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It's time to take another trip to the home orchard. Hopefully, you've picked the last apples and it is time to do a few last tasks.
It's OK to take your pruning tools but limit your cuts to dead, diseased and broken branches. (Heavy pruning should be done in the spring.) Once the leaves fall, it's easy to see problem areas, and taking care of them now is easier than waiting until spring. Removing dead or diseased wood also reduces hiding spots for insects.
Be sure to dispose of cuttings -- either by shredding, composting or throwing them out with the trash. If you want to use larger limbs as firewood, stack them away from the orchard and burn the wood as soon as it is dry.
Turn your attention to your peaches, nectarines and other stone- fruit trees. The concern here is a fungal disease called coryneum blight -- also known as shot-hole blight. It can infect the leaves, fruit, buds, blossoms and twigs. It causes considerable damage and is much more serious when the fall weather is moist.
The disease gets the name from infections that appear as small tan spots on young leaves. The spots turn brown with purple borders, and they eventually drop out of the leaf. The leaves appear as if they are perforated with bb's or shot -- hence the name.
In Utah, peach and nectarine leaf infections are the most common, but they can occur on plums, cherries and apricots if the weather is very wet.
This disease has the ability to infect through the bud scale scar, the small area that is left open when the leaf falls from the tree. The fungus grows, infecting the buds and twigs, forming cankers that grow and surround leaf or flower buds.
These purple or brown cankers are slightly sunken. They enlarge and grow together to girdle a branch or twig and kill it. The infected buds and cankers then produce copious amounts of gum. This leaves your tree with numerous small dead twigs.
In addition, the fungal spores can be moved -- by rain -- to leaf or flower buds and remain until spring, when spores infect and kill the buds. This causes blossom blight, which then spreads to the leaves, where it causes the shot-hole symptoms in the leaves. While the twig infections commonly damage peaches, fruit infections are less common.
The fungus overwinters. This means you have to act now to prevent more damage. Apply protective fungicide sprays -- Bordeaux, chlorothalonil (Daconil) or fixed coppers -- in wet years right after the leaves fall.
Use spreader-stickers or dormant oil with the fixed coppers to keep them on the tree. Then protect young leaves and fruit (especially apricots) with protective sprays during the spring.
