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 In some of our supermarkets recently you may have seen a large knobbly bulbous root about 12cm in diameter called Celeriac and never having tried this vegetable before, I bought one home and studied the books to see the various ways of preparing it.   It looks much like a turnip but with a rougher skin.   It is a winter vegetable and the fresher it is the paler it will be.

In its raw state it has rather a mild celery taste which I liked.   I then cut it into julienne strips and blanched it in hot water with some lemon juice added to retain the colour as it will discolour very easily.    Add it to a salad for a different flavour as you would water chestnuts, gingko nuts, capers, anchovies or cornichons.  The French grate it or just-blanch it then mix it with mustard mayonnaise to produce celerirave a la remoulade.   It can be added to soups or stews and the leaves can also be used in salads.   I tried it boiled and steamed, but like turnip, I prefer it to be mashed with a little butter and other condiments added.    Try it stir-fried or baked in a cheese sauce. 

Celery and Celeriac (members of the Umbelliferae family) come from the same source – Apium graveolens  – and both are bred from the original wild plant found in the Mediterranean area with other wild forms of celery found in Europe, Asia Minor and between the Black and Caspian Seas and reaching towards the Himalayas.   Although it was mentioned in Chinese writings during the fifth century, it took another 1200 years before the gardeners of Italy, France and England started to tone down it s strong flavour through selective breeding and it was during this time that Celeriac was developed as one of the improved varieties.  It was a common vegetable around 1700 and is a standard winter vegetable in Germany and eastern Europe.      

Propagation and Growing Conditions:    

By seed – have never seen seedlings around.    In sandy soil, the bulb won’t develop, so it is best grown in heavy moisture retentive soils.    They are gross feeders.  Sow seeds in spring 40cm x 40cm apart and harvest in autumn.   Like other plants in this family, it has a low and slow germination rate so use a generous amount of seed and hasten things along by placing the seeds on wet paper towels in a shallow plastic covered tray for a few days and keep in a warm spot (not the sun).  When they sprout, mix with cornmeal or sand for easier handling and sow immediately just below the surface.   Cover with wet hessian and don’t allow to dry out – remove when plants start to grow.   Don’t plant deeply as the bulb must sit on the soil and not get buried.     Those in warmer climes can also sow in autumn.   120 days to maturity.  During the growing period, draw soil away from the swelling bulbs and tear off any side-shoots which may appear at the base of the plants as the crown needs to be exposed.    Liquid fertilize weekly at this stage.  A fortnight before the roots are to be lifted, the soil can be hoed up to the foliage to cause the upper part of the root to become blanched. 

Varieties:

White Alabaster:(this is a newer variety that produces more uniform, larger bulbs than Prague). In overseas catalogues, there are also listed Apple, Claudia, Early Paris, Globus, Jose, Iram, Large Smooth Prague, Marble Ball and Tellus.   

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In Australia, the winter months are June, July and August.

Never use any oils on your trees in winter as you will kill the tree. Apply Envy or equivalent to trees susceptible to frost. Spray for Bindi before August – use a herbicide or mix a cup of common salt with a cup of vinegar and apply with a paint brush or roller. Prune all deciduous trees and use for cuttings eg. grapes/figs/jujubes/mulberries – late winter is better as they come away much quicker. Bring the cuttings along for the raffle table and put a name tag on them. To prevent the formation of frost under frost sensitive trees, remove the mulch although Mary King has found that when they used dead wattle leaves, it did not attract the frost.  Rocks and stones also help to store the sun’s energy especially if covered with black plastic over the rocks. Remove after the last frost. If plants become frost-burned, don’t immediately cut off the affected parts as they give protection. Apply tree paste to trunk but not to green wood.

Peter Sauer uses a Potassium soap spray 3-4 times throughout the winter to control pests – this adds a significant amount of Potassium to the trees. If you’re using microbes on your fruit trees: flower emergence – spray foliar microbes 15mls/L with 2mls/L high calcium + 1ml/L Boron to enhance fruit set. Wait 21 days and repeat 2 more times. Spraying to be done to runoff of leaves.

