Here we look at fruit trees and homemade pest remedies for common pests and diseases.
Both commercial and home made organic pest control for dealing with fruit tree pests and diseases can be effective if used correctly.
The best cure is prevention, and the most effective way of preventing pest or disease problems in your fruit trees is to keep them healthy.
Here are a few general tips for caring for fruit trees:
- Correct any soil mineral imbalances and condition your soil properly with adequate organic matter.
- Mulch your trees in spring or autumn (both for young trees) with nutritious materials such as seaweed, wool, straw and pea hay. Keep the area immediately around the trunk free of mulch or you’ll risk collar-rot.
- Feed your trees with a layer of compost put down before mulching, plus a scatter of poultry manure or blood and bone over the top of the mulch if they look like they need it.
If you feed too much of these high nitrogen fertilizers though, you will end up with leaf growth rather than fruit, and may actually encourage pests.
You could also provide adequate nitrogen by sowing a living mulch of clover around your tree in winter.
- Give infested trees a tonic of liquid manure made from nettles, compost, comfrey or seaweed used as a foliar spray or soil conditioner.
- Don’t prune your trees in winter as the open wound provides an entry point for diseases. It’s better to prune in summer and then only as necessary.
- Don’t cultivate the soil around your fruit trees. It disrupts the feeder root system and can shock your tree, making it more susceptible to pests and diseases.
Fruit Tree Companion Planting
Pesky insect pests often rely on smell to find their target plants.
Fruit tree companion planting with aromatic herbs can help confuse pests and reduce the number that find their way to your precious plant.
Try growing strong smelling herbs such as chives, henbit, Coriander, garlic, marigold, tansy and mustard under your trees.
NATURAL PEST CONTROL of APHIDS
Aphids are the bottom of the garden food chain, and so are the main fare for a wide variety of other critters. For natural pest control of aphids you have to allow them to build up for several weeks before thinking about active control, or you will starve their predators before they have had a chance to get established!
I tried this myself and found that the waiting game paid off with a veritable army of aphid predators rushing to the feast.
Aphid predators are many and include:
- Wasps and hover flies:
There are many species of wasp and hover fly like insects that adore eating aphids either as adults or larvae. Aphids parasitized by Chalcid wasp larvae will look dark and “mummified”. Hoverfly larvae look just like a little caterpillar.
Encourage those that feed exclusively on nectar as adults by letting parsley, carrot and fennel flower and growing native plants near your gardens. Buckwheat, Poached Egg Plant, Sunflower, Yarrow and Wild Angelica are good for attracting Hover Flies.
Both adult and larval Lady Bugs (or Lady Birds) exclusively eat aphids – up to 200 a day! The larvae look like a dark spotted grub.
Larvae of the graceful Lacewing are fearsome little critters that resemble a tiny Earwig in shape with a good set of jaws at the front.
- Predatory midges:
The adults are tiny, delicate flies that feed on nectar. Their young are small brown maggots that love eating aphids as well as mites, scale, white flies and thrips.
Predatory midges are commercially available and are often used effectively in greenhouses for year-round control.
FRUIT TREE APHIDS REMEDY
All Purpose Soap Spray
A good orchard spray that controls sucking mites, aphids, Rutherglen Bug and thrips but does not seem to affect spiders can be made as follows:
Just grate 2/3 of a cake of soap (save up those pesky little bits left over until you have enough) into 4.5 liters (1 gallon) of hot water. For a more effective recipe, add 1 tspn white oil, 300mls of old cooking oil and 2 tspns of caustic soda to the mix while it is still hot.
Use it once it has cooled to room temperature and only spray it on parts of the trees affected by pests. Avoid spraying anything onto plants during hot periods of the day.
To make larger quantities (enough for 100 trees) combine 18 gal (68 liters) of waste cooking oil (ask at your local fish and chip shop), 1 liter of white oil (optional), 9 gal (34 litres) of water, 3 kg (6.6 lbs) caustic soda and ½ box of washing machine soap powder in a large cooking pot and simmer gently for 3 hours.
Pour into containers to cool and solidify, then use as a spray at the rate of 2 kg soap to 20 liters of water.
When it comes to fruit tree diseases black leaves are really primarily a pest problem rather than a disease.
Black Sooty Mold is common in aphid-infested trees, especially citrus. This is because it grows on a honey mist produced by aphids higher up in the tree that drifts down onto the leaves below.
You’ll probably also find a lot of ants on your trees with these black leaves. They are there to “milk” the sweet sap from the aphids, and actively protect their little herds from predators like Lady Bugs and Lacewing larvae.
You can keep ants off the tree by greasing around the base of the trunk with a thick layer of Vaseline or a skirt of sump-oil soaked rag.
As for the aphids, just deal with as described above.
Fruit Tree Crinkle Leaf Disease
Leaf curl disease is caused by a fungus, and particularly attacks peaches, but will also affect almonds and apricots, resulting in a deformed, crinkled leaf.
This is a useful fungicide:
Suspend 90 g (3 oz) of copper sulfate in the toe of an old stocking overnight.
Blend with 100 g (3.3 oz) of slaked lime, and 4.5 liters (1.2 gallons) of water. Add a further 4.5 liters of water and use immediately. It is useful for leaf curl, especially at the bud stage in the first year to conserve the scarce early leaves.
