Project Overview
Annual Reports
Commodities
- Fruits: grapes
Practices
- Pest Management: mating disruption
Proposal summary:
The grape root borer is an insect pest native to the Eastern U.S. The larval stage of the moth can do significant damage, living at least three years and possibly longer in the soil feeding on grape roots. They can destroy and kill mature grape vines. It takes years for the borer to reach population levels that cause economic damage. Twenty years after planting, grape production can be reduced by up to 70%. The most widely used control method involves using a restricted-use organophosphate pesticide, which is expensive and time consuming. Recently a new pheromone system has become available for use in grape root borer mating disruption.The goal of this project will be to test the effectiveness of Isomate GRB, a newly approved product, to reduce or eliminate grape root borer populations. The life cycle of grape root borer presents special challenges. The larval stage that destroys grape roots can remain underground for one, two or possibly even three years before becoming an adult and appearing above ground. Because of its variable multi-year life cycle this project will have to be undertaken for at least three years. This system utilizes a pheromone mix of a different species that differs from the ingredients in the standard grape root borer pheromone lure. Each of the new pheromone dispensers contains 80 times more pheromone than the standard grape root borer pheromone lure currently available. The new dispensers are supposed to be placed in the vineyard at a concentration that releases 300 times more pheromones than the standard pheromone lures used in our previous SARE projects. Grape root borer populations in our vineyard never decreased utilizing the standard pheromone lures in previous projects. The aim of this multi-year project will be to test the new system at different rates and its effectiveness in reducing or eliminating grape root borers in our vineyard. Results will be presented at several field days, grape grower meetings, in printed materials, through extension and on the Web.
Project objectives from proposal:
A new pheromone system for the control of grape root borer has recently been introduced, but the pheromone mix is that of another moth species, not grape root borer. Only one report of the use of this new pheromone mix for the control of grape root borer has been published and this research was done in Florida. The new pheromone system was tested for two years, but no testing was done in the third year to determine if the grape root borer population had actually decreased. The study used trap shutdown as an indicator of success, but noted that “trap shutdown alone does not prove that mating disruption has occurred.” A minimum concentration of the new pheromone mix required to control grape root borer has not been established and neither has the rate at which the new pheromone mix is depleted in the vineyard.
The goal of this project will be to test the effectiveness of Isomate GRB, a newly approved product, to reduce or eliminate grape root borer populations. The life cycle of grape root borer presents special challenges. The larval stage that destroys grape roots can remain underground for one, two or possibly even three years before becoming an adult and appearing above ground. Because of its variable multi-year life cycle this project will have to be undertaken for at least three years. It takes years for the borer to reach population levels that cause economic damage. Twenty years after planting, grape production can be reduced by up to 70%. The most widely used control method involves using a restricted-use organophosphate pesticide, which is expensive and time consuming.
Since 2002 pheromone traps have been utilized every year to determine the size of the grape root borer population. This record of population size will allow the project to determine if the use of Isomate GRB can truly reduce grape root borer populations. Every year since 2003 the vineyard has been divided into the same plots and blocks of a randomized complete block design for the placement of pheromone traps and to allow for statistical analysis of the data.
Trap shutdown of grape root borer pheromone traps was achieved in Florida with 257 dispensers per acre. The current label for Isomate GRB suggests 100 dispensers per acre. This number is based on results from pheromone dispensers for other species but not grape root borer. No research has been done to determine the minimum number of dispensers needed to achieve mating disruption for grape root borer. Initially the number of dispensers placed in the vineyard will be low. If any adult male grape root borers are captured, the density ofdispensers will be increased. If any adult male grape root borers are captured with this treatment level the number of dispensers will be increased again. This system will be followed until total trap shutdown is achieved. The Isomate GRB dispensers will be evenly distributed in their respective plots. By this method the minimum number of dispensers required per acre to achieve trap shutdown will be determined.
The pheromone dispensers work by the volatilization of the pheromones present. The rate at which Isomate GRB dissipates into the air has not been determined. This information is required to know how long the dispensers will last and be effective. At least four Isomate GRB dispensers will be placed at another site and weighed weekly to determine the rate of pheromone loss.
Pheromone traps will also be placed outside of the vineyard to reveal if a zone of mating disruption extends beyond the vineyard due to the extremely high concentration of pheromones released by the dispensers. Grape root borer traps will be placed in four directions away from the vineyard. They will roughly be north, east, south and west. The traps will extend 1000 feet from the vineyard and one trap will be placed every 200 feet.
In the second year of the project, Isomate GRB dispensers will be placed in the vineyard at the rate that was found to be the most advantageous during the first year. Each plot will also receive a pheromone trap to monitor the presence of grape root borers. If any grape root borers are captured the number of dispensers will be increased to higher treatment levels. Pheromone traps will again be placed outside the vineyard to ascertain if a zone of pheromone influence extends beyond the vineyard.
In the third year no Isomate GRB dispensers will be placed in the vineyard. The pheromone standard traps will be placed in the center of each plot to capture male grape root borers that emerge in the vineyard. By the third year if the pheromone dispensers have reduced the population of grape root borers due to mating disruption very few moths should be captured. Pheromone traps will also be placed outside the vineyard to try to determine if any grape root borers are entering the vineyard from other locations. The total number of moths captured can be compared to the average number captured from 2002 to 2012 to ascertain if the reduction is statistically significant.