Managing Vineyard Insect and Mite Pests
Green June Beetle
Green June beetle (Cotinis nitida) is a serious pest most commonly found in southern vineyards, although this native beetle can be found from Connecticut south to Florida and as far west as Texas and Oklahoma.
Symptoms
Green June beetle is a serious pest of grapes feeding on petioles, leaves, and berries (See Figure 22.18). Green June beetle is attracted to the ripening clusters as the berries soften and the sugar content increases. As the beetles feed, they emit pheromones, which attract other green June beetles.
Life Cycle
The larvae overwinter just below the soil surface. In the spring, they tunnel near the soil surface, pupate and emerge as adults in the summer months feeding on leaves and berries. Adult populations usually peak with grape berry maturation.
Monitoring
Management of green June beetle requires frequent scouting to detect its presence in the vineyard at the time they are most active. Traps are available for monitoring green June beetle though not too effective, but still can be used to indicate initial adult emergence.
Cultural Pest Control
Growers might consider burying the pupae by mounding soil up under the vines early in the season.
Biological Pest Control
Parasitic wasps and flies have also been used to control green June beetle. Two species of tiphiid wasps (Tiphia vernalis and T. popilliavora) have been introduced to control green June beetle larvae.
Biorational Pest Control
Microbials
Milky spore disease (Bacillus popilliae) is available for the control of green June beetle, but it is only effective in protecting grassy areas from large larval populations; winged adults will continue to enter vineyards from untreated areas.
Chemical Pest Control
Standard chemicals for controlling green June beetle include Imidan (phosmet), Danitol (fenpropathrin), Guthion (azinphos-methyl), Sevin (carbaryl), and Sniper (bifenthrin). Insecticides used for controlling green June beetle in vineyards are presented in Appendix K, Insecticides Registered for Use in Vineyards.
Applying Control Materials
Green June beetles are most abundant in the vineyard from when winegrapes are high in accumulated sugars and until grapes are harvested. However, the products that are effective against these pests have required pre-harvest intervals (REIs) that prohibit their use in the final few days before harvest.
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