The Permacultivator - Journal of Cool Climate Permaculture
As the seasons change from the seemingly dormant winter into the sudden flush of spring it’s easy to get carried away with the thoughts of crops to come. Orchard yields can, however, be severely effected by activities (or lack of) undertaken from winter through to summer. Whilst we might want to hibernate during the short, cold days, the diligent orchardist will have been busy pruning, tidying and cleaning as part of their integrated pest management (IPM) regime.
Pruning is vital for managing the size and shape of trees so that fruit can be reached for thinning and harvesting and also allow netting from marauding birds, bats and possums. Pruning also plays an important role in preventing and managing pests and diseases. MOST importantly ALL pruning tools need to be sharp to ensure clean cuts that are less vulnerable to fungal diseases. Clean and disinfect tools in a bleach solution before pruning each tree, especially where there are diseased trees. All mummified fruit, dead, diseased and infested growth should be pruned off and removed from the orchard. This material is best burnt or otherwise put through a mulcher, well composted and the compost used well away from the orchard. Remove crossing and inwardly growing branches to open the canopy allowing sufficient air flow and light penetration to make conditions less favourable for fungal diseases. Consider using the clean prunings in a creative way such as weaving into retaining walls, compost bays or other structures rather than just taking them to the tip.
Many pests have overwintering strategies to ensure their survival through the cold months. To prevent pests such as codling moths and fruit fly, sources of overwintering populations need to be found and removed. Inspect any stored fruit for signs of infestation and either feed to fruit eating animals or drown in water for 10 days. Infested fruit that has fallen or thinned during the growing season should be treated in the same way. Inspect the trunks, and branches of apples for codling moth cocoons and scrub off and squash any found. Cracks in wood on ladders, in sheds, storage boxes and on the alternate hosts of codling moth such as; pears, quince, hawthorn, japonica, crab apple, walnut and stone fruits also offer overwintering sites. Include these areas in your hunt and the potential for infestation will be greatly reduced. Fruit fly overwinter in long-hanging fruit such as citrus and loquats. If stung fruit are found remove all the fruit and dispose of infested fruit and peel accordingly. Fruit fly require soil contact for their lifecycle therefore making composting or burying unsuitable practices. An alternative to drowning is to seal the fruit in air tight garbage bags until rotted down. Compost piles are havens for fruit fly so either place vegetable and fruit scraps well into the pile where it will get hot, consider a closed bin system, or feed scraps to animals.
Fungal diseases such as curly leaf, powdery mildew and black spot can cause crop losses if allowed to proliferate. Bordeaux spray (copper sulphate and hydrated lime) is a common low toxicity fungicide, however, it can cause severe leaf damage if used incorrectly. It is an effective treatment for peach curly leaf if sprayed at leaf fall and then again just before bud burst. As with all chemicals ensure adequate safety precautions are taken. Regular monitoring of the orchard will allow you to identify fungal outbreaks early. Remove diseased fruit and leaves and dispose of well away from the orchard. Regular use of preventative sprays such as seaweed, chamomile, casuarina, and horsetail teas can help to prevent outbreaks. Watering at ground level and keeping grass low will also aid in preventing fungal attack.
As I write buds are swelling so it’s too late for pruning now but there’s still time to clean up around trees and implement preventative strategies. Whilst you’re cleaning, thinning and harvesting keep in mind the pruning job you’ll have to do next winter!
J47 Spring 2005 -Summer 2006