(Des Moines) Japanese beetles are causing damage to fruiting trees and other plants across Southwest Iowa this summer.
The invasive beetles feed between the veins of leaves, leaving them with a lace-like or skeletonized appearance. Some of their preferred plants include roses, grapes, apple and cherry trees, raspberries, hollyhocks and corn silks.
Japanese beetles begin as grubs in grassy soil before emerging in late June or early July. The adult beetles feed on plants throughout July and August.
Healthy, mature trees can typically tolerate a significant amount of damage, but young or stressed plants may suffer serious injury or die. He said the beetles ate the corn silks off of Lorenzen’s sweet corn. They are also attracted to grapes, raspberries, cherry trees, and apple trees.
Residents can remove the beetles by shaking plants early in the morning or evening, when the insects are less active, and dropping them into a bucket of soapy water. Netting can also be placed over plants, but it should not be used while they are flowering and need pollination.
Japanese beetle traps are not recommended because they may attract more beetles to a yard than they catch. Garden insecticides may also be used when damage becomes severe.
