Linear alcohol ethoxylates: insecticidal and synergistic effects on German cockroaches (Blattodea: Blattellidae) and other insects.
Sixteen linear ethoxylated alcohol surfactants (AEOs) were studied to determine their contact insecticidal activity to adult German cockroaches, Blattella germanica (L.) (Blattodea: Blattellidae). Within groups of AEOs of equal carbon chain length, insecticidal activity, measured as LT50 values (in minutes) and 24-h mortality after treatment, was inversely related to the amount of ethoxylation. There was a highly significant negative relationship between the hydrophile-lipophile balance (HLB) value of the AEO and contact toxicity. The AEO with the lowest HLB value, Tomadol 23-1 (HLB = 3.7), produced the greatest 24-h cockroach mortality. The contact activity of Tomadol 23-1 was evaluated against a wide range of other insect species. Most species were killed within 24 h by direct exposure (1-4 microl of a 50% ethanol solution) to Tomadol 23-1 or by spray exposure to an aqueous solution. Tomadol 23-1, at a sublethal concentration, was tested in combination with representative members of the carbamate, nicotinoid, organophosphate, pyrethrum, pyrethroid, and pyrrole insecticide classes. Significant synergism was demonstrated in combinations of Tomadol 23-1 and chlorfenapyr, clothianidin, imidacloprid, thiamethoxam, and pyrethrum. Tomadol 23-1 significantly reduced the insecticidal activity of propoxur, suggesting antagonism. The insecticidal activity of Tomadol 23-1 was synergized by coapplication with a sublethal amount of piperonyl butoxide, indicating the involvement of cytochrome P450 microsomal monooxygenases in insect metabolism of AEO surfactants.
Sims
Steven R
SR
Whitmire Micro-Gen, 3568 Tree Court Industrial Blvd, St. Louis, MO 63122-6682, USA. steve.sims@wmmg.com
Appel
Arthur G
AG
D000438:Alcohols / Q000737:chemistry; D000818:Animals; D020048:Blattellidae; D007300:Insect Control; D007313:Insecta; D007306:Insecticides / Q000737:chemistry; D008297:Male; D010574:Pesticide Synergists / Q000737:chemistry; D013329:Structure-Activity Relationship
D000438:Alcohols; D007306:Insecticides; D010574:Pesticide Synergists