Studies on overwintering hosts of Bemisia tabaci biotype B in Spain
Glasshouse studies have been carried out in Spain to evaluate adult preference, distribution, fecundity and mortality of Bemisia tabaci biotype B (B. argentifolii - EPPO A2 quarantine pest) on several winter-spring crop hosts: potato, faba bean, cabbage and lettuce (leaf and cos types). The authors pointed out that in addition to protected crops, ornamental crops and weeds, several vegetables grown in winter-spring could serve as potential overwintering reservoirs for B. tabaci biotype B in countries having mild winters. Adults of B. tabaci biotype B have been released into a glasshouse containing cabbage, faba bean, lettuce and potato. Numbers of adults and eggs per plant, distribution of the pest within the plants and mortality were recorded. The results indicated that the number of eggs laid per adult was highest on potato, cabbage and faba bean. Within the plants, the adults were most often found on the newest leaves of cabbage and faba bean, and were more evenly distributed on potato. On both types of lettuce, adults were usually on older leaves. Survival from egg to adult emergence was much higher for potato (81.8 %), faba bean (73.1 %) and cabbage (59.6 %) but than for the two types of lettuce (13.5 % for cos and 3.9 % for leaf lettuce). The authors concluded that that potato, cabbage and faba bean can be significant winter-spring hosts of B. tabaci biotype B in many areas with mild winters. Lettuce did not appear to be a preferred host or to allow good reproduction of the pest. Note: the EPPO Secretariat had previously no information on the possible presence of the B biotype of B. tabaci in Spain.
Sources
Zalom, F.G.; Castañé, C.; Gabarra, R. (1995) Selection of some winter-spring vegetable crop hosts by Bemisia argentifolii (Homoptera: Aleyrodidae).
Journal of Economic Entomology, 88(1), 70-76.