Aug 112018

Although it may look like there is not much happening with your fruit trees over winter, the microscopic world of fungi is making plans, strategically laying in wait in the cracks and crevices of your trees until the weather warms up. The most prevalent fungus is Peach Leaf Curl, causing the disfigurement of leaves, and sometimes the fruit, on your peach, nectarine, apricots and even almonds. However there are many other fungal problems that may occur and winter spraying is a good way to help reduce the incidence of fungal problems.

Peach Leaf Curl will cause the lovely new growth on your trees to appear blistered and puckered and in severe cases it can cause pimples on fruit and premature fruit drop. In the cool moist weather of early spring the fungus will multiply and if the cycle is not broken your trees will continue to be infested year after year.

Other fungal diseases that may be dormant on stone fruit include Shot Hole, Freckle Spot, Rust and Powdery Mildew.

There are several things you can do to minimise the spread of Peach Leaf Curl and other fungal diseases in the garden.

Practise good garden hygiene. Pick up fallen leaves from the ground and avoid putting them in your compost. Remove damaged or rotten fruit and keep the tree pruned to an open vase shape to increase air circulation.

Plant your tree into well prepared soil in the right position with plenty of sun and good air circulation. Keep up a regular fertilising and watering schedule.

Spray your trees during winter with a low impact fungicide. ‘Winter-washing’ helps to kill off any spores and can greatly reduce the incidence of Peach Leaf Curl and other fungal problems.

Winter Washing

The best spray to use is either copper oxychloride or lime sulphur sprayed in alternate years. The first spray should be in late autumn at leaf fall just before the tree enters its dormancy. Spray again at bud swell or bud burst in late winter or early spring. Once the leaves have opened out it is too late to spray for Peach Leaf Curl and many other fungal diseases. Safe and effective spraying can only be done at the end of the following summer.

When spraying fruit trees, be aware of the potential impact that ‘spray drift’ may have on surrounding vegetation, soil micro-organisms, pets and humans. Spraying is usually done to the point of ‘run-off’, where the spray liquid has completely covered the tree surface and runs off on to the ground. It may be prudent to lay spray sheets down so non-targeted areas are being protected.

Only make up enough spray for the job at hand to avoid the problem of having to dispose of excessive amounts of unused spray.

Spraying may not be 100% effective so be vigilant over summer and remove any leaves showing signs of fungal disease as soon as they appear.

  8 Responses to “Winter Washing of Fruit Trees”

  1. Copper can be a problem if used repeatedly. Lime sulphur is preferable. If you want to use up your copper oxchloride, use it in alternate years to lime sulphur. Of the inoculants you mention, worm castings would be more effective since they contain a diversity of microorganisms rather than one or a limited range as with the othes.

  2. I have heard that copper oxychloride will build up in your soil and continue to fumigate indiscriminantly all fungi in your soil. Therefore reducing the microbial biomass …. apparently copper doesn’t degrade/breakdown once in your soil profile. I am considering not using copper any more… and if i use the lime… I will follow up with gogo juice, lactobaccilus or worm castings and try and inoculate the soil. This will aid to greater health for the plants..

  3. No, it is a different chemical compound.

  4. We appreciate your concern about the lime sulphur and copper sprays. Lime has a very low impact on insects and other aspects of the environment and is rated highly in the SGA’s Garden Product Guide – Safe for You’n’ Nature which we are working on. Lime sulphur is approved by NASAA for use as a fungicide. Other recommended actions to reduce infection by the fungus is to keep the tree healthy and to keep leaves and other organic material away from the base of the tree so that moisture does not accumulate during colder months.

  5. That’s really interesting – if the smell is not a problem.

  6. If you have a worm farm, you can supplement their diet w/ boiled eggs. The wee that you tap off will stink, but it’ll be rich in sulphides – fantastic as an antifungal agent & more effective than anything you’ll buy over the counter.

  7. Unfortunately those sprays don’t seem very friendly to visiting good insects.
    Are there other ideas? Such as companion plantings?

  8. Is copper chelate the same?

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