Authored by: 

Sheryl Backhouse from various sources and checked with other members

Sourced from: 

STFC Newsletter June – July 2006

Date sourced: 

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I hope to be able to explain in three easy-to-follow steps, how to make a quality fruit wine you can be proud of. You will then be on your way with a new art form, like when an artist paints his first masterpiece, or when a chef creates his first great meal. As with any art, you may experiment around some basic principles, with some failures, but with time and experience, failures will rarely occur and most of it will be success.

Step One  Prepare the fruit. Take over the kitchen. You will need access to a stove, a kettle, a freezer, a blender, a sink, and a good glass of wine (of course to remind you of what you are aiming for). Prepare two kilograms of the fruit (I will not be covering the creation of vegetable, flower, herb, honey or grape wines – let’s learn to crawl before we run). Do not remove the skin unless it is usually inedible – the exception being bananas, as banana skin can be used in wine, but we don’t usually eat it. Remove stones and pips – it is easy to do so. If the fruit has larger stones or seeds that are not easy to remove, that would be broken up by the blender, then the fruit needs to be crushed by the potato masher rather than put through the blender. If the seeds are either very, very small, such in many berry fruits, or have been removed completely, then the two kilograms of fruit is best put through a blender. Then, in 2kg lots, freeze them in the freezer. The ice cream tubs come in very handy for this process. Freezing the fruit brings out the extra flavours and helps break down some cell walls in the fruit. The fruit, now frozen, can be stored until it is convenient to start the wine.

Clean out a twenty-litre esky with some boiling water. It does not need to be completely sterile. However, if you prefer to be absolutely sure, then a small quantity of sodium metabisulphite and warm water wiped around the inside of the esky will do the job. Put the two-kilogram block of fruit in the esky and leave to defrost.

Into a large saucepan, that is able to hold at least ten litres, put one kilogram of sugar (1.5kg for a medium wine, 2kg for a sweet wine), the tea from six teabags or half a teaspoon of red tannin powder, and three litres of boiling water from the kettle (this is quicker than trying to bring the water to the boil on the stove). Bring it all to the boil, then pour over the defrosted fruit in the esky. Stir quickly, then replace the esky lid and leave to cool for twelve to twenty-four hours. The heat from the boiling water will effectively sterilise everything inside the esky without cooking the fruit. Don’t forget to clean out the stockpot and clean up the kitchen. Your future expeditions into wine making may depend on it!

Step Two    Your wine / sugar mixture (must) is now ready to start fermenting. Yeast can replicate and grow by breaking down sugar into alcohol and carbon dioxide (CO₂). It does not need oxygen (O₂) to complete this process. This is called an anaerobic process. If oxygen or air is allowed to get to the wine, oxidation can occur, whereby, alcohol combines with oxygen to create acetic acid (vinegar). There is a bacterium called acetobacter that carries enzymes that rapidly promote this process. The acetobacter looks like a white scum on the surface of your wine or beer. It requires oxygen to survive.

When wines or beers are fermenting rapidly, a large amount of carbon dioxide (CO₂) is produced, which is heavier than air. Therefore, a thick layer of CO₂ is created above the fermenting wine or beer, excluding any oxygen. Therefore, during the rapid fermenting process, at the beginning, oxidation of your wine or beer is very unlikely to occur, and you do not need to have it in an airtight container fitted with an air lock. When the fermentation slows down, this is the danger time, as the layer of CO₂ above the wine or beer is not as dense, oxygen can get to the surface and oxidise the alcohol to vinegar, particularly in the hot Queensland climate. It is therefore important to reduce the amount of air space above your fermenting wine or beer when the fermentation process slows down. This simple understanding of how the fermentation process works will probably get rid of a very large number of people having disasters.

