Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/6/2005
Publication Date: 6/1/2005
Citation: Snodgrass, G.L., Villavaso, E.J. 2005. Occurence of tarnished plant bug populations with two intensities of diapause in the mississippi river delta. National Cotton Council Beltwide Cotton Conference. Interpretive Summary: Tarnished plant bugs are serious pests of cotton in the mid-South where they are controlled in cotton exclusively with insecticides. Because of resistance or tolerance to insecticides used in their control, they are becoming more difficult to control. Alternative control meausres not based solely on insecticides are needed. The development of alternative control measures requires a thorough knowledge of plant bug biology. A critical part of plant bug biology is diapause, since diapause allows plant bugs to overwinter as adults. In the present study, plant bugs were found to overwinter in the mid-South in two intensities of diapause. In one part of the overwintering population, adults were active on winter host plants all winter and broke diapause during December. This allowed these adults to produce new generation adults by mid-March in warm winters. A second part of the population was found in plant debris and these adults were in a more intense diapause which was broken during January. These plant bugs would be more likely to survive cold winters in which winter host plants were killed or stunted, since they would have to survive a shorter period of time after diapause was broken before wild host plants for food and reproduction became available. The tarnished plant bug is well adapted to its winter habitat for survival in cold winters and for the production of an early new generation in warm winters.
Technical Abstract: Overwintering tarnished plant bugs adults, Lygus lineolaris (Palisot de Beauvois), were collected near Stoneville, MS, from henbit, Lamium amplexicaule L., or plant debris during December 2003 and January 2004 and dissected to determine their reproductive status. Diapause in adults collected from henbit was broken during December, and most males and females were reproductive by the end of December. Adults collected from plant debris were in a more intense diapause which was broken during January, and most adults were reproductive by the end of January. Previous research showed that in winters when henbit bloomed in December through March new generation adults were produced on henbit by mid-March. In the current stdy, a cold period from mid-January through mid-February stunted henbit and new generation adults were not produced on henbit until April. This new generation produced in April resulted from adults that overwintered in plant debris along with any surviving adults that overwintered on henbit. These adults utilized henbit that began to regrow and bloom in late-February along with other hosts that bloomed in March and April. Our results again showed that the tarnished plant has an overwintering population with two intensities of daipause. This enabled the tarnished plant bug to produce new generation adults in March and April in warm winters in the mid-South. In winteres with cold periods that kill or stunt winter hosts, the part of the population that breaks diapause in January is better able to survive and produce new generation adults in April. The tarnished plant bug is well adapted to its winter habitat in the mid-South.