Flowers are also poisoned by pesticides, and the causes of drug damage are analyzed.

The use of chemical pesticides is an effective method to control flower diseases and insect pests. However, if pesticides are not used properly, it will often lead to drug damage. The main symptoms are uniform spots on the leaf surface, leaf edge curling and scorching, slow plant growth, and even death in serious cases. It is generally believed that the main cause of drug damage is the high concentration of pesticides, and this is only one of the reasons. Sometimes the concentration of pesticides is not high, but it also causes drug damage, mainly for the following reasons:

I. unreasonable mixed use of pesticides

When flower diseases and pests occur at the same time, people usually mix insecticides and fungicides, using two or three agents, and some even add foliar fertilizer. If the properties of several pesticides are the same and the pH values are similar, there will be no chemical reaction and no effect on the efficacy, otherwise it will affect the efficacy and cause drug damage. For example, Bordeaux liquid is a suspension made of copper sulfate, quicklime and water, which can prevent and cure a variety of fungal diseases. Its liquid is alkaline and cannot be mixed with common pesticides, nor can it be mixed with stone sulfur mixture and turpentine agent. Otherwise, it will reduce the efficacy and cause drug damage. Therefore, when pesticides are mixed, we must first understand their pharmacological properties, those that can be mixed, and those that cannot be mixed must be used alone.

Second, the spraying period is too short

In different periods of the occurrence of diseases and insect pests, the cycle length of pesticide spraying is different, generally the initial period is once a half month, and the peak period is once a week. In fact, many pests are difficult to kill and germs are difficult to eradicate. Some flower farmers use drugs frequently, some once every three days, and some even once a day. As a result, the insects are not killed and the disease is not eradicated, but drug damage has occurred in flower seedlings. For this situation, we must strictly grasp the spraying cycle, otherwise drug pests are more difficult to treat than diseases and insect pests. In the prevention and control, we should pay attention to the alternate use of pesticides, in order to prevent pests and bacteria from producing drug resistance, resulting in frequent application, resulting in drug damage.

Third, improper spraying methods

Uneven spraying can also cause drug damage to flowers. When spraying pesticides, some flower farmers do not spray the medicine to the key parts, and sometimes stay in a certain part for too long, which makes a large number of potions stay on the leaves, causing drug damage to flowers, especially on the old leaves and large leaves.

Fourth, the dispensing operation is not standard

There are many dosage forms of chemicals, such as wettable powders, emulsions, tablets, granules, solutions, etc., some of which can be dissolved directly, while others can not be completely dissolved. When the undissolved particles are suspended in the solution, it is very easy to block the nozzle during spraying, and even if the smaller particles are sprayed from the nozzle, they stay on the leaf surface, causing local drug damage to the plant. Therefore, when dispensing, we should pay attention to strictly follow the procedure, dissolve different dosage forms of pesticides in small containers, then transfer them to large containers, and then transfer them to sprayers after they are completely dissolved or dissolved evenly.

There are other pesticide residues in the sprayer

Strictly speaking, different types of pesticides should use different sprayers, but in practice, flower farmers often use some sprayers as general medicine tools, and sometimes use them to treat a certain type of pesticides, and then serve another kind of pesticides without cleaning. as a result, the original pesticide residues are harmful to flowers, especially those such as herbicides, which are more harmful to flowers.

Flowers are allergic to drugs

Practice has proved that some flowers are allergic to certain pesticides, such as cockscomb and rose are quite sensitive to dichlorvos, and chrysanthemums are sensitive to dimethoate EC with a dilution ratio of less than 1500 times. drug damage still occurs in the case of low drug concentration and standard operation. At present, there is no law to follow the allergic phenomenon of flowers to drugs, and it can only be explored through practice. This requires that in the application of unfamiliar pesticides, drug damage experiments should be done first, so as to reduce the occurrence of drug damage.

In short, the occurrence of drug damage is not simply caused by high drug concentration, it is necessary to analyze and find the causes from many aspects, so as to avoid this kind of man-made damage.