A statewide survey was conducted in tobacco fields throughout 17 counties in North Carolina to determine distribution and relative abundances of red and green color forms of the tobacco aphid, Myzus nicotianae Black man. Samples of tobacco aphids from infested fields were collected during the survey and used to establish 36 laboratory cultures. A carboxylesterase assay was performed on aphids from each established laboratory culture to determine general carboxylesterase hydrolyzing activities. Significant differences among cultures were observed. Activities ranged from 40.04 μM 1-naphthol produced per minute per red aphid in Wayne County to 77.36 in Bladen County. Activities in green aphids ranged from 17.12 in Johnston County to 53.52 in Watauga County. Aphids with high carboxylesterase activities (>40 IJ-MI-naphthol produced per minute per aphid) were of both colors; however, all aphids with low activities <22) were green. When a squash technique was used to identify the karyotype of aphids from the cultures, two karyotypes were identified in the aphids. These were 12 chromosomes with a normal configuration and 12 chromosomes with a I, 3 autosomal trans location. All red aphids possessed the trans location. Aphids from four of the nine green cultures had the trans location. All four green forms with the trans location had high carboxylesterase activities (>40 μM I-naphthol produced per minute per aphid). The five cultures with normal karyotypes had low activities <22).
No takes yet. Share an insight, caveat, or question.
Harlow et al. (1991) studied this question.