Fermented or Floral? Developing a Generalized Food Bait Lure to Monitor Cutworm and Armyworm Moths (Lepidoptera: Noctuidae) in Field Crops

SIMPLE SUMMARY: Cutworms and armyworms are part of a group of moth pests that cause occasional damage to field crops on the Canadian Prairies. There are no reliable tools for monitoring the moth population before larval damage occurs. Food bait volatiles attract male and female moths and could be used to monitor several pests with a single lure in a single trap. We focused on enhancing a food bait lure of acetic acid and isoamyl alcohol to monitor the redbacked cutworm and other moths in canola and wheat fields. Trapping experiments tested food bait at different release rates, from different dispensers and in combination with various chemicals. High-release lures captured more females in canola, while low-release lures captured more males in wheat. Therefore, the crop where traps are positioned affects the moth trap catch. Food bait combined in an inert matrix caught more moths than bottles or plastic bag dispensers did. More females were attracted to food bait lures with isobutanol than to those with floral volatile. Fermented volatiles appear to be a more reliable attractant than floral volatiles for these moths. Depending on the sex, the feeding status affected the strength of the antenna response to the different volatiles. Females had a higher response to isobutanol if the moth was previously fed a sugar solution. Food bait lures should be further developed to monitor redbacked cutworm moths and other pests in field crops. ABSTRACT: Cutworms and armyworms (Lepidoptera: Noctuidae) are a pest complex in North America that cause sporadic damage in field crops on the Canadian Prairies; however, no methods have been developed to reliably monitor population densities. Food-based semiochemicals attract both sexes of adult moths and could be used to monitor multiple species with a single lure in a single trap. Here, we focus on enhancing the attractiveness of acetic acid and 3-methyl-1-butanol (AAMB) lures to redbacked cutworm (Euxoa ochrogaster) (RBC) and other noctuid pests. Experiments conducted in canola and wheat fields tested AAMB lures at different release rates, from different devices and in combination with other semiochemicals. High-release lures captured more females in canola, while low-release lures captured more males in wheat. Thus, crop volatiles may influence response to lures. Semiochemicals embedded in an inert matrix caught more RBC moths than semiochemicals released from Nalgene or polyethylene dispensers did. More RBC females were attracted to AAMB lures with 2-methyl-1-propanol than phenylacetaldehyde. Fermented volatiles appear to be a more reliable attractant than floral volatiles for these species. RBC moth antennae produced significant responses to all doses of phenylacetaldehyde tested in electroantennogram assays, but only to higher doses of acetic acid and 3-methyl-1-butanol. Physiological state of the RBC moths also influenced responsiveness to the tested semiochemical. Feeding status did not influence the antennal response to acetic acid and phenylacetaldehyde in either sex, but it increased the response to 3-methyl-1-butanol in females when fed. AAMB lures should be further developed to monitor RBC moths and other noctuid pests in field crops.