Attractants for Adult Southern Corn Root worm (Coleoptera: Chrysomelidae) Monitoring in Peanut Fields and Relationship of Trap Catch to Pod Damage

Abstract

Field studies were conducted in 12 locations in southeastern Virginia to evaluate 3 trap attractants, 1,2,4-trimethoxybenzene, indole and trans-cinnamaldehyde (TIC), trans-cinnamaldehyde, alone, and sex pheromone (10-methyl-2-tridecanone), for monitoring adult southern corn root worm, Diabrotica undecimpunctata howardi Barber, phenology in peanut, Arachis hypogaea L.; and to determine the relationship of trap catch to peanut pod damage as it occurred throughout the season. Pheromone traps caught more beetles than TIC or cinnamaldehyde on most sample dates and at most locations. Pheromone traps detected 2 distinct beetle peaks, the 1st between 16 and 23 June, and the 2nd between 21 and 28 July, and consistently caught more males than females. TIC and cinnamaldehyde traps caught more females in 14 out of 180 observations (15 sample dates, 12 locations) and failed to detect the 2nd beetle peak. Peanut pod damage began to increase in all locations at the end of July. Total pod damage (immature plus mature pods) exceeded 40% in all but one location. Peak damage occurred at all but 1 location on ≈11 August. Peak pod damage by southern com root worm larvae consistently lagged behind the 2nd peak in the beetle population by 2.1 ±0.5 (±SEM) wk. Number of beetles trapped accounted for only 10% of the variance observed in peak pod damage. Use of pheromone traps by growers could allow for a more precise timing of insecticide applications and improve management of southern corn root worm in peanut.