ABSTRACT

Life history parameters of the cotton aphid, Aphis gossypii Glover were investigated under field conditions in Lubbock, Texas. Newly emerged aphid nymphs (n=30) were reared singly in aphid cages on the fifth mainstem node leaf in cotton and followed through all life stages until the last individual from the cohort died. Instar-specific nymphal duration consisted of 37, 42, 35, and 33 degree-days (>5.8 ºC developmental threshold) for first, second, third, and fourth instars, respectively. Cotton aphid mortality began at 432 degree-days and the last aphid died at 924 degree-days. Aphid reproduction began at 142 degree-days and the daily fecundity peaked at 266 degree-days; reproduction ceased at 773 degree-days. The cotton aphids produced an average of 63 offspring in the 30-day reproductive lifespan for the cohort. The gross reproductive rate, net reproductive rate, and finite rate of increase were 62.24, 59.06, and 1.4326, respectively.