Pest management in Washington vineyards has come a long way in a quarter of a century. Twenty- five years ago, pest management in Washington grapes depended on the routine application of broad-spectrum insecticides. A community of beneficial insects and mites has moved into our vineyards. Today, because we have moved away from broad-spectrum insecticides, the backbone of our pest management programs is conservation biological control (CBC).
Conservation biological control is biological control that is available everywhere and to everyone. Without it, outbreaks of leafhoppers, mealybugs and spider mites would be very large, more frequent and need chemical control routinely. Other very minor pests like scale insects would also become major issues.
Washington vineyard CBC relies upon a community of natural enemies, not just one or two species of predators and parasitoids, but an entire assemblage, comprised of specialists (preying on specific pests) and generalists able to feed on a wide spectrum of pests. Research shows that the most effective biological control is provided by the most diverse and complex communities of natural enemies.
The best thing about CBC is that it is free! The biological control agents are tiny wildlife living in our environment. The only thing we need to do is to give them access to our vineyards, and to treat them well. The most important thing we can do to treat them well is to make sure that when we use pesticides, we choose those with the least chance of harming our CBC agents. Fortunately, we have an array of chemical options, many of which are relatively safe to ‘good’ insects and mites. Always research the pesticide you use for its relative safety to beneficial insects.
What else can we do to help CBC? Research at WSU Prosser IAREC has focused on this in recent years and we have come up with two additional things you can do:
Create Better Habitat for Conservation Biological Control
Native natural enemies depend on native plants. These good insects were here long before we started growing grapes and have complex relationships with native plants. Providing the resources and refuge that these plants give enhances the ability of CBC agents to persist in or near vineyards and strengthens their performance as biocontrol agents. Many species of native plants enhance biological control services but our research has shown buckwheats (Eriogonum spp.), milkweeds (Asclepias spp.), nettles (Urtica spp.), yarrow (Achillea millefolium) and sagebrush (Artemisia spp.), have particular value.
Attract More Conservation Biological Control Agents
Research at WSU Prosser IAREC has identified wintergreen or methyl salicylate as being an effective attractant for a community of natural enemies of pests. Vineyards baited with this minty compound routinely developed larger and more diverse communities of predators and parasitoids.
Today, methyl salicylate is available commercially (http://www.agbio-inc.com/) as slow-release dispensers and is an easy and cost-effective way of enhancing CBC. Utilizing and strengthening conservation biological control, the backbone of pest management in Washington vineyards, has multiple benefits. It reduces costs of management by reducing the number of sprays, which enables the production of wine grapes with reduced synthetic inputs. This benefits both the producer and consumer.