Oviposition of Black Cutworm (Lepidoptera: Noctuidae) on Creeping Bentgrass Putting Greens and Removal of Eggs by Mowing

Oviposition and egg location of black cutworm, Agrotis ipsilon (Hufnagel), removal of eggs by mowing, and survival of eggs on grass clippings were evaluated on a creeping bentgrass, Agrostis palustris Hudson, golf putting green. Caged moths laid similar numbers of eggs on bentgrass maintained at cutting heights of 3.2, 4.8, or 13.0 mm. Nearly all eggs were laid singly on the tips of grass blades. In 3 trials, mowing of plots 48 h after oviposition removed an estimated 75-91% of the eggs at the 3.2-mm cutting height, and 81-84% at the 4.8-mm cutting height. In another test, 97% of marked eggs on grass blades were recovered on clippings in the mowing basket. Five to 10% of the eggs were dislodged from grass blades by the mower roller. Survival of eggs on grass clippings harvested with the greens mower was as high as 90% in the laboratory and 50% in the field. This study suggests that daily mowing removes most black cutworm eggs from golf putting greens, implying that larger cutworms found on greens may originate from surrounding, high-mowed turf. Disposal of clippings away from greens may be important for reducing reinfestations by crawling larvae.