Population Levels of Tarnished Plant Bugs (Heteroptera: Miridae) and Beneficial Arthropods Following Early-Season Treatments of Geranium dissectum for Control of Bollworms and Tobacco Budworms (Lepidoptera: Noctuidae)

Abstract

Wild geranium, Geranium dissectum L., was treated between late March and early April to control the F1 larval generation of the tobacco budworm, Heliothis virescens (F.), and bollworm, Helicoverpa zea (Boddie). Treatments were a single mowing, a single application of the herbicide (2,4-dichlorophenoxy) acetic acid (2,4-D), four applications of Heliothis nuclear-polyhedrosis virus (Elcar) formulated with Bacillus thuringiensis (Thuricide) and Gustol (a feeding stimulant), and an untreated check. Tarnished plant bugs, Lygus lineolaris (Palisot de Beauvois) and beneficial arthropods were sampled weekly during a 7-wk period to determine effects of the treatments on their numbers. The Elcar (virus) treatment had no significant effect on numbers of beneficial arthropods or L. lineolaris. Beneficial arthropod numbers were reduced by the mowing and 2,4-D treatments by an average 56.5 and 45.6% (as compared with those in the untreated check), respectively. Tarnished plant bug numbers were reduced by an average 40.5% for adults and 78.8% for nymphs by the mowing treatment, while reductions averaged 65.3% for adults and 72.9% for nymphs after the 2,4-D treatment. The effectiveness of mowing and 2,4-D treatment in reducing numbers of L. lineolaris , along with their previously reported effectiveness against F1 larvae of H. virescens and H. zea found in G. dissectum , make these treatments potentially valuable control options for the three pests during the early season before their movement into cotton.