When we add the yeast, we want fermentation to start quite rapidly to create that CO₂ layer. To ensure this rapid start, some people create a yeast starter bottle where they add a small quantity of sugar in a sterile bottle and water with the yeast the day before they are going to add this to the wine. DON’T BOTHER! The wine will still be warm after twenty-four hours in the esky and addition of dry yeast will still create a very rapid fermentation, so, add a small quantity of dried wine yeast, a teaspoon of yeast nutrient (available at local brew shops), and a teaspoon of pectolitic enzyme (pectolase). For most wine, the addition of the yeast nutrient is not absolutely necessary, however, if you embark on vegetable, flower or honey wines, the addition of yeast nutrient is essential. The addition of one tspn of tartaric or citric acid will certainly help the flavour of wines that are based on non-acidic fruit, in particular bananas. The pectolase, in my opinion, is essential for most wines, unless you are absolutely sure that the fruit you are basing your wine on does not contain any pectin. Pectin is required in jam making, making the jam set. If present in wine, it creates a haze that is very difficult to get rid of at a later date. Therefore, the addition of a pectolitic enzyme, that destroys pectin, at the beginning of the fermentation process, ensures you are likely to have a clear wine at the end.

Which yeast? There are approximately ten different wine yeasts, all with different qualities. I will not go into every wine yeast here, but Gervin produce an excellent range and the quality is superb, however, they are difficult to get hold of in Australia. The licensed importer is in WA, however, most of the yeasts can be purchased from your local brew shop, although, not under the Gervin name. Once the yeast nutrient and pectolase are added, stir them twice a day for the next seven days. Note: Use a large wooden or plastic spoon, or alternatively, a stainless steel one that has been sterilised with boiling water or through the microwave. This is quite important.

Step Three    For the past seven days, some part of your house has smelled like a brewery. Well, now it’s time to get a bit messy. You need a 10 litre plastic bucket that has been sterilised with some sodium metabisulphite. Over this, drape a large nylon straining bag. You can make this from nylon mesh similar to mosquito netting, or buy it from you local brew shop. Pour your brew into the straining bag, lift up the edges, and gently squeeze out as much of the liquid as you can into the bucket. IMPORTANT: Your hands need to be as clean as possible for this stage, preferably cleaned in a weak sodium metabisulphite solution, or better still, put on some plastic gloves and wash those in a metabisulphite solution. There are probably a hundred different ways that this messy stage can be made slightly less messy, but why should I spoil your fun. Just keep the solid particulate matter inside the nylon bag and the liquid matter in the bucket. When you have squeezed out as much as you can and your hands and arms are aching from the process, put the nylon bag and solid matter aside.

The liquid now needs to go into sterile fermenting vessels, that is, some concentrated metabisulphite should have been in the container, shaken about and left for a short time. 3L fruit juice containers are ideal for this purpose, and the liquid you have should fill two of these almost exactly. If it doesn’t, top up with water to approximately 3cm from the top. Fit a rubber bung and air lock, also sterilised by soaking in metabisulphite. Put a small amount of metabisulphite solution in the air lock and leave to finish fermenting, which will take approximately two to six weeks, depending on the time of the year. After three weeks, whether it has finished fermenting or not, the clearer wine at the top needs to be siphoned off, using a sterile siphon tube, into another sterile fermenting vessel. A 5litre glass demijohn is ideal. Alternatively, another 3litre fruit juice container and a 2litre wine or port flagon is adequate. (Anyone unsure of how to siphon the clear wine from one bottle into another, please give me a call.)

Some wines may now have finished fermenting and be quite clear and therefore are ready for bottling without further ado. Most wines will take a little longer than this to clear and you have to leave them in the fermenting vessels for anywhere up to six months, however, most wines will be clear within two months. There are various reasons why your wine may not clear, and it is probably best to seek advice from your local brew shop about using a clearing agent. For perfectionists who wish to have their wine absolutely crystal clear, a filtering mechanism may be required. However, for most people starting up, a very slight haze on the wine will not change the flavour much at all, and is quite acceptable.

