Probing and feeding behavior of two distinct biotypes of Bemisia tabaci (Homoptera : Aleyrodidae) on tomato plants

The probing and feeding behavior of 2 biotypes (B and Q) of the sweetpotato whitefly, Bemisia tabaci (Gennadius), were monitored using the electrical penetration graph (EPG) technique on tomato, Lycopersicon esculentum (Mill) ('Riofuego'). Seven EPG waveform patterns were distinguished. B. tabaci (B biotype) showed a shorter duration of potential drop pattern (4.73 +/- 0.4 5 s [ mean +/- SE], n = 125), longer time to reach the phloem (209 +/- 23.4 2 min, n = 22),and more complex pathway patterns than the greenhouse whitef ly, Trialeurodes vaporariorum (Westwood). Some differences were observed in feeding behavior of the 2 B, tabaci biotypes (B and Q) tested. Interesting ly, significant differences (P < 0.05) were found in those parameters relat ed with phloem events: total duration of the E(pd),E(pd)1,and E(pd)2 (P<0.0 1), as well as mean duration of E(pd) and E(pd)B. In addition, there also w ere significant differences in the total number of probes (P < 0.05). The Q biotype showed fewer number of probes and a longer phloem ingestion time ( pattern E(pd)B) than those from the B biotype. Hence, our results revealed a clear difference in the probing and feeding behavior between the B and th e Q biotypes of B. tabaci on tomato plants.