Author
|
Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/3/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Insecticide resistance significantly reduces the ability to control German cockroach populations. Detection of insecticide resistance before treatments are chosen and dispensed would improve control and eliminate inappropriate insecticide applications. A scientist at the Center for Medical, Agricultural and Veterinary Entomology, Gainesville, Florida has developed a bioassay method capable of detecting pyrethroid (cyhalothrin) insecticide resistant German cockroaches. In addition, a relationship between mortality at a fixed dose of insecticide and resistance was identified. Whether this simple relationship can be used to estimate the magnitude of resistance in the field requires further investigation. Technical Abstract: -Cyhalothrin resistance levels of 13 recently-collected field strains of German cockroach, Blattella germanica (L.), were determined by topical insecticide bioassay. The resistance levels (LD50 field strain/LD50 of the susceptible Orlando strain) ranged from 3- to 71-fold. Residual bioassays were conducted simultaneously against the Orlando insecticide susceptible strain, the HRDC strain (carbamate resistant), the Village Green strain (pyrethroid resistant), and the Marietta strain (pyrethroid, carbamate, and organophosphorus resistant) to determine a diagnostic dose for use in resistance detection bioassays. The LC99 of the Orlando susceptible strain (0.9 æg/jar) and 5 times the Orlando LC99 (4.5 æg/jar) were chosen for use in -cyhalothrin resistance detection bioassays. A highly significant relationship was observed between mortality at 5 times the LC99 of Orlando (4.5 æg/jar) and resistance ratio (LD50 in topical bioassays). The relevance of this relationship to -cyhalothrin resistance detection is discussed. |