Bottling: How to become very unpopular with the rest of the household in the middle of a summer’s night, (and oh so many people has this happened to), with exploding bottles and popping corks on a hot warm evening because they have lacked that great virtue, patience, and have tried to bottle their wine far too early. I could make this part very high-tech and very complicated. For those who compete at state or national levels it is complicated, especially when trying to make lower alcohol semi-sweet or medium wines. So, invest in a hydrometer and read the instructions. If the specific gravity of the wine is less than 0.995, and the fluid level in the air lock appears level and not popping, the wine is unlikely to ferment any further, and if it is clear, it can be bottled. If you are making a sweet wine and the specificity is as it is meant to be (more than 1.020), invest in a little, tiny capillary action vinometer that gives an approximate alcohol by volume measurement. If the alcohol by volume measurement with this little device is more than 18%, it is not likely to ferment any further and can be bottled if clear. Anything between these perimeters may need a little more thought. Happy brewing and remember, have fun! Experiment in small qualities and even the best chef can burn the toast.

 If you’re interested in making fruit wine, consider joining the Western Suburbs Amateur Wine & Beer Makers Guild. Meetings are usually held at the Graceville Croquet Club, Appel St. Graceville 7.30pm 1^st Wednesday of each month. Contact Tony Bilbrough preferably by email: tony@bilbrough.com.au   0415 032 285

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How wonderful it is to experiment with some of Queensland’s tropical and exotic fruits.  The joy from experiencing some of the fantastic tastes of the fruit itself and then wonder what flavour the wine will have.   Recently I have been experimenting with a whole new range of Queensland’s exotic fruits.  One of these fruits is the Yellow Mangosteen.  People may know of the Purple Mangosteen which does not actually grow in Brisbane, because it is too cold for this truly tropical fruit.  Many regard it as the best fruit in the world, and I am sure, those of you who have had the good fortune to taste it would agree.

The Yellow Mangosteen, however, is quite different.  The fruit is the size of a tennis ball and is bright yellow with a waxy skin.  The yellow pulp inside is made up of two parts.  The area under the skin is quite sour – almost as sour as that of a lemon, whereas the fruit pulp around the seed is much sweeter, perhaps comparable to a sweet grapefruit.  The fruit was clearly too acidic to attempt to make a dry wine.  However, the tanginess of the fruit acids lent itself ideally to make a sweet white wine.  My first effort last year did extremely well, winning a gold and a silver medal.  The bottle was completely devoured by other members of the club in the general tasting after the competition.  It is one of the simplest wines to make.

Simply skin the ripe fruit, remove the pulp from around the seeds until you have approximately two kilograms of Mangosteen pulp.  Bring to the boil three litres of water with two kilograms of sugar and four tea bags.   Pour this over the fruit pulp in a sterile esky and leave to cool for one day.  Then add a teaspoon of peptolitic enzyme, a high alcohol tolerant yeast, and a teaspoon of yeast nutrient.  Keep the esky covered apart from when you are stirring.  This should be done once a day for seven days.  Strain the wine in a nylon bag into two three-litre sterile fruit juice containers and fit air locks.  Ferment for another one to two months, then rack off or siphon off the sediment and put the wine into a 5 1itre demijohn, leaving to clear for another two months before bottling.

This wine clears on its own and very rarely needs any clearing or filtering.  It should be ready to drink within three months of starting to make it.  This is a truly delicious wine, but remember, moderation!

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The Agricultural Research magazine in November 2000 reported the findings of some interesting research in the USA, where a special type of kaolin clay (marketed as the product “Surround”), sprayed over apples and pears protected them from sunburn and increased yield dramatically, as well as keeping insect pests away.  The research was carried out by D. Michael Glenn, Gary J. Puterka and Michael E. Wisniewski .

