Author
 |
Snodgrass, Gordon |
|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings Publication Acceptance Date: 1/1/2003 Publication Date: 7/1/2003 Citation: Snodgrass, G.L. 2003. Reproductive diapause in tarnished plant bugs and its effect on non-insecticidal control measures. In: Proceedings Beltwide Cotton Conference, January 7-9, Nashville, TN. 2003 CDROM. http.www.cotton.org/beltwide Interpretive Summary: The tarnished plant bug is a serious pest of cotton grown in the midsouth. It is controlled in cotton exclusively with insecticides, and because of its resistance to several classes of insecticides, it has become increasingly more costly and difficult to control. Control measures not based on insecticides are needed. The development of non-insecticidal control measures requires a thorough knowledge of the basic biology of the pest. A big part of plant bug biology which has had little research is reproductive diapause. This physiological state allows adults to overwinter. The current research found that in the field nymphs start producing diapausing adults near the end of August. By 12 September, 50% of nymphs in the field will produce adults in diapause. Diapause is broken during December and mating occurs, by January in winters with average or above temperatures nymphs are present on winter hosts. New generation adults are produced by mid-March. In cold winters, new generation adults are not produced until mid-April. This information is useful in development of non-insecticidal control measures such as release of sterile adults, population suppression by treatment of early season wild hosts, and release of biological control agents. Technical 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 possible non-insecticidal control methods are discussed. |
