Bald Cypress Pests

Pest Identification

• Bald cypress is prone to infestation from the cypress leaf beetle. The pests most frequently are seen on the trees during June and July. Other common pests include the cypress twig gall midge and fall webworm. The cypress twig gall midge can reinfest a tree repeatedly if not controlled. Other host trees of the cypress twig gall midge include pond cypress and Montezuma cypress.

Description

• The cypress leaf beetle is very small in size, measuring less than ¼ inch long. This light yellow pest has distinct black markings on its body. The cypress twig gall midge is a 3-cm-long, clear-winged fly that lays clusters of translucent, orange eggs. The emerging larvae and pupa also are orange. The fall webworm is a white moth with yellow or greenish larvae. The maggots or larvae have black heads and black spots on their bodies.

Damage

• The adult cypress leaf beetles are foliage eaters and damage leaves as they infest tree crown. Symptoms of damage appear in the form of red discoloration of leaves and 3-mm-long gouges. The beetle larvae infest and feed on grass and weed roots. Cypress twig gall midge damage is characterized by the appearance of heavy spongelike, green growth on new leaves where the pests lays eggs. Excessive presence of galls causes branches to start drooping. The galls turn brown by fall and drop with the foliage, the larvae overwintering within the gall in the soil. Fall webworms damage trees by weaving foliage and small twigs together with their silk, and feeding on leaves within these little tents. The presence of webs and tents reduces the aesthetic quality of trees and leads to defoliation.

Control

• Using insecticides to control a cypress leaf beetle infestation is not recommended as the trees recover the damaged foliage during the same season. A larvicide applied to soil around the tree helps to control larva damage to grass. One of the best options for controlling the cypress twig gall midge is to rake and destroy all leaves from under the tree. Use pesticides to control adult flies. Control fall webworms by removing their nests manually. Avoid using insecticides unless there is an excessive population of pests in the tree. Use insecticides on small-sized larvae for best efficacy as it is hard to control insects once they retreat in their tents.