ABSTRACT

Reproductive diapause in the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), was studied by dissection of field collected adults or adults reared from field collected nymphs in 1999-2001 near Stoneville in Washington County, MS. The critical photoperiod for diapause induction was about 12.5:11.5 (L:D) h, or 12 September. Overwintering adults collected from winter host plants in December 1999 and 2001 began breaking diapause in the second and third weeks of December at a day length near 10:14( L:D) h. Most of the overwintering females collected on winter host plants had mature eggs by the end of December in both winters. In the winters of 1998-1999 and 1999-2000, tarnished plant bug nymphs were found in January and produced an early new generation of adults by the second or third weeks of March. In these mild winters, host plants were not killed or stunted by cold weather. In the cold winter of 2000-2001, nymphs were not found until March with new generation adults produced in April. The effects of diapause on control of tarnished plant bugs by non-insecticidal methods which could be developed are discussed.