Kaolin safe to ingest (in fact, it is often taken as an anti-nausea medication). The idea of spraying trees with kaolin was originally conceived as an organic method that would repel insects and prevent disease organisms from entering fruit, by putting a physical barrier over the fruit. However the research revealed another advantage.  Apples harvested from treated trees were an average of 17 percent larger than fruit from trees left untreated. Some types of pear trees yielded twice as many pears with no decrease in fruit size. Other trials revealed that using the kaolin improved the colour and raised the sugar content of Arizona-grown lemons, while grapes reached the desirable sugar content sooner than those left bare.

It seems that the specially processed kaolin coating reflects the heat-producing infrared wavelengths of the sun, as well as the burning ultraviolet rays. Keeping the tree cooler increases fruit yield and helps prevent fungus. Some of the research has also shown that kaolin-coated trees photosynthesized up to 30 percent faster than uncoated trees.

Kaolin also seems to be proving very successful against insects, as it seems they don’t like biting or crawling on a plant or tree covered with the kaolin dust. The researchers reported in their article that the kaolin seems to sticks to insects’ wings, legs, and mouth parts, causing them to leave to find a more favourable place to feed and lay eggs. They state that “In studies around the country, codling moths, apple maggots, plum curculio, leafhoppers, Japanese beetles, rose chafer, thrips, and rust mites—not to mention pear psylla—have fled whitewashed crops in search of greener pastures.” The white leaves also seem to make it harder for insects to recognise their favorite hosts. After several years of research trials, the product is proving effective against many types of insects.

The researchers reported that it is important to get good coverage of the crop with the kaolin product. They have investigated ways to improve kaolin’s ability to mix with water, so that it sticks better. Areas of low rainfall are particularly adaptable to this new technique, because in rainy areas the kaolin will eventually get washed off by rain.

Finally, another feature of the new product is its ability to reduce frost damage, because of the water repelling qualities of the kaolin coating. Leaves that are have less water droplets on them will not suffer as must tissue damage from freezing.

In summary, although the kaolin spray is still in the early days of testing, it appears that it can:

• control fungal diseases • control insect pests • prevent sunburn on fruit and nuts • prevent heat stress • increase yields • increase photosynthesis

• prevent frost damage

http://www.ars.usda.gov/is/AR/archive

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Paul Recher says that the vast majority of cultivars are pollen sterile so you must plant a cultivar that has pollen. I spoke to the President of the South Australian Rarefruit Association about the problem and he confirmed the same prognosis so I emailed Peter Young from Birdwood Nursery and here is his reply. “Pollination in White Sapote is critical and is the main reason for many good eating cultivars not being sold to retail as stand alone trees fail to crop. This is why we chose ‘Dade’ as it has good quality fruit and we have found it to be highly self fertile.  It is also a compact grower.  Varieties such as Reinike, Golden Globe, Candy, McDill and Denzler to name a few all need pollinating.  Varieties that are recognised as good pollinators for such varieties are Dade, Vista, Ortego and Vernon.  Lemon Gold that is also very self fertile does everything later than most cultivars.  It is a big tree, small fruit and although it’s good eating, doesn’t make a good pollinator or backyard tree.”  Sheryl: Some of the South Australians don’t like Dade

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Most people associate the word “Fruit” with succulent fleshy plant structures but botanically the concept is much wider than this. All fruits develop from a flower – the classification of which is based on which parts of the fertilised ovary expand in size. The fruit structures have evolved in various ways to enhance wide dispersion from the initial plant and improve the chance of seed germination. The basic classification of fruit types is:

 A.   Simple Fruits formed from a single ovary which may contain more than one seed.

 (i)   Fleshy fruit types – berries, drupes and pomes

 (ii)  Dry fruit types – legumes, follicles, nuts & capsules

B.    Aggregate Fruits formed from a number of ovaries in one flower fusing into a single fruit

e.g. strawberries, raspberries and blackberries.

