Fourth International Bemisia Workshop International Whitefly Genomics Workshop
The Biotypes B and Q of Bemisia tabaci in Israel – Distribution, Resistance to Insecticides and Implications for Pest Management
1 Dept. of Entomology, ARO, Gilat Research Center, Israel. Correspondence: hrami@volcani.agri.gov.il
2 Dept. of Entomology, ARO, The Volcani Center, Bet Dagan, Israel
Two biotypes of the whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), have been documented from Israel. Biotype B was recognized in the early 1990s and biotype Q was first evidenced in 2000. In order to determine the biotype status of B. tabaci in Israel, various whitefly populations collected during 2000–2006 from field and greenhouse sites were examined with DNA markers. The markers were developed through cleaved amplified polymorphic regions (CAPS) analysis, based on primers complementary to the mitochondrial cytochrome oxidase I (mtCOI) gene sequences. The whitefly collections were part of a nationwide program to monitor resistance to several important whitefly control agents such as, pyriproxyfen, acetamiprid and diafenthiuron. Based on the collected samples, both the B and Q biotypes are present throughout Israel, and field populations may consist of a mixture of the two biotypes. Their distribution probably depends on crop type, climate, and the intensity of treatments with pesticides. Restrictions to interbreeding between the two biotypes of B. tabaci were found, and it may resolve differences in biochemical and physiological characters and symbiont composition of these biotypes. A link between B. tabaci biotypes and insecticide resistance was found under field and laboratory conditions. In various locations the Q biotype has reached moderate to high resistance levels to pyriproxyfen (Resistance ratio= 25 – 600-fold). No resistance to pyriproxyfen was detected in the B biotype. Accordingly, B biotype predominates on organic farms, while numerous insecticide applications have selected for Q biotype elsewhere.