Grapes

A list of resources for Grape Pest and Weed Management

Multi-small fruit spray program for the control of major small fruit pests and diseases.

It is critical to properly monitor and assess fruit maturity characteristics to make the appropriate management, harvesting, and winemaking decisions to produce the best quality grapes and wine possible. The first step to assessing ripeness and quality is to take a proper sample that best represents the actual ripeness stage of the cultivar in that block of the vineyard. The best way to achieve this is to collect a sample that is random, unbiased, and representative.

Downy mildew is now a year-long challenge for grape growers in the East. Downy mildew is often difficult to manage because it requires specific weather conditions to become a serious threat, but it can develop into an epidemic very quickly in favorable weather.

Botrytis is a major disease threat as harvest approaches. Botrytis cinerea is a fungus that affects many plant species, especially wine grapes, where it is commonly known as Botrytis bunch rot or gray mold.

The grape root borer (GRB), Vitacea polistiformis (Harris), is an insect pest native to the Eastern United States. Its range is from the central Midwest (west) to the Atlantic Ocean (east) and from Florida and Texas (south) to Vermont and Michigan (north). GRB is a pest of all commercial grape types and feeds on native Vitis. It has a long life cycle and takes many years for it to do significant damage to grapevines. However, once grape root borers are present in a vineyard, the unlimited susceptible food source can dramatically increase the infestation. The grape root borer effect may not be immediately apparent on the vines, but once the number of larvae reaches a sufficient level, damage can be significant. Because it is an ("invisible") root tunneling pest, many growers are unaware of the economic damage being caused by GRB.

Timely Viticulture is an electronic newsletter designed to remind grape producers of seasonal vineyard needs and considerations throughout the year.

At 3 to 4 weeks after bloom, the risks of black rot (BR), Phomopsis (Ph; including cane and leaf spot, and fruit rot), and powdery mildew (PM) are decreasing. Downy mildew (DM) will be the main threat. While most Botrytis bunch rot infections occur around bloom and fruit set, bunch closing and veraison may also be critical points for protection when weather conditions are favorable for infection, especially on susceptible varieties.

University of Delaware extension and Rutgers both as recently reported seeing a large increase in green stinkbugs (Acrosternum hilare or Chinavia hilaris ) in their black light traps.

Although many grape diseases do not show actual symptoms on the foliage or fruit until later in the season, it is imperative that disease management begin shortly after growth begin in the spring. Early season foliar and fruit diseases (Phomopsis, Powdery Mildew, Downy Mildew, and Black Rot) become established on the young foliage and spread to new foliage and developing cluster as growth continues.