Abstract
Second-instar cabbage loopers, Trichoplusia ni (Hubner), were applied to cv. Packman broccoli, Brassica oleracea var. italica Plenck, grown in Montgomery County, Va. Insects were applied at the 5-8-leaf stage for three planting seasons. Means of 8.4 cabbage looper larvae per plant in spring and 12.1 in fall 1986 caused 29.5 and 55.1% defoliation, respectively, but did not influence yield (head weight) significantly. Under suboptimal planting conditions in spring 1987, head weight decreased linearly with increasing numbers of cabbage looper larvae. Head weight resulting from 0.03 cabbage loopers (1.05% defoliation) was greater than the head weight resulting from 7.36 cabbage loopers (30.95% defoliation). The mean harvest date was influenced by the number of cabbage loopers or the percentage of defoliation in each season, but the maximum difference between treatments within a season was only 2.7 d.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
