Influence of ground cover on spider populations in a table grape vineyard

Published source details Costello M.J. & Daane K.M. (1998) Influence of ground cover on spider populations in a table grape vineyard. Ecological Entomology, 23, 33-40.
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This study is summarised as evidence for the following.

	Action	Category
	Pest regulation: Plant or maintain ground cover in orchards or vineyards Action Link

Pest regulation: Plant or maintain ground cover in orchards or vineyards

A replicated, randomized, controlled study in 1992–1995 in a vineyard in the San Joaquin Valley, California, USA, found similar numbers of spiders and spider species on grape vines with or without cover crops between the vine rows in spring and summer. Natural enemy numbers: Similar numbers of spiders and spider species were found on grape vines with or without cover crops between the vine rows in spring and summer (15.1 vs 13.6 spiders/vine; data on species not reported). More Trachelas pacificus spiders were found on grape vines with cover crops, compared to bare soil, between the vine rows in spring and summer (7.2 vs 4.7 spiders/vine), but fewer Hololena nedra spiders were found (0.8 vs 1.2 spiders/vine). Methods: Cover crops were seeded between the vine rows in autumn 1992–1994 in ten plots (1.4 ha plots; 8 rows x 80 vines). In five treatment plots, the cover crops were mown in March 1993–1995 and allowed to regrow with resident vegetation over the summer, but in five control plots they were tilled and bare soil was maintained with herbicide (1993) or cultivation between rows and ploughing within rows (1994–1995) until mid-August. In July 1995, herbicide was used on all plots. Spiders were collected in May–September 1993–1995 by shaking the grape vines over drop cloths (two samples/plot/month, 15 seconds/sample, 9 x 3 m cloth).