Five big truths about pesticides, and after reading this you will understand
Editor's note
Not long ago, an article titled "How Can We Save China Soaked in Pesticides" published by a certain WeChat public account spread widely in WeChat circles. This article caused a strong reaction in the pesticide industry, and people in the industry have said one after another that the article failed to objectively evaluate China's pesticide use situation, was seriously untrue, and had a bad impact on the pesticide industry and agricultural production. The China Crop Protection Industry Association also sent an official letter to that WeChat public account, protesting and calling for not smearing or demonizing pesticides, and for evaluating the merits and faults of pesticides in a scientific spirit and attitude.
Do we really eat so many pesticides every year? Can we do without pesticides? What is the current situation of pesticide residues in China's agricultural products? Let us hear how industry experts forcefully refute untrue rumors and restore the facts.
Rumor
Do we use more than 3 million tons of pesticides every year?
Actual usage is more than 300,000 tons, most of which decomposes in the environment
The article "How Can We Save China Soaked in Pesticides" mentioned: "China's annual pesticide use is 3.37 million tons, and spread across 1.3 billion people, that is 2.59 kg per person." Is the fact really so alarmist?
On this point, Li Zhonghua, secretary-general of the China Crop Protection Industry Association, pointed out that 3.37 million tons is the output data released by the National Bureau of Statistics, of which about 45% is for export, and some is used for forestry, sanitation, public epidemic prevention, rodent control, and so on. According to statistics from the National Agricultural Technology Extension Service Center of the Ministry of Agriculture, China uses more than 300,000 tons of pesticides each year (100% active ingredient), not more than 3 million tons.
Liu Changling, secretary-general of the Pesticide Committee of the Chemical Industry and Engineering Society of China, said that many figures in this article are untrue. For example, a 10% suspension concentrate contains only 10% of the technical material, plus adjuvants and so on, and most of it is water. In addition, directly dividing the total by the total population to obtain an average also does not conform to the facts.
Gu Baogen, deputy director of the Agricultural Product Quality and Safety Center of the Ministry of Agriculture, said that China's actual pesticide use is only more than 300,000 tons. Due to application methods and equipment, the actual utilization rate of pesticides is only 25%-30%, and a considerable part remains on plants or flows into the environment. Pesticides entering the environment will slowly decompose under the action of water, light, microorganisms, and so on. Now the half-life (the time to decompose half) of most pesticides is a few days, and special agents take longer. Now the state will not approve the registration and use of agents with long half-lives. Therefore, although a large amount of pesticides enters the environment after use and pesticide residues exist in the environment, there will not be an accumulation problem.
Rumor
Can we do completely without pesticides?
Crops would be reduced by 35%-40%, and fruits and vegetables would suffer losses of 40%-60%
"Can we do without pesticides?" Many people have similar doubts, so is this idea realistic?
In the "Letter on Explaining the Situation of China's Pesticide Industry" issued by the China Crop Protection Industry Association, it was pointed out that due to improper use or cessation of use, crop yields can be reduced by 35%-40% in that year, among which losses to fruits and vegetables can reach 40%-60%, and in the second year there may even be total crop failure. Pesticides recover for China each year on average 50 million tons of grain, 1.5 million tons of cotton, 15 million tons of vegetables, and 6 million tons of fruits, reducing direct economic losses by more than 100 billion yuan. From the perspective of input and output, for every 1 yuan of pesticides used, 10-20 yuan of direct economic benefit can be obtained.
The National Agricultural Technology Extension Service Center once evaluated the losses caused by rice diseases and insect pests, conducting experiments in the Southwest rice region, Jiangnan rice region, South China rice region, middle and lower Yangtze rice region, and Northeast rice region under seven conditions: complete non-control, farmers' customary control, scientific integrated control, insect control without disease control, disease control without insect control, no control of rice planthoppers, and no control of rice blast. From the experimental results, under the condition of complete non-control, in years with severe outbreaks of diseases and insect pests, the losses caused at the South China and Jiangnan experimental sites were as high as 77.94% and 59.63%, with three-year averages of 64.08% and 50.31% respectively, and the three-year averages in the Southwest, middle and lower Yangtze, and Northeast rice regions were 26.47%, 28.36%, and 19.67% respectively. From these data, it can be seen that without the protection provided by chemical pesticides, our agriculture's food security and grain self-sufficiency would be fundamentally impossible to achieve.
Liu Changling also pointed out that in addition to insect pests, crops are also often infected by diseases. For example, the great famine in Ireland around 1846 was caused by a major outbreak of potato late blight. There are also bitter facts such as rice blast causing total crop failure due to inadequate control. There is also literature research saying that if pesticides are not used, some crops themselves will relatively increase the toxins produced to resist invasion by external diseases and insects, and these toxins such as zearalenone and aflatoxin are known to be carcinogenic. For example, if wheat scab is not controlled with pesticides or is poorly controlled, not only will the yield be low, but eating moldy wheat and its food products will cause poisoning.
