What to Do if Hail Hit Your Vineyard

If you were hit by a hailstorm on May 22nd, as we were at RAREC, you are probably making some hard decisions on what to do in the vineyard.

Hail-damaged Cordon on Grape Vine

Hail-damaged cordon on a grape vine at Rutgers Agricultural Research and Extension Center. Shoots, leaves, and flower buds were severely damaged and most shoots were broken off.

Removal of dead and compromised leaves and flower clusters will help reduce development of fungal pathogens.

Stem wounding will be a big concern especially for vineyards with crown gall. Treatments that aid in wound healing or have bactericidal effects may provide some help. However, shoots severely damaged by hail may need to be pruned out.

New growth will continue to push as weather conditions allow. This new growth should be protected against black rot, powdery and downy mildews as you would in any other year.

[Read more…]

Grape Injury
from Captan Mixed with Oil-containing Products

Fig 1 Captan induced Leaf Necrosis in Grape

Fig 1 Captan mixed with oil-containing product
induced leaf necrosis in grape

When used properly Captan is a safe and effective fungicide that plays an important role in grape disease control and fungicide resistance management, but it is crucially important to never apply Captan mixed with oil or close in time to the application of any oils. The active ingredient in Captan cannot easily penetrate into the plant, but when it does it can be very toxic, especially to grapes. Injury from this type of spray combination has been reported in blueberries and there are many anecdotal reports of less severe phytotoxicity in other fruit crops. By comparison, the damage to grapes can be very severe and the symptoms include leaf necrosis, longitudinal stem splitting and vine death (Fig. 1, 2, 3). Sadly, experience has shown that under the appropriate conditions a single spray of Captan with an emulsifiable concentrate insecticide can kill an entire vineyard. [Read more…]