Effects of sustained-release methoprene and a combined formulation of liquid methoprene and Bacillus thuringiensis israelensis on insects in salt marshes
Sp. Lawler et al., Effects of sustained-release methoprene and a combined formulation of liquid methoprene and Bacillus thuringiensis israelensis on insects in salt marshes, ARCH ENV C, 39(2), 2000, pp. 177-182
Citations number
27
Categorie Soggetti
Environment/Ecology,"Pharmacology & Toxicology
Journal title
ARCHIVES OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY
Aquatic insects are an important component of the food web in salt marshes,
therefore it is necessary to test whether pesticides used to control mosqu
itoes in salt marshes are safe for nontarget insects. We tested the nontarg
et effects of a combined formulation (duplex) of Bacillus thuringiensis isr
aelensis (B.t.i.) and liquid methoprene (an insect development regulator) o
r sustained-release methoprene pellets (Altosid(R) pellets) by applying the
se materials to replicated salt marsh ponds at maximum label rates. Untreat
ed ponds served as controls. We measured effects of the pesticides by reari
ng immature mosquitoes (Aedes dorsalis) and water boatmen (Trichocorixa ret
iculata) in predator-exclusion cages and by monitoring uncaged populations
of invertebrates using replicated sweep-net samples. Both pesticides killed
caged mosquitoes, and the activity of the Altosid(R) pellets continued thr
ough 99 days. There were no detectable effects of either pesticide on the s
urvival or maturation of T. reticulata, or on abundances of uncaged inverte
brates. The long-term activity of the pellets could help minimize mosquito
abatement activity in salt marshes where there are breeding birds or endang
ered species. However, other studies suggest that this advantage needs to b
e balanced against the risks that sustained-release formulations could lead
to development of resistance in mosquitoes or that initially undetected no
ntarget effects could build over time.