C.   Multiple Fruits formed from several flowers having the ovaries fused into a single fruit

e.g. mulberries, pineapples and figs. Multiple Fruits can be difficult to visualise but if the fruit development is observed on the plant,  justification for the classification can be seen.

Fleshy Fruits

BERRIES have a fleshy pulp containing the seeds centrally with a thin skin often  coloured conspicuously to attract  birds and animals.   Typical examples are the grape and tomato but also included is the capsicum, carambola, mangosteen, paw-paw, passionfruit, roseapple, sapodilla, avocado (oily flesh) and banana (seeds very rare).   The citrus family are special berries called  Hesperidia the name coming from Hesper a Greek mythological character who had a citrus grove.   The skin (rind) is inedible and  the inside pulp has a high juice content but all family members are similar – typical of lemons and oranges etc.   The Cucurbit family are also special berries called  Pepos.  I think Pepois Spanish for “Gourd”  but all the family members have a hard leathery skin including cucumbers, chokoes, pumpkins and watermelons.

DRUPES are distinguished by containing a woody pit or stone which encloses one or occasionally two seeds.   Drupe is a Greek word for “Olive” but possibly the Apricot is a better example with its large amount of edible flesh.   Other fleshy drupes are cherries, peaches, plums mangoes and lychees.   Some drupes have almost no flesh and the inner seed is eaten – examples being the Almond and Pecan.   The coconut  has an external covering that is thick and fibrous which promotes floating in seawater but it is nevertheless a drupe.

POMES of which Apples, Pears and Loquats are examples are so called from the French word for Apple.   The base of these fruits contains the residual structure of the flower called the Calyx and the main fleshy structure we eat is called the Hypanthium which  surrounds the “core”  containing the seeds.  

Dry Fruits

LEGUMES of which beans and peas are typical develop a pod which splits down both sides when the seeds are ripe.

FOLLICLES of which the Macadamia is typical, split down one side of the husk to release the so-called “nut” botanically described as a Locule.  We crack this Locule to get at the seed typically called the Kernel.  

CAPSULES to my knowledge do not produce edible structures but a good example is the Poppy head which resembles a salt shaker when ripe.

NUTS are not common – the Acorn and Hazelnuts are good examples with their special “cap” and hard leathery skin enclosing one seed.  Most commercial so-called nuts (Almond, Pecan) are Drupes.

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Here in Manatee County, (Florida USA) we are favoured with a climate that permits a large number of tropical fruits, but these are variably sensitive to cold. This has to be considered before you decide what to buy for your location. It makes sense to buy a tree that would encounter a killing freeze about once in five years only if you are prepared to defend it when that freeze happens. Extremely sensitive varieties should only be tried if you live on the beach, or if you want to grow them in a container that can be moved inside on cold nights. Many tropicals can be grown to beautiful, fruitful trees in containers. But, how do you protect trees planted outdoors from the cold?

First, reserve the warmest spots for the most sensitive plants. Wooded areas if you have them, or close to your house on the south side are usually the warmest places. There are really only two ways to protect a plant from freezing.

First, you can try to conserve the heat stored in the ground by covering the plant. This buys time, delaying the drop to damaging temperatures until, you hope, the sun comes up and temperatures rise. Cloth covers work best. Don’t use plastic.

The second method is active protection—adding heat to the environment. Place a heat source, such as a light bulb, under the cover. Oil lamps, kerosene burners, candles, etc. are fine if you are mindful of the fire hazard.

Probably the best active protection is to keep a spray of water on the plant until freezing temperatures are past. Most tropicals will stand 32 degrees F, but many are damaged when the temperature drops lower. Water freezing on the plant forms a protective shield, keeping the temperature at 32 degrees F as long as water is supplied. Water releases a large amount of heat in the process of becoming ice. There is risk that the tree may suffer damage from the weight of accumulated ice, but the water, being much warmer than the air, helps to limit the thickness of ice. City water, rather than well water, will eliminate the risk of a power failure.

