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Individual study: The effect of an irrigated buckwheat cover crop on grape vine productivity, and beneficial insect and grape pest abundance in southern California

Published source details

Irvin N.A., Bistline-East A. & Hoddle M.S. (2016) The effect of an irrigated buckwheat cover crop on grape vine productivity, and beneficial insect and grape pest abundance in southern California. Biological Control, 93, 72-83


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

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

A replicated, randomized, controlled study in 2008 in an irrigated vineyard in southern California, USA, found more crop damage, more pests (leafhoppers), and more natural enemies in plots with cover crops, compared to bare fallows. Crop damage: More grapes were damaged by bees or wasps (2% vs 0% of grapes were broken) or thrips (in one of four comparisons: 28% vs 18% of grapes were scarred) in plots with cover crops, compared to bare fallows. Pest numbers: On sticky traps, similar numbers of pests were found in plots with cover crops or bare fallows (110–220 vs 110–140 combined pest insects/side). On grape leaves, more leafhoppers were found in plots with cover crops, compared to bare fallows, in one of four comparisons (22 vs 7 insects/leaf). Natural enemy numbers: On sticky traps, more natural enemies (predators and parasitoids) were found in plots with cover crops, compared to bare fallows, in one of eight comparisons (620 vs 310 combined beneficial insects/side). On grape leaves, more predators were found in plots with cover crops, compared to bare fallows, in two of four comparisons (23 vs 1–2 insects/leaf). Methods: Cover crops (Fagopyrum esculentum buckwheat) were sown between the vine rows in four plots, in summer 2008, and the cover crops were irrigated throughout the summer (sprinklers: 10 sprinklers/plot, 45 litre/hour, two hours after sowing and six hours every 7–10 days; tree sprayer: 60.5 litres/plot, thrice/week). This irrigation system was also used on three plots that did not have cover crops. Conventional management was used on six plots (bare fallows were maintained between the vine rows through cultivation and no irrigation). The plots had two vine rows each (28.7 x 6 m plots). Pests and their natural enemies were sampled with transparent sticky traps (two traps/plot, 16.7 x 13.2 cm, 145 cm above the ground, collected and replaced every week, 10 June–19 August 2008) and by observing grape leaves (five leaves/plot, observed every two weeks, 5 June–2 August 2008). Grapes were harvested in September 2008 (10 clusters from 3 m in the centre of each plot).

 

Crop production: Plant or maintain ground cover in orchards or vineyards Mediterranean Farmland

A replicated, randomized, controlled study in 2008 in an irrigated vineyard in southern California, USA, found larger grapes in plots with cover crops, compared to bare fallows, but found similar grape yields and sugar contents. Crop yield: Similar grape yields were found in plots with cover crops or bare fallows (75–80 vs 55 g/cluster). Crop quality: Similar amounts of sugar were found in grapes from plots with cover crops or bare fallows (24 oBrix/cluster). Larger grapes were found in plots with cover crops, compared to bare fallows, in two of four comparisons (11 vs 10 mm diameter). Methods: Cover crops (Fagopyrum esculentum buckwheat) were sown between the vine rows in four plots, in summer 2008, and the cover crops were irrigated throughout the summer (sprinklers: 10 sprinklers/plot, 45 litre/hour, two hours after sowing and six hours every 7–10 days; tree sprayer: 60.5 litres/plot, thrice/week). This irrigation system was also used on three plots that did not have cover crops. Conventional management was used on six plots (bare fallows were maintained between the vine rows through cultivation and no irrigation). The plots had two vine rows each (28.7 x 6 m plots). Grapes were harvested in September 2008 (10 clusters from 3 m in the centre of each plot).