Distribution of Bemisia tabaci (Hemiptera: Aleyrodidae) biotypes in Italy

Esterase banding patterns in native polyacrylamide gel electrophoresis, squash silver leaf (SSL) induction, and tomato yellow leaf curl begomovirus-Sardinia (TYLCVSar) transmission capability were investigated to evaluate variations among populations of Bemisia tabaci (Gennadius) from Italy and to relate their distribution to their geographic origin. Adults of the B biotype, adults of the Q-like biotype (which is similar to a Spanish biotype), and adults without esterase bands were found. The B biotype has been found in Italy since 1989. Two populations, including mainly B and Q-like biotypes, showed similar TYLCV-Sar transmission efficiency, independent of esterase banding pattern. Only populations from Liguria and Sardinia, which contained almost exclusively B-biotype individuals, were able to induce SSL. We observed that adults of the B biotype are widespread in greenhouses of northern Italy and Sardinia, whereas those of the Q-like biotype are present only in fields of southern Italy. These results suggest that the B biotype of B. tabaci was introduced into Italy likely while trading ornamental plants, whereas the Q-like biotype is native to the Mediterranean region.