Fruit Crops

Granulosis Virus For Codling Moth Control

The granulosis virus of the codling moth (CpGV, for Cydia pomonella, the scientific name of codling moth) has been tested in field trials many times. In some trials the virus has provided better crop protection than broad-spectrum chemical insecticides, and in others the chemicals were better. In this study the effectiveness of CpGV was compared on apples in Ontario, Canada where there are two generations of codling moth per year, with that in Nova Scotia, where there is only one generation per year. The use of the virus in conjunction with chemical insecticides was also examined.

Where the climate is cool and the growing season short, female codling moths lay fewer eggs and many of the eggs or resulting larvae are killed by natural enemies. Under these conditions CpGV needs to be applied only once or twice per year for good fruit protection. However, in warmer areas with a longer growing season, codling moth populations tend to be higher and larval activity occurs over a longer period of time, necessitating several applications. Six or seven applications were made on some Ontario orchards to keep fruit damage below 4%. As in previous studies, the virus was not consistently as good as or better than chemicals at keeping codling moth damage at low levels.

This granulosis virus can also be used as a replacement for mid- and late-season organophosphate insecticide applications to minimize insecticide residues on fruit and to conserve beneficial natural enemies in the orchard. CpGV would be especially useful in organic production of apples.

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