Trees that have survived three or four winters get large enough to have better resistance to cold damage. If your tree does suffer damage, be patient about cutting it back. Sometimes vigorous new growth will start from branches you thought were dead, and sometimes a tree you thought was gone will start to grow back from the ground. In the latter case, if the tree was grafted, it will need to be grafted again.

http://www.mrfc.org/articles/freeze.html

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Copper has been used for over 100 years as a fungicide in horticulture but what does it do to sensitive beneficial non target organisms like earthworms? The Good Soil project funded by the National Heritage Trust has found that the use of copper based fungicides can have detrimental effects on the earthworm populations of the north coast.

Copper is an essential element and required by all organisms, in fact deficiency results in reduction in biological function. However, elevated concentrations of copper are toxic and when found in soils may result in a range of effects including reduced biological activity and subsequent loss of fertility.

Why is copper such a problem?

Firstly, copper, being a metal, will naturally accumulate in soils binding to the clay and organic material. Secondly, the section of the soil where most biological activity occurs is also the place where most copper will accumulate when applied as fungicide, that is in the surface layers.  This is why it is of such concern for the biology of the soil.

What did the Good Soil Project do?

The project looked at earthworm numbers and earthworm avoidance in orchard soils contaminated by copper from fungicide use . Earthworms are often used, as indicator species’, to determine detrimental levels of a variety of chemicals in the environment as they are very sensitive to changes in the soil environment.  Worms are mobile and can move away from areas where excess copper (or any other chemicals) will harm them which shows, very clearly, where and when damaging chemicals are located.

As worms move away from areas high in copper the vital functions they perform are removed. Earthworms are vital in maintaining a health soil, through their feeding and burrowing activity. They aid in decomposition and incorporation of organic matter, increase the number of water soluble aggregates, improve water infiltration, aeration, drainage and root penetration, and increase microbial activity. Earthworm casts and burrow walls have higher concentrations of total and plant-available nutrients than surrounding soil and it has been recognised that surface feeding species distribute micro-organisms, spores, pollen and seeds both horizontally and vertically, Earthworms also reduce plant pathogens through digestion of fungal spores. By removing worms from orchards soils, this vital link in the soil biology is removed, and soil degradation will follow.

Orchards with high levels of copper in their soils surveyed in the project were found to have fewer worms in addition to other indicators of poor soil health. Mulch remained on the soil surface longer as there were fewer soil organisms to break it down and there appeared to be very little bioturbation ( mixing) between the soil and mulch above. In fact, earthworms were shown to avoid soil residues of copper between 25-50mg/kg, residue levels which can be attained by only 2 or 3 years of fungicide application.

How do you prevent this happening?

Once there is excess copper in the soil it is impossible to remove as it doesn’t break down. The best thing to do is prevent the accumulation in the first place. Using less copper based fungicides and/or using alternatives is a step in the right direction. If soils are high in copper, it may be possible to dilute the effect of the residue by applying organic material and maintaining the soil in a generally healthy state. This will reduce the bioavailability of the residues making them less toxic.NSW Agriculture, through sponsorship from the Rural Industries Research and Development Corporation (RIRDC) Organic Sub-Program, is currently conducting a review of alternatives to copper for disease control in the organics industry. Many of the findings of this review will be applicable to conventional horticultural production.

For more information:

Merrington, G., Rogers, S. L. and Van Zwieten, L. (2002) The potential impact of long-term copper fungicide usage on soil microbial biomass and microbial activity in an avocado orchard. Australian Journal of Soil Research 40(5) 749-759.

Abigail Jenkins,  Soil Advisory Officer NSW Agriculture  Ph:  02  6626 1357

abigail.jenkins@agric.nsw.gov.au