Stem-borer larval infestation of ryegrass swards under rotationally grazed and cut conditions

Published source details Moore D. & Clements R.O. (1984) Stem-borer larval infestation of ryegrass swards under rotationally grazed and cut conditions. Journal of Applied Ecology, 21, 581-590.
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This study is summarised as evidence for the following.

	Action	Category
	Use grazing instead of cutting for pasture or grassland management Action Link

Use grazing instead of cutting for pasture or grassland management

A randomised experiment in 1980-1982 in Berkshire, UK (Moore & Clements 1984) found more stem-boring fly (Oscinella spp. and Geomyza tripuncta) larvae in plots of grazed vs. cut perennial ryegrass Lolium perenne (reaching peaks of approximately 3,370-5,740 vs. 985-1,770 larvae/m²) during summer and winter. Numbers were similar during late spring when adults emerged and larvae were scarce. Peak numbers of adult female flies were also higher in grazed vs. cut (approximately 165-590 vs. 75-150 flies/treatment) plots in both years. The study reported that more perennial ryegrass shoots were attacked by fly larvae in grazed (11-13%) than cut (7%) plots but more grass shoots also occurred in the former than the latter (45,000 vs. 33,000 shoots/m² respectively, at peak numbers). Three plots were sheep-grazed at 28 day intervals (beginning March 1980) and each grazing event used 20 sheep for 24 hours. Three other plots were cut with a Mayfield autoscythe on the same dates as grazing events and cut material was removed. Plots were 10 x 10 m. Fly larvae were counted by dissecting grass shoots, sampled using 50 mm-diameter turf cores (five per plot) on 26 occasions over two years. Effects on natural processes of pest control were not presented.