Rumor
Is it realistic to rely only on natural enemies to control pests? Chemical control is still the most effective and most economical means
The article "How Can We Save China Soaked in Pesticides" mentioned: "China has more than 1,000 kinds of pesticides, but only more than 20 kinds of pests." However, according to five years of research by the National Agricultural Technology Extension Service Center on the types of harmful organisms of major crops and the characteristics of their occurrence and damage, it was confirmed that China has a total of 3,238 types of harmful organisms, including 599 diseases, 1,929 pests, 644 weeds, and 66 rodent pests.
With so many pests, if as the article mentioned, pesticides are not used and control relies only on natural enemies, is that reliable? Liu Changling pointed out that this statement is absolutely unrealistic. Natural enemies can solve part of the pest problem but cannot solve all pests, and once pests break out massively, relying on natural enemies is of no help.
Li Zhonghua believes that given the current level of development of plant protection science, chemical control is still the most convenient, most stable, fastest, most effective, most reliable, and cheapest control means, especially when sudden or invasive biological disasters occur, and there is still no control method that can replace chemical pesticides.
Gu Baogen said that in order to reduce pesticide use, the state is vigorously promoting integrated crop disease and pest control technology, comprehensively adopting green prevention and control technology, and comprehensively using biological, physical, cultivation, and other measures to control diseases and pests. Apart from local organic agricultural production and a small number of forest disease and pest cases, relying only on natural enemies to control diseases and pests is unrealistic, both in China and abroad.
Rumor
Are pesticides highly toxic?
Highly toxic pesticides account for less than 3%, and pesticide safety is getting higher and higher
"Pesticides are used with increasing toxicity, and pests are controlled more and more." The article "How Can We Save China Soaked in Pesticides" reached such a conclusion. Is this really the case?
"In China, what most people mean by pesticides actually refers to insecticides, especially highly toxic products such as organophosphorus compounds. But the public should also know that pesticides also include fungicides, herbicides, plant growth regulators, and other products. Many pesticide products are now less toxic than table salt." Liu Changling said.
Li Zhonghua introduced that as of 2015, China had banned 33 highly toxic pesticides. China is at the forefront of the world in banning and phasing out highly toxic pesticides, and the number of banned varieties is the largest in the world. At present, the proportion of highly toxic pesticides in China has dropped from about 70% in the 1980s to less than 3% now, so the safety level of pesticide products is getting higher and higher, and there is fundamentally no such thing as "pesticides are used with increasing toxicity."
"With the phasing out of highly toxic pesticides, the toxicity of pesticides in China has dropped substantially. The proportion of highly toxic pesticides is already less than 3%, and low-toxicity and slightly toxic pesticides account for more than 75%. Highly toxic pesticides that once caused a large number of poisonings, such as benzene hexachloride, DDT, and methamidophos, have long been phased out." Gu Baogen said that it should be said that today's pesticides are not what they used to be, and safety is getting higher and higher, which is also why poisoning incidents are becoming fewer and fewer. The overall trend is that pesticide toxicity is decreasing, usage is decreasing, and safety risks are decreasing.
Rumor
Are pesticide residues so terrifying?
Pesticide residues that do not exceed standards are not worth fearing
Pesticide residues are the issue consumers care about most, so how harmful are the pesticide residues on the agricultural products we usually eat?
Liu Changling gave an example, saying that glyphosate is one of the pesticide products with the largest usage. But less than 100 grams of glyphosate is used per mu. Some pesticides use only 1 gram per mu. Even if you ate all the grain or fruits and vegetables from that one mu, how much pesticide would you actually take in? Most pesticides are used at 5-10 grams per mu, and even calculated at 4 applications, it would not exceed 50 grams at most. In short, pesticide residues objectively exist, but whether they are toxic depends on the dose. Today's pesticides, merely by residue alone, will not affect human health.
"One of the main reasons pesticide residues exceed standards is that users do not use them according to the pesticide instructions, that is, they do not consider the pre-harvest interval. For example, if it is stipulated that harvesting can only be done 10 days after application, the applicator instead harvests and sells 3 days after application. At present, most pesticides are applied at mostly 5-10 grams per mu. Even if there are residues, the residue amount is usually measured in ppm or ppb, which is very trace. A document once reported that even if there are pesticide residues, their toxicity is far lower than the toxicity of burnt rice." Liu Changling said.
Gu Baogen pointed out that in rural areas, pesticide applicators are the group whose health is most affected because of direct contact with pesticides. Normal application will not cause poisoning, and most cases of poisoning symptoms occur when necessary safety protection measures are not taken during application. With the continuous phasing out of highly toxic pesticides, the number of actual poisoning cases from application in China is becoming fewer and fewer. Now more than 98% are medium- and low-toxicity pesticides. Unless taken by mistake, the possibility of poisoning or illness is very small.