Honeylocust plant bug and leafhopper
The honeylocust plant bug and the honeylocust leafhopper are small, green insects commonly found on the foliage of honeylocust trees during late spring. Both species are tiny, active, light green nymphs when first encountered in mid-spring. They are elongate-oval and pointed at both ends. They run rapidly about on the foliage and stems and are frequently first noticed because of the nuisance they create by falling out of the trees and crawling on people passing below. If you collect a branch sample for later inspection, you will get to observe this annoying behavior as they run about your car, office and body.
There is only one generation of leafhopper and plant bug on honeylocust each year. The eggs overwinter in woody tissues and begin to hatch in late April. The nymphs feed for several weeks and begin to transform to adults by early or mid June. When the adults emerge, the feeding damage is over for the year and no new symptoms develop. New leaflets that emerge after the insects cease feeding will be normal and new foliage eventually conceals the early-season symptoms. Otherwise healthy trees will look completely normal by mid-summer.
The amount of damage to honeylocust foliage varies greatly from year to year, from place to place and even from tree to tree. Much of this variation appears to be related to weather during early spring and to the development of the tree leaves prior to the emergence of the insects. If leaves are already on the tree, the foliage will become stippled, speckled, twisted and stunted at the ends of the branches. If the attack began before the tree leafed out, the foliage will fail to emerge.
Controls for honeylocust plant bug and leafhopper are generally not recommended. Trees are not permanently damaged and there is no long term threat to health and vigor. The damage is temporary and more annoying than serious. If control is warranted such as on very young, newly-transplanted or highly-stressed trees, spraying with a contact insecticide at the time the insects are first noticed will provide adequate control in most situations.