Problem type: Insect
Name of problem: Ash Plant Bug
Plant name(s): Ash
Symptoms / Characteristics:
Feeding causes foliage to appear mottled or speckled, creating yellow blotches, which later turn brown. Severe symptoms include leaf disfigurement, premature defoliation and reduced vigour. Black varnish-like faecal pellets can be seen on leaf undersides.
The ash plant bug, Tropidosteptes amoenus feeds by puncturing leaf surfaces with its piercing sucking mouthpart. There are two generations of the ash plant bug per year. The eggs overwinter underneath tree bark and the nymphs emerge in the spring. The first generation of adults occurs in midsummer, followed by a second generation in late summer. The second generation of adults will survive on the tree until frost. Adult ash plant bugs can range in color from green to black. They are about 5 mm long and 2 mm wide. Pink markings are frequently seen on live bugs.
Control / Preventions:
Severe infestations warrant the use of chemical insecticides in order to eliminate adults before they lay eggs. Spray between mid May and early June to control the first generation adults and again between mid July and early August to control the second generation of adults that lay the overwintering eggs. Commonly used insecticides include carbaryl and dimethoate. Insecticides must be applied according to manufacturer instruction.
Relevant web sites:
Johnson, W.T. and Lyon, H.H. 1988. Insects that Feed on Trees and Shrubs. Second Edition. Comstock Publishing Associates, Cornell University, Ithaca, NY. 556 pages.