Responsible use of insecticides means understanding the unique qualities and spraying procedures for different active ingredients. Fruit trees are regularly sprayed with synthetic and organic insecticides. Before selecting a spray for your fruit tree, scrutinize the product labels. Note application rates, spray schedules and the weather requirements for applications. When the importance of any of these factors is neglected, insecticides will burn fruit trees.
Insecticide labels state the maximum temperature at which they should be applied. Sometimes this is because of the type of soap or oil contained in the insecticide, and other times it is because of a specific chemical. In any case, when this rating is not adhered to, fruit tree leaves and the fruit itself can be damaged. Too much humidity causes insecticides to burn fruit trees, because the liquid spray stays wet on the leaves for longer than normal.
An insecticide's viscosity can cause it to burn fruit trees. A thick product sticks to plant surfaces for much longer than thinner ones. In some cases this is desired and additives are used in insecticide concentrates to encourage this property. It becomes a problem when those applying these products don't take into account sudden increases in temperature or sunlight.
Fruit trees are burned when insecticide is mixed too strong or applied too frequently. Do not assume that more is better. You will stress your fruit tree and make it more vulnerable to future insect attacks. Don't spray insecticide on plants around fruit trees on windy days. Drift can land on your fruit tree, kill pollinators and burn the plant. The distance which chemical molecules travel depends on wind speed and the force of the spray. Just because a product is organic does not mean that any less attention should be paid to label instructions. Natural insecticides often contain botanical oils that quickly burn fruit tree leaves if applied in hot sunny weather.
Fruit trees damaged by pesticides exhibit specific symptoms. Leaves look burned, distorted or curled. Badly damaged leaves drop and small branches might die back. The characteristics of pesticide injury can be mistaken with an iron deficiency. Pesticide injury is recognized by the spray patterns that appear. It is often obvious which areas of the fruit tree were hit and which were missed. Individual leaves display bands of light areas and are sometimes spotted where drops of pesticide have landed.
Always evaluate whether it is necessary to spray insecticide on your fruit tree. Identify bugs to determine what if any damage they will cause. Unnecessary use of insecticides on fruit trees is costly and potentially detrimental to overall plant health.