Copper sprays can be effective if applied during dormancy
Distorted and blistered leaves are signs of peach leaf curl.
Now is the time to spray peach and nectarine trees to control
it. (Photo courtesy UC Statewide Integrated Pest Management)
It may be Thanksgiving, but it’s time to talk peaches. In particular, this conversation is about peach leaf curl.
This common fungal disease only attacks peach and nectarine trees. It distorts and puckers foliage and new shoots. It can completely defoliate a tree, leaving any developing fruit to sunburn or shrivel. Over time, it greatly cuts down on a tree’s productivity.
And it comes back, year after year after year. Once it’s established, peach leaf curl will be an issue every spring.
The time to combat this fungus is not when you see its damage in April or May; it’s now, in the days before and after Thanksgiving.
To control leaf curl, peach and nectarine trees benefit from dormant spraying with a copper fungicide or copper soap. Horticultural oil helps make that copper spray stick to the twigs and branches.
According to the UC Integrated Pest Management Program, the copper spray smothers the fungal spores that overwinter on the tree.
“The fungal spores that cause the disease spend the winter on twigs and buds and germinate in the spring,” say the IPM experts. “For effective control, treat trees just after leaves have fallen, usually late November or December.
"A second application in late winter before buds swell can be considered, especially in areas with high rainfall or during wet winters. Don’t apply fungicides during the growing season because they won’t be effective.”
A dry, calm and fogless almost-winter day; that’s the perfect time to spray. And that’s also the forecast for the greater Sacramento area this Thanksgiving weekend and early next week. Copper sprays need 24 hours of dry, calm weather before and after application. This is a good window of spraying opportunity.
If needed, prune before spraying. Pick up any dropped foliage and discard (don’t compost). Those fallen leaves may carry leaf curl, too.
For more on treating peach leaf curl: http://ipm.ucanr.edu/QT/peachleafcurlcard.html
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For week of Dec. 10:
Take advantage of these dry but crisp conditions. It’s time to get out the rake!
* Rake leaves away from storm drains and keep gutters clear.
* Fallen leaves can be used for mulch and compost. Chop up large leaves with a couple of passes with a lawn mower.
* Prune non-flowering trees and shrubs while they’re dormant. Without their foliage, trees are easier to prune.
* Rake and remove dead leaves and stems from dormant perennials.
* Make sure to take frost precautions with new transplants and sensitive plants. Mulch, water and cover tender plants in the late afternoon to retain warmth.
* Succulent plants are at particular risk if temperatures drop below freezing. Don’t water succulents before frost; cover instead. Use cloth sheets, not plastic. Make sure to remove coverings during the day.
* Clean and sharpen garden tools before storing for the winter.
* Brighten the holidays with winter bloomers such as poinsettias, amaryllis, calendulas, Iceland poppies, pansies and primroses.
* Keep poinsettias in a sunny, warm location. Water thoroughly. After the holidays, feed your plants monthly so they'll bloom again next December.
* Just because it rained doesn't mean every plant got watered. Give a drink to plants that the rain didn't reach, such as under eaves or under evergreen trees. Also, well-watered plants hold up better to frost than thirsty plants.
* Plant garlic (December's the last chance -- the ground is getting cold!) and onions for harvest in summer.
* Bare-root season begins. Plant bare-root berries, kiwifruit, grapes, artichokes, horseradish and rhubarb. Beware of soggy soil. It can rot bare-root plants.
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