Vegetable Crops News
Insecticides and Spined Soldier Bug
In many IPM programs it is often necessary to supplement biological control with
insecticides. Even insecticides touted as being less harmful to natural enemies should be
carefully evaluated before being incorporated into an IPM program.
Diafenthiuron is a miticide considered harmless to the whitefly parasite Encarsia formosa
and the minute pirate bug. Although it was practically non-toxic to spined soldier bug when
applied topically, severe mortality occured when bugs ingested it by drinking contaminated
water or were exposed to dry residues. It was also more toxic to adults than nymphs, probably
because the adults eat and move around more than nymphs, increasing the potential for exposure
and risk of poisoning.
Imidacloprid, a newly developed insecticide with activity against a wide variety of
sucking insects, caused significant mortality in nymphs and adults through all routes of exposure.
However, soil rather than foliar applications may adequately limit spined soldier bug exposure
and allow its use in IPM programs.
De Cock, A., P. De Clercq, L. Tirry, and D. Degheele. 1996. Toxicity of diafenthiuron and imidacloprid to
the predatory bug Podisus maculiventris (Heteroptera: Pentatomidae). Environ. Entomol. 25: 476-480.
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