Vineyard IPM scouting report for May 12-19, 2014

Insect and disease development remains slow in Southwest Michigan vineyards.

Grape flea beetle adult. Photo credit: Steven VanTimmeren, MSU

Grape flea beetle adult. Photo credit: Steven VanTimmeren, MSU

As part of the continuing Michigan State University Vineyard IPM Project that is supported by the Michigan Grape and Wine Industry Council and National Grape Cooperative, Michigan State University Extension will provide biweekly scouting reports of insect and disease incidence at commercial vineyards in Southwest Michigan. These reports are written to inform growers, vineyard managers, crop consultants and other grape industry members of current pest and disease occurrence, and to help them plan for scouting and management of vineyards. These summaries should not be used as a substitute for scouting your own vineyards, but should be used as a guide for when particular pests and diseases are likely to occur.

Growing degree day summary (GDD50 from March 1)

The reports will include weekly updates of Michigan State University Enviro-weather GDD accumulation including the estimated GDD accumulation for the week ahead. We are currently running well behind the 2013 spring.

Enviro-weather site

May 17

May 25 (projected)

Berrien Springs

236

304

Lawton

224

310

Berrien County farms, visited Monday, May 19

As of May 19, Concord is at 5- to 7-inch shoots and Vignoles are at 1- to 3-inch shoots. Over the past three weeks, damage from cutworms or flea beetles was not observed at sites we visited. Although the impact of flea beetle feeding is greatly reduced after shoots reach 1 inch, flea beetles lay eggs on developing shoots and their developing larvae can feed on the leaves. Vineyards with a history of flea beetles should be scouted until bloom to identify if excessive damage is occurring and to locate possible problem areas for next season.

Low numbers of grape berry moth males have been captured in pheromone traps at all sites, one to eight moths per trap. This indicates the start of the first generation of this pest, but no action for control of this pest is necessary at this time. At the farms we visited, the first fungicide cover sprays targeting phomopsis, powdery mildew and anthracnose are being applied. No disease symptoms were seen at these vineyards during scouting on May 19.

Van Buren County farms, visited Monday, May 19

On May 19, Concord and Niagara were at 3- to 6-inch shoots and Chancellor was at 2- to 4-inch shoots. On May 7 before bud break, very low incidence of flea beetle feeding damage was observed in two Concord vineyards below any economic levels. One site in Lawton, Michigan, had 1/200 buds, or 0.5 percent, fed upon, and the other had 3/200 buds, or 1.5 percent, fed upon. Adult flea beetles were also present in these vineyards on growing shoots on May 13 and May 19. These vineyards will be monitored for subsequent feeding damage from flea beetle larvae.

Grape berry moth males were captured at all the farms we visited in Van Buren County and the number caught in traps ranged from four to 97. No action for control of this pest is necessary at this time.

The first fungicide cover sprays targeting phomopsis, powdery mildew and anthracnose are being applied. No disease symptoms were seen at these vineyards during scouting on May 19.

Drs. Issacs and Schilder’s work is funded in part by MSU’s AgBioResearch.

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