Laboratory evaluation of lufenuron on immature stages of potato tuber moth(Lepidoptera : Gelechiidae)

The effects of the chitin synthesis inhibitor lufenuron against potato tube r moth, Phthorimaea operculella (Zeller), eggs were determined by topically exposing different age groups of eggs (1-4 d old) to treated potato tubers (Solanum tuberosum L.) under laboratory conditions. Larval hatch from both treated (4 and 12 g [AI]/100 liter) and untreated tubers was >95%, but mor tality of first instars was high in treated tubers (>90%) compared with unt reated tubers. Examination of the treated tubers showed that most of the la rvae were unable to penetrate or cause any noticeable damage to the potato tubers. However, the few first instars that survived were able to penetrate the tubers and continue their development to the pupal or adult stages. At 12 g (AI)/100 liter, adult emergence was <2% and most of the emerged adult s had morphological deformities such as reduced wing size and they were una ble to free themselves front the pupal sacs. These data suggest that topica l application of lufenuron to eggs before larval hatch would reduce the amo unt of damage caused by potato tuber moth as part of integrated pest manage ment program.