Editor’s note: Kelly R. Jackson takes questions over the phone at the Christian County Extension Office and answers them in the Garden Corner column.
Question. My apple tree is loaded with fruit. Should I thin out some of the apples?
Answer. It is possible to have too much of a good thing. In the case of apples, excessive fruit can interfere with fruit bud development this summer resulting in little to no crop next year. This can become an annual cycle, called alternate bearing, if thinning is not done.
Thinning ensures a good crop of fruit every year. Other benefits to thinning are that the remaining fruit will grow larger and there will be less branch damage caused by the weight of excessive fruit.
Thin apples so that remaining fruit are 4 to 6 inches apart. Thinning is also beneficial to peaches, which should be spaced 6 to 8 inches apart; pears and plums are spaced 4 to 6 inches apart; cherries do not need to be thinned.
Q. I’ve been finding shallow holes in my lawn that look like something has been digging. Any thoughts on what it could be?
A. Everything from dogs to moles to crayfish can make holes in the lawn. Recently, I’ve been seeing shallow holes in the ground, surrounded by a ring of loosened soil. These holes tend to appear overnight. Holes like this are typically associated with skunks. Skunks dig at nighttime in search of earthworms, grubs, and other soil insects.
The hole is about the size of their nose, which presses into the soil as it digs with its front claws. As the claws form a loose ring of soil around part of the hole. If a lot of feeding takes place, the soil can become very disturbed as if it has been tilled. This is a seasonal problem associated with periods of heavy rain. As soon as the soil dries, earthworms and grubs will move deeper into the soil. Without easy access to food, skunks will move on.
Q. What causes the bumps on my maple/oak leaves?
A. This time of year we start seeing growths that appear on trees’ leaves, maple and oak especially. The growths or bumps are called insect galls and are often caused by interactions between plant hormones and growth-regulating chemicals produced by some species of wasps, flies or mites.
Galls provide their inhabitants with needed nutrients, proper environment and protection. An example is the wool sower gall, caused by a small wasp. It appears on white oak in early summer and resembles clusters of toasted marshmallows. The gall is comprised of a group of smaller, hairy, seed-like structures, each containing a developing wasp.
Usually, there are only a few scattered galls on trees. Weather, predators, parasites and diseases usually combine to keep gall numbers at low to moderate levels. Most galls have little if any effect on healthy trees. Insecticide sprays of foliage or use of systemic products usually do more harm to natural enemies than to gall makers, so treatments are not recommended. Cultural practices that reduce stress and promote general growth and health allow trees to tolerate galls and other arthropods that develop on trees. Pruning stem and twig galls when populations are low may provide some control.
Kelly R. Jackson is the Christian County Extension Agent for horticulture. He can be reached at 270-886-6328 or visit Christian County Horticulture online at www.christiancountyextension.com.