Also good on vege crops against potato and tomato blights, black spot on beans.
Do not use every year as excess copper will tie up other soil minerals, and copper toxicity can also result.
With Fruit Fly in fruit trees and homemade pest control ideas it’s hard to give you a sure-fire solution.
If you happen to live outside of a Fruit Fly area you are blessed. They are a real problem for us folks who don’t!
The main fruit fly pests in Australia are Queensland fruit fly, native to rainforest areas of Australia’s north-east coast, and Mediterranean fruit fly found only in Western Australia.
Want to know how to get rid of Fruit Flies? Forget it! The best you can hope for is to minimize the damage they do to your fruit, and this requires a combination of different strategies:
The life cycle of a Fruit Fly is similar to that of the ordinary house fly and can be complete from eggs to adult in just 4 weeks. The mated female fly lays eggs in your fruit, and after the maggot has wrought its destruction, it drops to the ground, spending a short period as a pupa in the soil under the tree before hatching out again as an adult.
Chooks (as well as Guinea Fowl) will happily scratch around and feast on the pupae and newly hatched adults (it takes a day for their wings to harden enough for flight) so incorporate a chicken run amongst susceptible fruit trees during the fruiting season.
DESTROY AFFECTED FRUIT
When the adult female Fruit Fly pierces the skin of the fruit and lays her eggs, the wound either weeps or leaves a dimple.
You can arrest the life cycle by removing affected fruit from the tree and sealing them into a black rubbish bin bag and leaving them in the sun for a few weeks before composting them or feeding them to your livestock.
AVOID PLANTING SUSCEPTIBLE VARIETIES
I once lived in a house that had a beautiful old apricot tree in the garden. But we never got to taste a single apricot, as all were ruined by Fruit Fly! Then I moved to where there were several varieties of plum, not one of which was affected. Fruit Fly rely on being able to pierce the skin of the fruit to infect it, so fruit with soft skin is more susceptible than that with tougher skin.
The most susceptible fruit varieties are figs, apples, pears, loquats, guavas, feijoas, cherries, stone fruit (especially apricots, peaches and nectarines) and even vegetables such as tomatoes and capsicum.
Fruit Fly resistant varieties include avocado (except thin-skinned Fuerte and Rincon), banana, blueberry, citrus, grapes, kiwifruit, lychee, mulberry, nashi pear, passionfruit, paw paw, pomegranate and tamarillo.
FRUIT FLY BARRIERS
An effective Fruit Fly barrier must have a weave of less than 2 mm. Suitable materials are mosquito netting, gauzy curtain fabric, shade cloth and fly screen mesh.
You can drape it over the whole tree with it during fruiting (if you are planning on this approach either pick dwarf varieties or keep your tree pruned short) supported by a frame made of poly pipe arches. However, it will also screen out some of the sunlight.
Alternatively, you can make (or buy) special sleeves sized to tie around bunches of fruit on the tree. Commercial Fruit Fly exclusion bags are made of cloth or waxed paper. You should put them on as soon as fruit starts to form, and could combine the job with fruit thinning at the same time.
Fruit Fly barriers have the added advantage that they also exclude other pests such as birds and possums.
FRUIT FLY TRAPS
Bad news for controlling Fruit Fly in fruit trees and homemade pest solutions… Homemade Fruit Fly traps only generally trap the male flies, and are only effective while they are fresh. Nearly all the insects they trap are not even Fruit Fly. Their only practical use is as a monitoring tool to see how many Fruit Flies are around.
You can make a homemade Fruit Fly trap by hanging a plastic bottle in your tree with a small (1cm) entrance hole drilled near the top. You can bait it with a “tea” containing vegemite, urine or vanilla essence. Painting a bit of color around the entrance hole will attract more flies – yellow for the Mediterranean Fruit Fly and blue for the Queensland Fruit Fly.
Commercial baits are also available but again, as their action is based on pheromones, only attract the male flies. They are a feasible long-term way to reduce the population only if you live in an isolated area with few other sources of either fruit or Fruit Fly around.
Organic splash baits like Naturalure are good too. They are sprayed either on the foliage or onto a piece of plywood suspended in the tree early in the fruiting season and must be applied weekly (and after rain) to work well.
They are effective on both male and female flies and work by luring them with a specific protein feed attractant that is laced with a natural insecticide that kills the fly once ingested. Beneficial insects are not harmed.
Codling Moth can be a problem for apple growers in Australia that appears in spring and gets worse by Christmas as the population builds up.
The best approach is multi-faceted:
In spring (late October) put out some traps to check for the presence of male Codling Moths.
CODLING MOTH TRAP
Dissolve 1 part sugar and 1 part molasses into a jar of water and cover with a 3/16 inch mesh (this will effectively trap the moths but not bees). Check daily.
If you see a few males then treat susceptible trees as follows:
CODLING MOTH TREE TREATMENT
Selectively spray the little clusters of blossom on your trees with a Pyrethrum based spray.
CODLING MOTH COCOON TRAPS
Band the trunk and larger branches of your apple trees by tying on 6 inch wide strips of cardboard (the type with a corrugated layer) in November, late December and February. These will provide attractive sites for the Codling Moth caterpillars to make their cocoons. Just check them for larvae and kill those you find.