CRYPTIC INVASION OF THE EXOTIC BEMISIA TABACI BIOTYPE Q OCCURRED WIDESPREAD IN SHANDONG PROVINCE OF CHINA

Bemisia tabaci (Gennadius) is an important agricultural pest worldwide. The pest is a species complex composed of numerous biotypes, among which biotypes B and Q are the 2 most invasive and widely distributed. Our previous study found that the ratio of the biotype Q has been increasing and displacement of biotypes B by Q has been occurring on cotton and eggplant in Shandong Province of China during the past several years. To determine whether biotype Q has been increasing on other hosts and possible displacement of biotypes has been occurring in the province as a whole, we further surveyed B. tabaci biotypes B and Q on cultivated and wild host species near cotton or eggplant fields in 7 locations of Shandong Province during 2005-2008 with cleavage amplified polymorphic sequence (CAPS) of the mtCOI (mitochondrial cytochrome oxidase subunit I) marker. This research showed biotype Q has been increasing on all kinds of host plants and the displacement of biotypes B by Q has been occurring in the province as a whole. The displacement mechanism should be further researched and such knowledge might guide the application of the insecticides or adjustment of the crops to effectively control the pest.