere. The Sydney Harbour Trust did a full study of it because of gum trees that fell over. If you have an unhealthy tree, borers and other insects have a feast. They affect the whole growth cycle of a tree. The roots are not expanding. Years ago I know we had roots on trees that went looking for water. Nowadays they say that if there is no water the roots don’t go looking for it, but they used to. They would go under asphalt, under anywhere to find water. But if they haven’t got that root system, they can’t do it.

Member: So how long does the phosphonate take to go in?

Answer: Temperature is a factor. If the temperature is low, there is no respiration in the tree; respiration is the amount of water that is flowing up and evaporating through the leaves, and that’s what it’s dependent on. If there is not much evaporation, then there is very slow uptake. The tree is just saving its energy for other times of the day, when it will be growing. It can take anything from 25 minutes to 2 hours.

Member: There are a lot of beneficial fungi. What happens to those when the phosphonate goes down to the root system?

Answer:  You are only putting in a minute amount compared to spraying or trenching. Your soil fungi actually do need phosphorous in small amounts, so this may actually help them.

Member: If we use injectors, does that mean we can grow avocadoes in flat, poorly drained country, because we are able to combat the phytophthora?

Answer: Possibly! Actually the avocado tree was originally a swamp tree. It came out of the Guatemalan rain forest.

To inhibit the spread of Phytophthora the following should be adhered to:

Sanitation of tools and machinery – tools must have all traces of soil washed off then be regularly drenched in a solution of disinfectant. (A solution of one per cent bleach is sufficient for disinfecting machinery.) When planting several plants, disinfect tools in a portable container of disinfectant before and after planting each one.

Boots and tyres – soil clinging to boots and tyres is a common vector in transporting Phytophthora. To limit the spread of this fungus, ensure all soil is scrubbed clean and the surface is disinfected (using a one per cent solution of bleach, or a 70 per cent solution of methylated spirit. Using disinfectant according to the manufacturer’s directions is also suitable.)

Infected vegetation – Phytophthora can persist for many years in the dead organic tissue of any trees it has infected. Infected vegetation must be disposed of carefully. Never woodchip any vegetation suspected of being infected by Phytophthora. Prevention and limitation of the spread of Phytophthora is the most effective means of control (Royal Botanic Gardens Trust 2007).

Sheryl:  Many Thanks to Ken & Muriel Webb for hosting this field trip at their place.

Terminology explained:

Phosphonic acid: Phosphonic acid is one of two forms of an organic compound commonly known as “phosphorous acid”. See the explanation below under “Phosphorous Acid”.

Phosphoric acid:  Phosphoric acid is a mineral (inorganic) acid having the chemical formula H₃PO₄. It has a range of industrial uses including: rust removal; a food additive in processed beverages such as cola drinks; an etching solution used in dentistry and orthodontics to roughen the surfaces of teeth where dental appliances or fillings will be placed; electrolyte in some fuel cells; an industrial-strength cleanser, and a pH adjuster in cosmetics and skin-care products and in hydroponics. It is not to be used as a fungicide.

Phosphorous Acid: Phosphorous acid is a compound generally described by the formula H₂PO₃, although it is an organic compound that exists in equilibrium and reacts as if its molecule has more than one structure. One form is called phosphorous acid, and the other phosphonic acid. As an aqueous solution, the acid is trunk-injected or foliar-sprayed to control a variety of microbial plant diseases such as phytophthora, dieback/root rot, and downy mildew. It is also used to prepare phosphite salts used for similar applications. Phosphorous acid and its salts are more toxic than phosphoric acid and should be handled with caution.

