By: Cheryl Gray
No vineyard wants to watch its profits disappear. Yet, left undetected, pests can feed and multiply on the fruit, vine, leaf, root and even the soil of vineyard plants. While many of these threats are undetectable to the naked eye, the end result is all too visible. Pests multiply, spread disease and ultimately cost vineyards money through lost crops and vineyard plants.
Scientists have long considered what methods work best for grape growers who want to protect their crops without harming the environment. Multiple studies have been published, including those from the National Center for Biotechnical Information, which is under the umbrella of the National Institutes of Health. Those studies point to multiple defense strategies, specifically, ways to increase the populations of natural predators as well as the controlled use of biochemicals. These methods aim to destroy microorganisms and pests by targeting their ability to reproduce. The first and most important rule of engagement is knowing the enemy.
Among the most destructive pests for vineyards are mealybugs. Experts say these culprits can travel from vineyard to vineyard, sometimes on equipment, vineyard workers or by whatever means they can hitch a ride. The first stop for these pests is usually the vine trunk wood, where they set up during the winter. As early as spring, the mealybugs make their way onto the canopy. Before long, they wind up on the grapes, where they infect the fruit with egg sacs and larvae. Left uncontrolled, mealybug infestations can not only reduce crop yield but can also lead to plant stress and, ultimately, plant death.
Scientists say that natural enemies of these vineyard wreckers include a predator beetle known as the “mealybug destroyer.” Its scientific moniker is Cryptolaemus Montrouzieri. Another natural predator is a parasite known as the Anagyrus wasp. Both are produced by the millions each year by a California cooperative, Associates Insectary, which specializes in integrated pest management systems.
Associates Insectary, founded in 1928, brands itself as the only producer of the mealybug destroyer beetle in the United States. The co-op, headquartered in Santa Paula, California, says it has the capability to ship these and other beneficial insects not only to its regional customers but also to global markets throughout North America, Central America and Asia.
How does IPM work in the vineyard using natural predators? For mealybug control, the battle is all about appetite. The mealybug destroyer beetle basically eats through an infestation of mealybugs, feasting on every stage, from egg sacs to larvae to fully grown pests. The female beetles lay more than 400 eggs, making for a ready army to combat mealybugs.
Unlike the Anagyrus wasp, in which only the female wasps attack mealybugs (by laying eggs inside them), an entire “family” of mealybug destroyer beetles – male, female, juvenile and adult beetles—literally feed on these pests. Many IPM programs use a combination of the destroyer mealybug beetle and the parasitic wasp to fight mealybugs.
Another benefit to deploying mealybug destroyer beetles in the vineyard is that they go undetected by ants, which have a symbiotic relationship with the mealybug. Again, it is about one insect feeding off another. Ants consume the honeydew that the mealybug secretes, the same honeydew that can destroy grapevines. In exchange for an unending food source, the ants defend mealybugs from other predators – all except the mealybug destroyer beetles.
Controlling the ant population that defends its mealybug “meal ticket” is a separate challenge for vineyards. Among the most destructive ant species to vineyards is the Argentine ant, which became more prevalent in California vineyards during the late 1980s. Containing an ant population in the vineyard usually requires a controlled chemical application, including bait systems and spray options.
The Entomological Society of America (ESA) has published studies about the Argentine ant and its impact on vineyards, particularly in California. As the largest organization of its kind in the world, the ESA is focused on serving the professional and scientific needs of entomologists and individuals in related disciplines. This, of course, includes grape growers who need to know how to rid their vineyards of pests without harming the environment.
In the case of Argentine ants, experts say it is important to recognize that ant colonies operate with a hierarchy all their own. While chemical sprays can kill or repel forager ants, the ones that go out for food, those ants are easily replaced with other foragers. Moreover, entomologists note that foraging ants comprise only a small number of ant colonies. This means that spray applications may be somewhat limited in that they are not likely to affect either the queen ants or larvae protected within the ant colonies. The other downside of sprays is that some chemicals can break down within 30 days and harm beneficial insects and the environment.
Experts say that baits offer an alternative to sprays. Many contain a slow-acting insecticide with the idea that once an ant comes in contact with the bait, it will bring that bait back to the nest, expose it to other ants and, as a result, more ants die. The added plus is that the small amount of insecticide in baits is unlikely to impact either the environment or the natural predators that attack mealybugs and other pests.
Suterra is an Oregon-based company that specializes in providing a comprehensive IPM program that includes controlling ants in the vineyard with bait deployment. The type of bait and overall treatment is contingent upon the species of ant being treated and the location of the vineyard.
Suterra produces hundreds of products that are used by its agricultural clients worldwide, including more than 400,000 acres just in the state of California. Part of its lineup includes products manufactured to disrupt the mating pattern of mealybugs by imitating chemicals known as pheromones. Pheromones are naturally occurring chemicals emitted by organisms that allow them to connect within the same species. The chemicals serve multiple functions, including searching for food sources, identifying potential dangers and finding a potential mate.
Suterra’s Celada™ VMB vapor dispenser works by deploying a continuous synthetic pheromone release that is designed to disrupt the mating pattern among mealybugs. The idea is to confuse the males by keeping them away from the females of the species. The Celada™ VMB vapor dispenser lasts for a full year and is designed to blend into the vineyard with its unique color and shape. Suterra has other products designed to disrupt the mating patterns of mealybugs, such as CheckMate® VMB-F, a sprayable microencapsulated formula and CheckMate® VMB-XL, a membrane dispenser. The active ingredient in both products is a synthetic replica of the sexual reproduction pheromone of the mealybug.
When vineyards consider what equipment to use to combat pests, multiple factors come into play, such as vineyard size, specific needs and, of course, how much of its budget is devoted to pest control. Spray Innovations has answers. The company,
headquartered in Grand Island, Nebraska, not only services the cattle industry but also other agricultural sectors, including grape growers. It has been
operating for some 40 years. Chris Whiting is the sales manager for the company and shares details about some of its popular products and how they save time and money for clients.
“Our most popular sprayers for vineyards are our 10-nozzle dual volutes,” Whiting said. “This volute allows the grower to drive down the row and spray both sides with one pass, reducing time in the field. We have several models available in our Little Hercules engine-driven line (rope or electric start versions available) and our PTO-driven line.”
He went on to share, “Our sprayers are all built in-house at our Grand Island, Nebraska location. We fabricate 90 percent of the parts that go into our sprayers, which cuts down on costs. We sell most of our sprayers directly, so there is no middleman, and we can keep the cost down. Our frames are powder-coated and include a 10-year warranty. Our volutes are all made with galvanized sheet metal, which is more rigid and can take more abuse than volutes made out of plastic.”
Customers of Spray Innovations include Krista Hartman, co-owner of Red River Wines and Provisions at the Hartman Vineyard in Sadler, Texas. She gives the Spray Innovations P-D15-611 Mist Sprayer a “thumbs up” for performance.
“The fine mist and powerful fan system deliver uniform and thorough coverage with all my spray program products,” Hartman said. “I love how I can turn off either volute individually for end rows or a specific target area if needed. This was a big investment for my small vineyard operation, and well worth it. I save time, use less product, feel safer while spraying and keep my canopy as healthy as the elements allow, thanks to this terrific machine.”
Whether using chemical applications or natural predators, grape growers can deploy an arsenal of weapons to fight vineyard pests from fruit to root. Understanding timing, weather, equipment use and appropriate application of either biochemicals or the release of natural enemies all affect results.
