Temperature Relationships in Organophosphorus Poisoning in Boll Weevils12
1970; Oxford University Press; Volume: 63; Issue: 2 Linguagem: Inglês
10.1093/jee/63.2.502
ISSN1938-291X
Autores Tópico(s)Insect Pest Control Strategies
ResumoA laboratory culture or organophosphorus-susceptible boll weevils was exposed at different temperatures to cotton leaves or filter-paper discs previously treated with insecticide or defoliant. All materials examined showed a positive temperature coefficient of toxicity with methyl parathion and malathion being the most toxic at all temperatures. The toxicities of azinphosmethyl and EPN® (O-ethyl O-p-nitrophenyl phenylphosphonothioate) were severely decreased at 10°C while DEF® (S, S, S-tributyl phosphorotrithioate) showed appreciable toxicity only at 32°C. Studies involving different exposure and holding temperatures indicated that a higher exposure temperature results in increased toxicity, even though the holding temperature is the same for all treatments. Although transferring the insects to a low holding temperature from a high exposure temperature decreased the effectiveness of the toxicant, the corrected mortality of the insects exposed at 32°C and held at 10°C was more than twice that of those exposed and held at 10°C. These data suggest that temperature may affect both the innate toxicity and the rate of absorption of the insecticide into the insect.
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