Pest infestations and plant diseases
Doesn't take long to realise you REALLY need to know about pest control. Spring has started and I have "peach leaf curl" and "mealy cabbage aphids" attacking my crops. Oh, and those pretty white butterflies that indicate Spring is in the air....well...they are really Satan in disguise! I am learning by google-ing! What to do about it, in an organic, environmentally safe way? Well, I just want to drown the little buggers in chemical heavy pesticides and herbicides and save my crop. But, no. There has to be an organically sound and responsible answer.
Preventing "Peach Leaf Curl"
Read this article:
http://www.weeklytimesnow.com.au/article/2012/07/25/513071_print_friendly_article.html
Summary:
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Once leaf-curl has attacked, even in the earliest stages, it is a waste of time spraying.
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This job has to be done before leaf buds start to break open, which is why late winter is the best time to apply controlling sprays such as lime sulphur or copper-based fungicides, such as Bordeaux or Burgundy mixtures.
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The blossom buds of peach and nectarine trees begin to swell and turn pink around the second week in August or a little later according to variety and locality.
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This blossom swelling always happens before the leaves emerge, so indicate a perfect time to spray.
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Ideally, trees should be sprayed to the tips of branches twice, first at the end of July and again about August 10-15 at the pink-bud stage.
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The sprays protectively coat leaf buds and surrounding bark with fungus killer.
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It suppresses the leaf-curl fungus, preventing it from infecting the opening leaves. Keep in mind that if spraying is delayed until after leaf buds begin to open, it is already too late and the leaves will be infected.
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But once the initial protection has succeeded and disease-free leaves start to unfurl, they have become resistant to infection. It is only at that brief opening-bud stage while the still-compressed leaves are moist and sticky that the disease is able to gain entry.
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This is why the correct timing of anti-leaf-curl spraying is so crucial.
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The same sprays can also be used on other stonefruits, such as apricots and plums - always before leaf-burst - to help control brown rot disease, shot hole, mildew of grapevines and in the ornamental garden to counter black spot of roses.
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Bordeaux and Burgundy sprays are particularly effective if mixed and used while still fresh.
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To make it, dissolve 100g of white builders lime in five litres of water and, in a separate plastic container, dissolve 100g copper sulphate in another five litres of water.
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The lime mix is gently poured into the copper to obtain Bordeaux.
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It must be agitated while spraying to avoid blocking spray heads.
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For the much stronger, non-blocking Burgundy mix, replace the lime with washing soda.
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These mixtures retain strength for a couple of weeks.
Mealy Cabbage Aphids
Mealy Aphid is a pest predominantly of brassica such as cabbage cauliflower and turnip, as well as Kale. My main weapon is insecticidal soap: basically just fatty acids, you spray them all over the plants and they coat the aphids, cutting off their air supply. Netting brassicas is also a method as they are self pollinating, so do not depend on insects to pollinate. It will make your garden look unnatural, but it will keep the pests out.
More Biological controls:
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Invite Ladybirds, Lacewing, Aphidius wasps and Hover flies to your garden by planting .....Queen Anne's Lace; Fennel; Tansy; Dandelion
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Add some praying mantis (stick insects) to your garden
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add Cryptolaemus bettles or Leptomastix wasps
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plant basil, catmint, coriander, fennel, garlic, lavender,garlic chives, marigolds, mint, narturtiums, onion, pyrenthrum, rosemary, sage. nearby
Organic Chemical Control:
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Basil Spray Recipe - 1L boiling water over 2 packed cupfuls of chopped basil leaves. Cover and leave to stand until liquid is cold. Strain and use within a few days.
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pyrethrum spray - grow pyrethrum in a pot in the garden. Pick the flowers and dry them as quickly as possible. Coarsely grind the dried flower heads and to every firmly packed hald-cup of flowers, add iL of boiling water. Shake well before use. The spray kills bees so only spray in the early morning or evening when bees aren't around.
Cabbage White (moth) Butterfly
Plants favoured by cabbage moth and cabbage white butterfly include cabbage, broccoli, Brussel sprouts, Chinese cabbage, celery, beetroot, rocket and watercress.
How to control these pests: (Click on link)
Cultural control
Intercropping checker board style with plants which are not members of the cruciferious family but have similar height will increase the chance that a cabbage moth (and cabbage root fly?) will fail to get the required two in a row cruciferious touch downs. This failure means the moth will not lay an egg at that time (Row, Peter 2011, the science of gardening)
White Powdery Mildew
What is Powdery Mildew?
Powdery mildew refers to a group of diseases that all show up as a powdery white coating on leaves, stems and sometimes even flowers. It does not usually kill plants, but it can weaken them and diminish photosynthesis, leading to poor yield and plants that don't last the season.
It is spread by spores that are carried by the wind or splashed onto leaves. Powdery mildew favors humid, rather than wet conditions. The spores form when the humidity is high and disperse when the humidity diminishes. Spores can over-winter on plants or plant debris and start the process all over again. Garden sanitation and planting disease resistant varieties are your pest powdery mildew controls.
There are several species of powdery mildew fungus and they each have their preferred hosts. Powdery mildew on zinnias will not move to lilacs or cucumbers.
Once Your Plants are Infected:
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Remove and destroy all infected plant parts
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Improve air circulation by thinning and pruning
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Don't fertilized until the problem is corrected. Powdery mildew favors young, succulent growth
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Don't water plants from above
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Apply a fungicide: There are many fungicides available. Check the label to be sure they are safe and effective on the type of plant that is infected. Look for ingredients such as: potassium bicarbonate, neem oil, sulfur or copper. There are also chemical fungicides, such as triforine, that can be used on ornamental plants. There is also a home remedy made from baking soda that is effective.
1 tablespoon baking soda
3.5 litres water
1/2 teaspoon liquid soap
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Most fungicides will need repeat applications every 7 - 14 days, for continuous protection. Always follow the label instructions for both application and waiting period before harvest
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Milk solution:
The dilution used by home gardeners is 1 part milk to 2 - 3 parts water. The solution is then sprayed on the plant's leaves every 10-14 days. It works best as a preventative, rather than a cure, which makes it hard to determine whether it actually works since you don't know if your plants would have gotten it anyway.
As to exactly how milk works against the fungus, no one is certain. It appears that the proteins in milk offer an antiseptic-like effect, when exposed to sunlight. To be effective, the solution should be applied in bright sun. Soak both sides of the leaves until the solution is dripping.
