HONEYDEW PRODUCTION BY KNACK- OR APPLAUD-TREATED SWEETPOTATO WHITEFLY (SPW) NYMPHS FEEDING ON NUCOTN 33 B AND DP 5415 COTTONS, 2002

Abstract

Sticky cotton lint caused by Sweetpotato whitefly (SPW) honeydew contamination can interfere with cotton lint processing at the textile mill. As a result, honeydew contaminated cotton lint may be price discounted or rejected in the market place. Knack and Applaud are insect growth regulators that sterilize eggs and interfere with eclosion from the last nymphal instar or inhibit chitin synthesis. Our previous reports showed no measurable effects on honeydew production for SPW adults or nymphs collected from Knack or Applaud treated field plots. However, in the laboratory, first and second instar nymphs feeding on cotton leaves dipped in solutions of Knack and Applaud produced less honeydew sugars the nymphs feeding on leaves dipped in water solutions. In this study we compared honeydew production of SPW nymphs and their mortality after mist applications of Applaud to nymphs or after Applaud or Knack leaf dip application to eggs, in all cases, on NuCOTN 33 B (Bt) and DP 5415 cottons. Mists or leaf dips of water alone were served as checks.