What Are the Symptoms of Phytotoxicity in Fruit Trees? A Detailed Guide to the Latest Remedial Measures
Fruit is a common food in our daily lives and one of the sources of supplemental nutrients. However, during fruit tree cultivation, pest and disease damage is unavoidable, and many fruit growers use pesticides for control. Improper use of pesticides inevitably leads to phytotoxicity. Now let's take a look at the remedial measures after phytotoxicity in fruit trees.
1. Symptoms of phytotoxicity
The symptoms of phytotoxicity differ across different parts of the fruit tree. When phytotoxicity occurs in the buds, they cannot sprout normally, and in severe cases the buds turn black and die. When phytotoxicity occurs in the leaves, within 1-2 days round or irregular red spots appear on the leaf surface, the leaf tips and margins turn brown and dry up, and in severe cases the entire leaf drops off; after 5-7 days, yellowing appears on the leaf surface, and in severe cases the whole leaf changes color and drops off. When phytotoxicity occurs in the fruit, within 3-5 days red or brown spots appear on the fruit, and as the fruit develops these form large patches; after 5-7 days following phytotoxicity, young fruit drops off in large numbers, and in severe cases the entire tree is stripped bare; if phytotoxicity occurs in July-August, rust-colored spots or "flower-face" fruit form, seriously affecting fruit quality. When phytotoxicity occurs in the branches and trunk, the phloem of the trunk turns brown, and in severe cases it extends to the other branches; after 5-7 days the leaves of the whole tree turn yellow and drop or become scorched and dry, and in mild cases some branches die back, while some affected branches recover and grow new leaves.
2. Causes of phytotoxicity
The main causes of phytotoxicity in fruit trees are related to factors such as the quality of the pesticide, the method of application, the fruit tree variety and the climate. Poor pesticide quality, for example expired products, is very likely to cause phytotoxicity. Excessive pesticide use, including too high a concentration or repeated spraying, can very easily cause phytotoxicity. Improper pesticide use, for example mixing two or more pesticides that then react chemically, greatly reduces efficacy and may also cause phytotoxicity. The environment is also one of the important causes of phytotoxicity; for example, after spraying, if the spray solution is not yet dry when rain falls or the temperature is too high, these can all cause phytotoxicity in fruit trees.
3. Remedial measures
If phytotoxicity in fruit trees is discovered early, the plant should be promptly sprayed with water for washing, so as to dilute the pesticide on the leaves and branches and reduce the pesticide content in the tree; the earlier this method is discovered, the better the effect. If the phytotoxicity is caused by soil application, drainage and irrigation washing measures can be used: first flood the orchard with a large or small amount of water to wash away pesticide residues on the ground, then drain promptly. Spraying can also neutralize phytotoxicity; for the phytotoxicity produced by each type of agent, the corresponding relieving substance should be sprayed to neutralize it. For example, for phytotoxicity caused by Bordeaux mixture, a low concentration of lime water can be sprayed to eliminate the toxicity; for phytotoxicity caused by lime sulfur mixture, after washing, a rice vinegar solution can be sprayed to reduce the phytotoxicity. After fruit trees suffer phytotoxicity, fertilizer should be applied promptly to promote recovery of tree vigor. If the phytotoxicity is caused by an acidic agent, plant ash or quicklime can be spread; for phytotoxicity caused by an alkaline agent, ammonium sulfate can be applied; and regardless of which agent caused the phytotoxicity, a mixed solution of 0.3% urea solution plus 0.2% potassium dihydrogen phosphate can be sprayed to reduce the phytotoxicity.
The above is an introduction to the symptoms of phytotoxicity in fruit trees and remedial measures. We hope it helps you. To learn more related knowledge, please stay tuned to us.