Cause of pesticide residue
The lack of the basic knowledge of the correct use of pesticides, the vast majority of farmers only use pesticides to prevent and control, the reason is very simple: the effect of insecticide is good, quick effect. There are some farmers do not pay attention to use technology (such as powdery mildew of leaf adaxially, downy leaf on the back, not in the sunny noon Dayao), once that the control effect is poor, will increase the dosage, the pest resistance. When there are insecticide resistant diseases and pests that are harmful to the vegetables in the field, they can be used to prevent and cure them. In such a vicious cycle, the pesticide residues in vegetables will be greatly increased. What is more serious is that some farmers also use banned or restricted pesticides on vegetables. After the use of drugs, the safe interval between pesticides is not yet available, so that it will cause greater harm to the human body.
To understand the use of pollution-free pesticides are not affected vegetable pesticide quality mainly for pesticides, pesticides, pesticides in such in organophosphorus insecticides, namely three 70%: 70% for the use of pesticides insecticide; pesticide 70% for organophosphorus pesticide; organophosphorus insecticides in 70% is high toxic, highly toxic, high residue pesticide. Some farmers believe that the pesticides that are effective immediately after the pesticide are good pesticides, while the low and pollution-free biological pesticides are expensive and slow, which is a waste of manpower and material resources, which also has a certain impact on the quality of vegetables.