Treatment Plan

Sensitivity to copper fungicides varies among grapevine cultivars, refer to copper sensitivity charts published in university pest control guidelines; information is lacking for some varieties. Copper sulfate is more injurious than other forms of copper such as “fixed” copper formulations such as copper hydroxide, the active ingredient in Kocide and Champ. Copper injury is more likely when drying conditions are slow, it is advisable to spray copper under good drying conditions such as hot and dry. Spray water pH also plays a role in the potential for injury, with greater injury occurring at lower pH (below 6.5 to 7). Follow product guidelines for the addition of agricultural spray lime provided on product labels. Copper fungicides have been used for hundreds of years and there is no possibility of disease resistance development. Many growers use copper late in the season when some disease may be present without the potential for disease resistance development associated with many modern fungicides, and this use may slow late season development of downy mildew (especially) and powdery mildew and result in lower inoculum levels in the subsequent growing season.

Copper fungicides provide good activity against downy mildew, some activity against powdery mildew (but should not be relied upon for powdery mildew control on susceptible varieties), and only moderate control of black rot, with low risk of disease resistance development.

Apply Dupont Kocide 3000 at 0.75-1.75 lb per acre per application, do not apply more than 66.7 lb per season. Foliar injury may result on copper sensitive varieties, either test for sensitivity or add 1 to 3 pounds of hydrated lime per pound of product. Slight to severe foliar injury may occur in copper-sensitive varieties, use the lower rate of this product and test for copper sensitivity when treating copper sensitive varieties. Consult University pest management guidelines for varietal sensitivity to copper. Slow drying conditions (cool or humid) may increase copper sensitivity; apply when foliage is dry and drying conditions are good. 0 day PHI,  48 hr REI.

Apply Champ Formula 2 Flowable at 1.33 to 2.66 pt per acre per application, do not apply more than 55 pt per acre per season. Slight to severe foliar injury may occur in copper-sensitive varieties, use the lower rate of this product and test for copper sensitivity when treating copper sensitive varieties. Hydrated lime may be added at 0.5 lb per 100 gallons of spray solution to decrease the severity of phytotoxicity. Consult University spray guidelines for varietal sensitivity to copper. Slow drying conditions (cool or humid) may increase copper sensitivity; apply when foliage is dry and drying conditions are good. 0 day PHI, 48 hr REI.