Resistance of potato clones to Bemisia tabaci biotype B

Resistance of potato clones to Bemisia tabaci biotype B The resistance of 30 potato genotypes to B. tabaci (Genn.) biotype B (Hemiptera: Aleyrodidae) was evaluated in three greenhouse experiments. In the first experiment we evaluated the attractiveness, the preference for oviposition and the trichome density in a free-choice test in randomized blocks design with 30 treatments and three replications. In other experiment, no-choice preference for oviposition was evaluated (randomized blocks, nine treatments and five replications). The whitefly egg-adult cycle was monitored using a statistical design in randomized blocks with five replications. In the free-choice test, the genotypes NYL 235-4 and MAC 2 were the most attractive to adults, whereas HPC 5B and BAP 82 presented the lowest number of adults. The genotypes HPC 6R, BACH 4, clone APTA 2135, HPC 9B, BAP 82, 'Baraka' and HPC 5B presented the lowest number of eggs. Clone NYL 235-4 had the greatest number of simple (ST) and glandular (GT) trichomes, whereas clone CH 2 had the lowest number of ST, and HPC 5B, 'Radosa', 'Cupido', 'Caesar', 'Saginaw Gold', BACH 3 and HPC 1B of GT. There was significant correlation between adult attractiveness and oviposition preference. In the no-choice test, only the genotypes BACH 4, HPC 9B, 'Baraka and 'Achat' remained resistant. Consequently, for these four genotypes non-preference is the oviposition resistance mechanism. The egg adult cycle varied from 34.4 to 36.6 days. For the adult emergence, genotypes BAP 82, 'Baraka' and BACH 4 showed the lowest number of adults emerged, suggesting the presence of antibiosis. Genotypes BAP82, 'Baraka' and BACH 4 were resistant to B. tabaci biotype B.