How long is miller moth season

However, army cutworms also occur in western Colorado and may be an important crop pests in late winter and spring. Adults similarly migrate to the mountains to spend the summer but less frequently occur as serious nuisance pests along the West Slope.

The army cutworm has an unusual life history. Eggs are laid by the moths in late summer and early fall. Most eggs are laid in weedy areas of wheat fields, alfalfa fields, or other areas where vegetation is thick—including turfgrass. Eggs hatch within a few weeks and the young caterpillars begin to feed. Army cutworm has a wide range of plants on which it feeds.

It prefers broadleaf plants but will also feed on grasses. Army cutworms spend the winter as a partially grown caterpillar, feeding as temperatures allow. In early spring the cutworms may damage crops, particularly alfalfa and winter wheat. They may also damage garden plants and are common in lawns. Army cutworms become full grown by mid-spring, burrow into the soil, and pupate. Pupation can occur as early as March or may extend into early May, depending on temperatures.

Next, they migrate and ultimately settle at higher elevations where they spend a few months, feeding on nectar and resting in sheltered areas. During this time they are in reproductive diapause , a physiological state during which they do not produce nor lay eggs. In early fall or late summer, they return to lower elevations, come out of diapause, and begin to lay eggs, repeating the annual, single generation life cycle.

Miller moths are the migrating adult stage of the army cutworm. In eastern Colorado, spring flights move westward, originating from moths that developed across eastern Colorado and border areas of Wyoming, Nebraska, Kansas, and Oklahoma where army cutworm also occurs.

A likely explanation for the migration is that it allows the moths a reliable source of summer flowers. Flowers provide nectar which the moths use for food. In addition, the cooler temperatures of the higher elevations may be less stressful to the moths, allowing them to conserve energy and live longer. During outbreak years, miller moth flights typically last five to six weeks, generally starting between mid-May and early June.

However, they tend to cause most nuisance problems for only two to three weeks. Exactly when the flights occur and for how long varies.

During the outbreak high populations were present from early May through mid-June. However, in , a year that also was above average for miller flights, heavy flights were not noted until early June and lasted about a month. In the warm, dry season, nuisance numbers of miller moths along the Front Range occurred over a very extended period—from late April through early July—and were concentrated around irrigated areas due to the drought.

Miller moths avoid daylight and seek shelter before day break. Ideally, a daytime shelter is dark and tight. Small cracks in the doorways of homes, garages, and cars make perfect hiding spots. Often moths may be found clustered together in particularly favorable sites. Since cracks often continue into the living space of a home or a garage, car, etc. At night, the moths emerge from the daytime shelters to resume their migratory flights and feed. The return flights mountains to the plains in early fall usually span a shorter period of time, typically beginning in the latter half of September.

However, since the majority of moths die during the summer the return flight is less obvious. The number of miller moths in late spring is primarily related to the number of army cutworm caterpillars which occurred earlier in the season. Outbreaks of the army cutworm are usually followed by large flights of miller moths. Many things influence cutworm outbreaks. Wet weather and extremely cold winter conditions may kill many of the caterpillars.

The effectiveness of natural enemies, such as ground beetles and parasitic wasps, help regulate cutworm populations. Plowing fields where cutworms develop kills many, as does tilling gardens. Miller moths may concentrate around buildings more intensively during some years. The presence of flowering plants and local humidity conditions are suspected as being important in concentrations of miller moths. The good news for anyone who cringes at the sign of a moth: because the miller moth migration is starting earlier, it will also likely end earlier.

It usually lasts up to six weeks. Skip to content. Local Business Listings. Traffic Watch. Viewhouse Sports Blitz. Friday Night Endzone. Station Jobs. Meet the Team. Contact Us. Submit Photos and Videos. Gray DC Bureau. Investigate TV. Latest Newscasts. But this year they'll be much more noticeable — and possibly a little scary to those new to the state.

The adult stage of the army cutworm, miller moths are more of a nuisance than anything else. The pests are known for leaving a trail of dust in their wake, along with surprising people by flying out from behind curtains, doorways and anywhere else they decide to momentarily settle. In addition to larger numbers in general, Cranshaw says the moths will be more centralized thanks to recent drought conditions and a mid-April freeze.

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