Studies on sampling for Bemisia tabaci on Cucumis melo in Arizona
Studies on spatial distribution of Bemisia tabaci (EPPO A2 quarantine pest) have been carried out in Arizona (US), in three fields of cantaloupe (Cucumis melo) grown in spring. Weekly sampling began when adult whiteflies were detected on sticky traps (April) and was carried over a period of 6-7 weeks. Each week, eggs, first to mid-fourth instars, late fourth instars (red-eyed nymphs) and adults were counted on leaves from terminal and crown portions of the plant. At sampling date, adults were counted at two different hours of the day (07.00 and 13.00) on entire leaves and immature stages were counted once on leaf portions. The results showed that adults were more abundant at 07.00 on terminal leaves, but red-eyed nymphs were more abundant on crown leaves. There were no significant density differences between leaf sections within leaf positions for any immature life stage. Eggs were also more abundant on terminal leaves. It was also observed that all life stages had an aggregated spatial distribution. The authors felt that during early season, it is preferable to sample adults early in the morning on terminal leaves of C. melo. These results could be useful when establishing sampling plans for the management of B. tabaci populations on C. melo.
Tonhasca, A.JR., Palumbo, J.C.; Byrne, D.N. (1994) Distribution patterns of Bemisia tabaci (Homoptera: Aleyrodidae) in Cantaloupe fields in Arizona.
Environmental Entomology, 23 (4), 949-954.