Journal of Economic Entomology (2013) 106, 905-911

Craig R. Roubos, Keith S. Mason, Luís A.F. Teixeira and Rufus Isaacs (2013)
Yield-based economic thresholds for grape berry moth (Lepidoptera: Tortricidae) in juice grapes
Journal of Economic Entomology 106 (2), 905-911
Abstract: A 3-yr field study was conducted at commercial juice grape (Vitis labrusca L.) vineyards to develop an economic injury level (EIL) for grape berry moth, Paralobesia viteana (Clemens) (Lepidoptera: Tortricidae) and to determine patterns of cluster injury. Infestation of grape clusters by P. viteana was measured biweekly from bloom until harvest, and fruit was sampled immediately before harvest to determine the yield and level of fruit injury by this pest. Comparison of fruit infestation at each sampling date to that found just before harvest revealed stronger relationships over time, and by early August at least 50% of the variation in preharvest infestation was accounted for by previous infestation. Grape yield declined with increasing infestation by P. viteana, allowing calculation of the EIL at which the value of yield lost to infestation equaled the cost of insecticide applications to prevent the infestation. Using two scenarios of pest control programs based on pyrethroid or diamide insecticides, the EILs were calculated to be 9.9 and 17.7% of clusters damaged, respectively. For use in juice grape vineyard integrated pest management programs, we propose using 5 and 10% damaged clusters at harvest as action thresholds for further testing in field trials to evaluate sampling plans and the use of thresholds to guide vineyard pest management decision-making under different insecticide scenarios.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Craig R. Roubos, Rufus Isaacs

Research topic(s) for pests/diseases/weeds:
damage/losses/economics
thresholds/decision-support systems

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Paralobesia viteana	Grapevine (Vitis)