GardenLine | Common Saskatchewan Pests | Tarnished Plant Bug

Bonnie Willie

This species of plant bug can be responsible for the misshapen apples, strawberries, and even raspberries that you may have noticed in your yard or orchard.

DAMAGE

Both the nymphs (immatures) and the adults extract plant juices by sucking on stem tips, buds and fruit. As they feed they inject a toxin that deforms roots, blackens shoot tips, dwarfs and ruins fruit and spoils flowers. Leaves will even take on a speckled appearance and if the infestation is large enough, premature leaf drop will also occur.

DESCRIPTION AND LIFE CYCLE

The adult tarnished plant bug is greenish-yellow to brown, with yellow, brown and black markings. They are flat, "beetle-like" insects about 1/4 of an inch in length and have a distinctive yellow triangle at each end of the forewing. They fly when disturbed.

The adults overwinter in leaf debris or other protected areas. In early spring the adults become active and deposit eggs in stems, leaf parts and flowers of host plants. The eggs hatch within a week to 10 days. The nymphs that emerge are yellow-to-green in colour. They molt 5 times, appearing more like the adult with each molt. Nymphs reach the adult stage in about 30 days. There may be 3 to 5 generations per year depending on location and latitude.

CONTROL

Good garden sanitation is the primary method of plant bug control. This involves cleaning up all plant debris in the fall and elimination of weeds and if possible, legumes.

Insecticides, if warranted, should be used when flower buds begin to break and then repeated when 90% of the petals have dropped. Timing is critical in order to avoid harming pollinating insects. Chemicals such as Cygon, Sevin, malathion and pyrethrins may be used according to label instructions.

REFERENCES:

Tree and Shrub Insects of the Prairie Provinces;W.G.H. Ives and H.R. Wong; Information Report NOR-X-292. Northern Forestry Centre, 1988.

Rodale's Garden Insect, Disease and Weed Identification Guide; Miranda Smith and Anna Carr, 1988.

Insect Pests of Farm, Garden and Orchard; 7th Ed. Ralph H. Davidson and William F. Lyon, 1979.

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Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.