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The perilla genus has at least 6 species that have been used by man. Their area of origin in Asia extends from India to Japan. Perilla is an aromatic, fast growing annual 50cm to 150cm tall, resembling Coleus in appearance, and large leafed basils, to which it is related. Two lipped flowers can be white, pink or lavender-purple, forming in leaf axils and terminal spikes. The plant has a very bushy canopy of opposite leaves forming on square stems. Leaves are ovate to 15cm long, and the margins are soft toothed and may be indented and frilly. The herb is a traditional oriental flavouring, particularly in Japanese cuisine, where it is used as readily as we use parsley. The leaves are highly aromatic and really cannot be compared to the smell of any other herb. The flavour is slightly sweet and spicy with a note of mint. Perilla’s aroma and flavour take a while to be appreciated. Leaves are eaten raw, cooked, salted and pickled, or used as a garnish. Young green leaves, particularly of green perilla are essential for sushi. Purple perilla leaves give a vivid colour and flavour to the traditional Japanese sweets and umebashi pickled plums. Perilla is also used in pickled ginger, Chinese/Japanese artichokes (which are an attractive gourmet root vegetable, see pages 84, 269) and raw fish dishes like sashimi. Leaves are cooked in tempura batter and used to flavour bean curds. Perilla seeds may be sprouted, like alfalfa, added to any dish or used as a garnish. Flowers make a dainty, edible, decoration on a dish. One of the components of the volatile oil extracted from perilla, perilla-aldehyde, can be made into a sweetener, said to be 2000 times sweeter than sugar, with very low kilojoules. This sweetener has been used as a substitute for maple sugar or licorice in processed foods, and is utilized in processed foods and tobacco. However, an antioxime of perillaaldehyde, is considered too toxic for food use, although, it is used in minute amounts in flavouring sauces, toothpaste and confectionery. Analysis of perilla’s anti-microbial properties has been documented to have over one thousand times the strength of synthetic food preservatives. Perilla is grown as an oil seed crop from Japan to northern India. The oil comprises up to 51% of the seed’s weight. The oil is used for culinary purposes, similar to linseed oil, and also has industrial application in paint, printing, and paper manufacture. The natural red pigment called shisonin is used in food processing as a colourant.

Sheryl: I recently visited Melbourne and observed this plant growing in my friend’s garden and brought back some seed so hopefully I can share it with you if I am successful in propagating it. It was growing exceptionally well (weed said my husband!) My friend and I both love Japanese cuisine particularly Sushi so do go looking for it.  Nice photos at:  http://www.plantnames.unimelb.edu.au/Sorting/Perilla_Gallery.html

Wikipedia says:  Perilla is a genus of an annual herb that is a member of the mint family, Lamiaceae. In mild climates the plant reseeds itself. The most common species is Perilla frutescens var. japonica or shiso which is mainly grown in India and East Asia. There are both green-leafed and purple-leafed varieties which are generally recognized as separate species by botanists. The leaves resemble stinging nettle leaves, being slightly rounder in shape. It is also widely known as the Beefsteak plant. In North America, it is increasingly commonly called by its Japanese name, shiso, in addition to being generally referred to as perilla. Its essential oils provide for a strong taste whose intensity might be compared to that of mint or fennel. It is considered rich in minerals and vitamins, has anti-inflammatory properties and is thought to help preserve and sterilize other foods. In Nepal and parts of India, it is called silam. Its seeds are ground with chilli and tomatoes to make a savoury dip/side dish. In North America one of the purple varieties is sometimes known as Purple Mint, Chinese Basil or Wild Coleus (although it is not a mint, basil or coleus).

Chemistry

The essential oil extracted from the leaves of perilla by steam distillation consists of a variety of chemical compounds, which may vary depending on species. The most abundant, comprising about 50–60% of the oil, is perillaldehyde which is most responsible for the aroma and taste of perilla. Other terpenes such as limonene, caryophyllene, and farnesene are common as well. Of the known chemotypes of perilla, PA (main component: perillaldehyd) is the only one used for culinary purposes. Other chemotypes are PK (perilla ketone), EK (elsholzia ketone), PL (perillene), PP (phenylpropanoids: myristicin, dillapiole, elemicin), C (citral) and a type rich in rosefuran.

 Perilla oil is obtained by pressing the seeds of perilla, which contain 35 to 45 percent oil. In parts of Asia, perilla oil is used as an edible oil that is valued more for its medicinal benefit than its flavor. Perilla oil is a very rich source of the omega-3 fatty acid alpha-linolenic acid. As a drying oil similar to tung oil or linseed oil, perilla oil has been used for paints, varnishes, linoleum, printing ink, lacquers, and for protective waterproof coatings on cloth. Perilla oil can also be used for fuel.

