Tobacco scientific use of pesticides

Pesticides on the development of human civilization, agriculture has played an important role, especially in controlling risk, when the outbreak of pests and diseases, pesticides also show an irreplaceable role. However, in the course of pesticides on the air, soil and water will cause a certain degree of pollution, which requires scientific use of pesticides, with the least amount of the most effective pest control for maximum economic, social, ecological and environmental benefits.

In view of the status of tobacco production, the State Tobacco Monopoly Bureau, Science and Technology Education proposed the development of "pollution-free tobacco" new ideas, backpack weed sprayers relying on science and technology can make use of the use of pesticides near or at the effects of pollution. Despite the development of biological pesticides now in full swing, but it is widely used in the tobacco need to take time.
LD50 (ld50)

LD50 is the result of a biological experiment death of the individual populations of 50% of the dose. According to China Pesticide Toxicology grading standards, rat oral: ld50 <5mg/kg are highly toxic pesticides, such as "aldicarb" original drug ld50 of 1.0mg / kg; ld50 is 5 ~ 50mg/kg is a highly toxic pesticides such as "omethoate" original drug ld50 is 47mg/kg; ld50 of 50 ~ 500mg/kg belong moderately toxic pesticides, such as "fenvalerate" original drug ld50 is 451mg/kg; ld50> 500mg/kg belong toxicity pesticides, such as "In addition to bud through" the original drug ld50 of 1250mg / kg; ld50> 2000mg/kg are practically non toxic pesticides, such as pest control tobacco warehouse "insurable special" original drug ld50 is 34600mg/kg. ld50 reflect pesticides on the environment or the degree of harm to humans and animals by improving the formulation processing technology, can achieve low toxicity of highly toxic pesticides, toxic pesticide poisoning micro. Such as "decis" the active ingredient is "deltamethrin", "deltamethrin" original drug ld50 is 138.7mg/kg, belonging to moderately toxic, processed into 2.5% EC ("decis") After, ld50 is 535mg/kg, belonging to low toxicity pesticides. "Aldicarb" original drug is very poisonous, but commonly used to control aphids Tobacco 15% "iron aldicarb" granules (ld50 is 10.6mg/kg) is highly toxic.

Half-life (dt1 / 2)

Pesticide degradation half-life is a measure of the degree of difficulty of the targets. It reflects the pesticide sustained effect on pest control and pesticide residues levels. agricultural sprayer Long half-life of the pesticide persistence length to pests and diseases, can in a very long time to maintain the role of harmful organisms performance, but it is also the source of pesticide residue formation. dt1 / 2 <3 months of easily degradable pesticides; dt1 / 2 of 3 to 12 months for the middle of pesticide residues; dt1 / 2> 12 months for the long pesticide residues. Early use of arsenic, lead and mercury preparations half-life of 10 to 30 years; half-life of organochlorine pesticides in 2 to 4 years, the half-life of organophosphorus pesticides are generally a few weeks to a few months ("phoxim" The half-life in soil is 34d), carbamate pesticides generally only a half-life of ~ 4 weeks ("aldicarb" In the half-life of fresh tobacco 14.4d), pyrethroids, sprouting products and herbicides half-life of a few days ("deltamethrin" In the half-life of fresh tobacco 2.1 ~ 4.2d; "In addition to bud through" in the half-life of fresh tobacco 2 ~ 4d; Napropamide in the half-life of fresh tobacco 3 ~ 4d).