ABSTRACT

A single herbicide (Strike 3™) application in early season was made to marginal areas around fields, roads, and ditches in 23 square kilometer (9 square miles) areas of the Mississippi Delta in 1999, 2000, and 2001. The herbicide was used to kill broad leaf weeds in the marginal areas which served as food and reproductive hosts for tarnished plant bugs. The herbicide was effective and caused a significant reduction in wild host densities in the treated areas in all three years. Tarnished plant bug populations in treated areas did not increase significantly in the treated marginal areas during April and May following treatment of the areas in the first two weeks of March in 2000 and 2001. Significant increases in plant bug populations occurred on wild hosts in marginal areas in untreated areas in both years. The herbicide application was made in the first two weeks of April 1999, and in this year plant bug populations increased in marginal areas which were treated. The increase was caused by plant bugs moving to Italian ryegrass which was not affected by the herbicide. Ryegrass is abundant in marginal areas in the delta, and blooms during April. These results showed that the herbicide application was effective in reducing numbers of broad leaf wild hosts and plant bug populations that utilized them. To be most effective, the application should be made in late-February through the first two weeks of March to avoid moving plant bugs onto Italian ryegrass when it is in bloom and can serve as a host.