Individual study: Can cover crops reduce leafhopper abundance in vineyards?
Daane K.M. & Costello M.J. (1998) Can cover crops reduce leafhopper abundance in vineyards? California Agriculture, 52, 27-33
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Pest regulation: Plant or maintain ground cover in orchards or vineyards
A replicated, randomized, controlled study in 1993–1996 in four vineyards in the San Joaquin Valley, California, USA, found fewer pests and more natural enemies in plots with cover crops between the vine rows, compared to plots without cover crops between the vine rows. Pest regulation: No consistent differences were found in the parasitism of Erythroneura spp. leafhopper eggs in plots with or without cover crops between the vine rows (data not reported). Pest numbers: Fewer leafhoppers were found in plots with cover crops, compared to plots without cover crops, in seven of eight comparisons (1–36 vs 5–48 third-generation leafhopper nymphs/20–30 vine leaves). Natural enemy numbers: More spiders were found on grape vines in plots with cover crops, in one of four vineyards (data not reported). Methods: Cover crops were grown between the vine rows in a total of 19 plots (0.05–0.6 ha plots), and no cover crops were grown in a total of 19 plots (which were treated with herbicide, mown, and/or disked between the vine rows), in a total of four vineyards. Leafhoppers were sampled on 20–30 vine leaves/plot, and vines were shaken (15 seconds/sample) to collect spiders on sheets (3 x 7.3 m) or in funnels (0.9 x 0.9 m), in May–October 1993–1996.