ABSTRACT

The pest status of Lygus on the Texas High Plains is becoming more important. An increase in Bt cotton acreage, several mild winters and some new insecticide technologies are some of the factors that may contribute to increased densities during the cotton production season. The two species of Lygus of economic concern on the Texas High Plains are Lygus hesperus Knight and Lygus elisus Van Duzee (Armstrong, unpublished data). Field and laboratory experiments were conducted to compare the feeding injury and damage potential of L. hesperus with L. elisus to one-third grown cotton squares during the 2001 and 2002 cotton seasons. In the field studies, first position cotton squares from the 6, 9 and 11th nodes were enclosed with both species for 24 hrs. Each infested square was observed for abscission and followed to seed-cotton yield. Laboratory experiments involved enclosing Lygus species on the same position squares as the field-study but conducting it in the laboratory where the anthers were dissected after 24 hr. A rating system was developed to determine the effects of the digestive enzymes on the developing anthers. Results from field and laboratory studies indicate that L. elisus can cause similar or greater damage to cotton anthers compared to L. hesperus. Cotton will compensate from feeding injury from both species, masking yield losses from square abscission. Both species have a very similar damage potential as a pest of Texas High Plains cotton.