Silverleaf whitefly B. tabaci biotype B is an important worldwide pest of many crops. Use of resistant cultivars is considered the ideal method of control. In this research, 32 cultivars of melon were evaluated under greenhouse conditions reganding resistance to silverleaf whitefly. As to adult attractiveness, 'Neve' had the lowest number of adults on the abaxial surfaces of leaves (0.6 adult/10cm²) while 'Nilo' was the more attractive (5.6 adults/10cm²). The oviposition preference was evaluated in free-choice and no-choice tests. In both, 'Neve' was less oviposited and 'Nilo' had the highest number of eggs. The silverleaf whitefly colonization was evaluated by scores varying from 0 (no colonization) to 6 (leaves completely colonized). While 'Neve' showed the lowest level of colonization, high levels were observed in 'Imperial', 'Jangada', 'Vereda', 'Deneb' and 'Nilo'. The B. tabaci biotype B egg-adult cycle varied from 24.0 ('Neve') to 25.4 days ('Jangada'), without any significant differences among the genotypes. The lowest rates of adult emergence were observed in 'Vereda' (68.2%) and 'Nilo' (69.3%), suggesting that antibiosis is the mechanism of resistance, while 'Imperial' (90.9%) and 'Deneb' (89.6%) presented the highest rates. Considering the evaluated characteristics, 'Neve' is the most resistant cultivar to silverleaf whitefly and should be tested in highly infested areas. Additionally, it might be a valuable source of resistance for breeding programs.
Insecta; silverleaf whitefly; nonpreference; host plant resistance; Cucumis melo
