Submitted to: Agricultural and Forest Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/2/2002
Publication Date: 5/1/2003
Citation: HAMMACK,L. ., VOLATILE SEMIOCHEMICAL IMPACT ON TRAPPING AND DISTRIBUTION IN MAIZE OF NORTHERN AND WESTERN CORN ROOTWORM BEETLES (COLEOPTERA: CHRYSOMELIDAE), AGRICULTURAL AND FOREST ENTOMOLOGY, 2003, (5) Vol 2: 113-122. Interpretive Summary: Plant attractants were tested as tools to move Diabrotica corn rootworm beetles into field areas to be treated with toxic baits for population suppression via mass removal of reproductive adults. When dispensed from sticky traps in maize, 2-phenyl-1-ethylamine and 2-phenyl-1-ethanol caught more northern corn rootworm beetles than did 4-methoxyphenethanol. The amine was attractive before and after maize flowered but not during intervening silk or blister stages. Amine responsiveness recurred by early milk stage before 50% emergence of adult female northern (and western) corn rootworm was observed and before populations declined for the season. Although synergy of the amine with 2-phenyl-1-ethanol did not arise until maize was late milk stage, this amine-alcohol blend doubled the density of northern but not western corn rootworm beetles when applied (0.37 point sources per square yard)in milk-stage or younger maize plots. No-lure traps sin attractant-treated plots captured more female, but not male, northern corn rootworm than did traps in untreated control plots, hinting that females caused most of the detected increase in beetle density. The results suggest that lures can concentrate females within field areas before most egg laying occurs and can thus complement a variety of corn rootworm control strategies aimed at reducing pesticide use.
Technical Abstract: Tests assessed lures as tools to move corn rootworm beetles to small field plots for removal. Plots bore 36 dispensers (0.44/sq. m) each releasing about 1.5 and 0.8 mg/day of 2-phenyl-1-ethylamine and 2- phenyl-1-ethanol, respectively. The blend lured mostly northern corn rootworm, Diabrotica barberi (NCR), but data were also obtained for western corn rootworm (WCR), Diabrotica virgifera virgifera. Tests to lure beetles into maize plots were done in late vegetative and milk stages, when the blend proved attractive, unlike 4-methoxyphenethanol. However, amine-alcohol synergy in attracting NCR females was not evident until maize matured beyond early milk stage. Beetle counts at 2, 24 and 48 h post treatment on maize plants located midway between lure sources indicated that treated plots contained at least twice as many NCR beetles as did matched control plots. Captures on no-lure sticky traps placed in lure treated plots hinted that the increase was due mostly to females. No-lure, medicine-vial traps yielded low captures that did not vary with treatment. No significant effects on WCR densities or trap captures occurred. Fewer than 50% of NCR (and WCR) females had emerged from the soil by milk-stage onset, when female response to the binary blend recurred after its loss during maize silking. The data suggest that lures can concentrate females within field areas before most egg laying occurs and can thus complement a variety of corn rootworm control tactics, including area-wide use of cucurbitacin-based adulticides.