Short communication. Mechanisms in competition, under laboratory conditions, between Spanish biotypes B and Q of Bemisia tabaci (Gennadius)

Laboratory studies were carried out on aspects affecting competition between biotypes B and Q of whitefly [Bemisia tabaci (Gennadius)]: mating behaviour, egg viability and pyriproxyfen resistance. Pairs of biotype B females and males spent more time as courting couples than pairs with Q males, regardless of female biotype. Mixed pairs of biotype Q females and biotype B males spent more time as courting couples than biotype Q pairs. Egg viability from the different crosses and from single females was similar. Pyriproxyfen application to a mixture of whiteflies with a biotype ratio B/Q of one gave a reduction in the ratio because of higher resistance of the Q biotype to the insecticide. The data agrees with the observed displacement of biotype Q by biotype B whiteflies under laboratory conditions, and vice versa in the field.