SAMPLING OF THE COTTON APHID (HOMOPTERA, APHIDIDAE) IN COTTON

Seven sampling experiments. involving the cotton aphid, Aphis gossypii Glover, were conducted during the 1990 through 1992 growing seasons. Results demonstrated that the highest portion of the population was fo und consistently in the lowest portion of the plant canopy regardless of aphid density. We suggest the following sampling scheme for determi ning numbers of cotton aphids during the cotton growing season: 1) fir st three weeks after planting (plant emergence to fourth true leaf) - use whole plant washes; 2) fourth through sixth week after planting (f ourth leaf to pinhead square) - sample the fourth fully expanded leaf from the terminal; 3) seventh through ninth week after planting (pinhe ad square to first-bloom) - sample the first main stem green leaf abou t one-third the distance from the terminal; and 4) remainder of the se ason (first bloom to end of season) - sample the first main stem green leaf above the first basal fruiting branch.