Minimizing injury from copper fungicides

Friday, September 2, 2022


Copper damage in crucifers, lettuce and strawberry’s results in small black spots on the plants leaves. This happens when the concentration of ionic copper in the plants surpasses the plants manageable level. Copper damage is typically instantaneous with smaller damage spots. Some factors can increase the likelihood of copper damage by upping the amount of available copper on plant foliage leading to increased copper uptake. These factors include the pH of the spray solution, as lower pH values make Copper more soluble. Other factors are particle size, the frequency of application and rate of solution, water availability to the plant (more rain higher solubility of copper), age of plant tissues, product age, copper type, and finally metallic concentration of the product. All these factors play a role in the solubility of copper and the development of copper-based injuries on crop foliage. Optimizing these factors to minimize can therefore prevent copper-based injuries on crops.

By Jordan Etheridge