The oxime of perillaldehyde (perillartin) is used as an artificial sweetener in Japan as it is about 2000 times sweeter than sucrose.  References:  Refer wikipedia on the web

NB:  Perilla ketone is toxic to some animals. When cattle and horses consume purple mint (of the PK chemotype) while grazing in fields in which it grows, the perilla ketone causes pulmonary edema leading to a condition sometimes called perilla mint toxicosis.

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In July, John issued the challenge “I want a really BIG pepino patch this summer”, and so I got to work. We’d had few straggly pepino plants around, but they weren’t given any special treatment, were semi-shaded, and had only produced a few small fruits, which were promptly eaten up by magpies.

I decided to do some research about growing conditions, and found that the pepino (Solanum muricatum) is native to temperate climates, originating in the Andean regions of Colombia, Peru and Chile. Surprisingly, the plant is not known in the wild, only in cultivation, so no-one really knows its origins. It is grown commercially in New Zealand, Chile and Western Australia. Fortunately the pepino is a hardy plant and can grow at altitudes ranging from near sea level to 3500m, although it does best in a warm, relatively frost-free climate. This seemed to suit our conditions – our vegetable patch is at the highest point of our 5 acres, and hardly gets touched by frost. In any case, it seems that they will survive a short period of low temperature of 27 to 28° F, but may lose leaves.

I forked over a patch in full sun about 3 x 2 metres and worked in some well rotted compost and just a few handfuls of Organic Extra. Our garden is all organic, and this is the standard treatment for my vegetables. I didn’t overdo the fertiliser, as I wanted to avoid too much vegetative growth. The patch was then left fallow while I propagated the plants.

With its woody stems and fibrous roots, the Pepino is very simple to propagate vegetatively from cuttings. I just ripped up some pieces – some of which had roots and some not – treated them with rooting hormones, potted them in some good free-draining mix, and placed them in our shade house. In a few weeks they were flourishing – each piece had grown to a strong plant with vigorous root growth.

I planted out 10 plants into the patch in late August, so they would have plenty of time to grow and ripen during the warm summer months. I gave them a spacing of about 40cm, and mulched well to suppress weed growth. The whole vegetable garden gets watered frequently by overhead sprinkling, and over the next few weeks the pepinos responded with rapid growth. Apparently they are sensitive to moisture stress, as their root systems are quite shallow.

The plants started flowering well but seemed slow to set any fruit. Back to the Internet! – where I found that they will not set fruit until the night temperatures are above 65° F. Before long the fruits were forming, alas, just as the first few ripened, John was headed off to the USA for 2 weeks on a business trip. He managed to try the first one, but over the next fortnight they just kept rolling in, and all the neighbours benefited! Most of the fruits were very large, as big as a good sized orange, and sweet and juicy. Luckily there were still plenty when John returned, and he went straight off to “his” Pepino patch and filled a large bucket or two. 

We have had virtually no problem with pests and diseases. Occasionally a creature (probably a rat) has a go at a fruit – usually the ripest. Apparently pepinos can be affected by many of the diseases and pests that affect tomatoes, such as bacterial spot, anthracnose and phytophthora, spider mite, cut worm, fruit fly and leaf miner, but we have not had any trouble with these. 

Despite the possibility of pest attack, we avoid the temptation to pick the pepinos greener, because the best flavour is when they are fully sun-ripened, when they compare favourably with a cantaloupe or honey dew melon. John grabs the fruits straight from the plant as a thirst quencher, and can be spotted in the garden with juice dribbling down his chin, but I think they are nice chilled and eaten like a melon.

Our pepino patch has been a great success, and I recommend that everyone grows at least a few plants. To top it all off, yesterday I noticed pepinos in the supermarkets selling for $2 each – and not as big as ours! I guess that means we’ve produced a couple of hundred dollars’ worth already!