Mark Chien, Pennsylvania State University
It’s not easy to close out a season in a vineyard. Ripe grapes are attractive to many vertebrate and insect pests. You have worked very hard starting with pruning in the frigid cold of winter, then nurturing your vines and crop through the spring rain and frost and the heat and humidity of summer and finally, six months later, the whole crop can disappear to phantom creatures in the night. It would be so nice if the harvest season could be a restful time after all the hard work to manage the vines and crop is done, but if you let down your guard now, you may lose it all. Only good planning and preparation can help to preserve the fruit so it can make fine wines.
Birds
Birds in the vineyard. From left to right. 1. Over Oregon vineyard. 2. Propane bird scare deveice. 3. Bird damage to Pinot noir. 4. Bird netting. Photos by Mark Chien, Penn State University.
Birds are often the biggest late season threat. Depending on your vineyard’s location, bird pressure can vary dramatically. If you are over a migratory pathway, like the North Fork of Long Island, birds use the vineyards as a rest and feeding stop on their way to southern destinations. This can result in devastating losses. Yet residential birds also can be a problem. In the Eastern U.S., robins and starlings are the main nuisance, but other birds such as wild turkeys also target grapes. Starlings will remove the entire berry. Robins tend to peck a berry, releasing juice and creating an opportunity for disease and insects to move in. As with all threats to the vineyard, you should know, understand, and be able to identify your enemies. Some species of birds are protected and must be left alone. You should check with your state fish and wildlife commission about the regulations governing bird control.
Bird control begins with proper vineyard planning. While it may not be practical to locate your vineyard outside a migration path, it is at least a good idea for the vineyard to be away from trees and other tall objects such as telephone poles and wires, lamp posts, and fences that can provide a roost for birds.
Bird control is mostly done at the point of conflict. There are many strategies to keep birds out of vineyards. The most common are netting and noise-scare devices. Nets are the most effective method, especially in low to moderate pressure situations. Different styles of nets include over-the-row and shoulder nets that cover only the fruit zone. The mesh patterns vary as does the strength of the material. You’ll have to find what works best against the birds that threaten your vineyard. The down sides of nets are their expense, durability (or lack of it), and the effort and expense to apply and remove the nets – some types are designed to stay on the trellis and can be used to prevent hail damage in the summer. If you are considering getting nets, you should consult growers who have used the type of netting you plan to purchase. In heavy pressure situations, even nets may fail as birds peck between the mesh, especially if nets lay on clusters – spacers can be used to push nets away from clusters.
In the past there were bird repellent products that could be sprayed on vines. Most aversion products contain materials that may compromise wine quality (e.g., garlic, methylanthranilate, etc.) since repellents must be applied near to the time when grapes are being harvested. While easy to use, their effectiveness is doubtful.
Noise makers such pyrotechnic and electronic scare devices are very common. Propane cannons make a loud blast that scares birds and humans alike. They can be very effective, but need to be moved around since birds will adapt to their use. More growers are using electronic bird scare devices because their sound is less noxious or startling than the cannons. You will find proponents and detractors of both systems. Propane tanks last a finite period depending on blast frequency, and are clumsy and inconvenient to fill. The electronic devices usually run on a 12V battery or can be set up on a solar charger. It is important to get these systems (including nets) in place and operating before the birds arrive in the vineyard. Once they identify a source of food it is very hard to chase them out.
Other devices such as fake owls, real owls, scary eyes, mylar tape, and scarecrows are not very effective. If nets are not used, the best results are usually achieved by a combination of devices that may include dawn and dusk bird patrols on ATVs with noise devices (starter pistol, shotgun, etc.). Be sure to check with the fire marshal about the legal and proper use of pyrotechnic devices for bird control on farms, to avoid starting a wildfire.
Deer
Deer in the vineyard. Damage (L) and fencing.
Deer will browse tender shoots of new vines and shoots in older vineyards throughout the growing season, but they also can be a nuisance at harvest. Most of the old wives’ tale methods of control ― such as blood meal, human hair, and Irish Spring soap ― do not work. As with birds, a vineyard setting away from wooded areas is preferred. But if deer are a problem, exclusion is the best remedy. In the case of almost every vineyard in the Eastern U.S. and some in the West, a stout wire mesh fence is necessary. Deer will browse on tender shoots in the spring, which can set a new vineyard back an entire season. At harvest, they can cause severe yield losses. An exclusion fence should be part of the basic vineyard development budget. Fencing varies in type, strength, and cost, so some research is necessary to determine what will work best on your site and budget. State fish and wildlife commissions sometimes have cost-share funds available for fencing materials.
Some growers use a temporary system, leaning wire mesh fencing against the end posts and anchor wires to prevent deer from walking into the vineyard. If tractor access is needed the fence can be quickly removed and laid on the ground. In the case of large vineyards, fencing may not be practical and other control strategies may need to be used.
Noisemaking devices used to scare birds will have some effect on deer. Hunting can help to control local deer population but adding firearms onto the farm is simply another safety risk in an already challenging work environment. If hunting is permitted, check with the state game commission to make sure you comply with hunting regulations and proper disposal/use of game.
Recommended Resources
Deer Control in Vineyards, University of Kentucky
Vineyard Deer Management, University of Maryland
Reviewed by Ed Hellman, Texas AgriLife Extension and Jim Wolpert, UC Davis