Grape phylloxera, Daktulosphaira vitifoliae Fitch (Hemiptera: Phylloxeridae), is a growing pest concern in the Midwest United States due to the increased planting of cold-hardy hybrid grape varieties such as 'Frontenac'. Grape phylloxera is native to North America and has been distributed to other viticultural regions of the world. In terms of foliar infestations, grape phylloxera preferentially infests many native Vitis species and hybrid grapes (e.g., V. vinifera × V. riparia) as opposed to V. vinifera. The pest's ability to asexually and sexually reproduce leads to the build-up of large populations and allows for genetic recombination. High humidity, cool temperatures, and long day length favor grape phylloxera establishment on grape foliage. Damage by grape phylloxera on foliage results in a reduction of photosynthesis and variable impacts on fruit yield and juice quality. Economic thresholds have not yet been determined, but severe foliage infestation may lead to secondary infestations by other pests. For effective management, grape growers are to examine vines for signs of galls and take management actions early in the season. Currently, chemical control is the main management method. Insecticides such as spirotetramat and fenpropathrin show the most consistent efficacy. Recommendations for insecticide use include rotating insecticides with different modes of action and combining chemical controls with cultural management tactics such as field sanitation. Following these guidelines for the use of chemical controls can help alleviate environmental concerns and ensure long-term effectiveness. Research into other management tactics such as breeding for resistant grape varieties and biological control is also needed.
- chemical control
- gall-inducing insect