This alert excerpt was taken from Dr. Acimovic’s article entitled: Get Ready To Apply Delayed Dormant Copper With Oil in 2019
“CAUTION: if frosts are predicted to occur or have occurred after green tissue emerges from buds, be very cautious of applying oil mixed with copper near frost events. This is especially necessary if frost/s occur when buds are near the half-inch green i.e. significant amount of green tissue is exposed. In these cases, avoid spraying copper in mix with oil before or after announced frost conditions. Both oil or copper alone, but even more in a mix, can cause leaf and fruit cluster injury due to high rate of uptake i.e. suction of these products into the green tissue wounds opening while ice melts. The mix is more damaging because oil acts as a penetrant and improves further uptake of copper in an already frost injured tissue. The best option is to leave a several days break before or after the frost event/s.”
