Insecticide Penetration and Symptomology Studies on Larvae of Diabrotica undecimpunctata howardi (Barber)

✍ Scribed by Michaelides, Paris K.; Wright, Denis J.

• Book ID: 101216378
• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 258 KB
• Volume: 49
• Category: Article
• ISSN: 1526-498X
• DOI: 10.1002/(sici)1096-9063(199704)49:4<353::aid-ps539>3.0.co;2-8

✦ Synopsis

The internal and external levels of topically applied soil insecticides, teÑuthrin, terbufos and dieldrin, to 3rd-instar larvae of the southern corn rootworm, Diabrotica undecimpunctata howardi (Barber), were monitored over 48 h. Symptomology of poisoning with 10 times the dose of the larval 72-h for LD 90 each chemical was observed over 48 h at various time points after treatment. Terbufos penetrated more rapidly than teÑuthrin or dieldrin, although internal levels of teÑuthrin and dieldrin had a longer-lasting plateau than terbufos. A 72-h treatment with teÑuthrin resulted in faster penetration and also faster dis-LD 30 appearance from the insect compared with the 10 ] 72-h dose over a 48-h LD 90 period. Recorded symptoms of poisoning included regurgitation of gut contents, defaecation and writhing and these are suggested to play an important part in voiding of the toxicants at lower (sub-lethal) treatment levels. The sub-lethal e †ects of teÑuthrin are discussed with respect to likely pest behavioural changes, such as anorectic response, after Ðeld treatment of a crop.