Predator mites (left) are preying on red spiders. (Photo courtesy of Plant Protection and Plant Inspection Station in Wanzhou District)
A sesame-sized beige predatory mite can prey on a red spider that is two or three times larger than itself; a small bag of 1500 predatory mites can make all the pests on a citrus tree disappear...
In 2017, the Wanzhou District Plant Protection and Plant Inspection Station released more than 100,000 bags of predatory mites into more than 12,000 mu of citrus orchards, using predatory mites with "envy and hatred" and a great sense of "justice" to prevent and control citrus full claw mites, archaeopteric mites, red and yellow spiders and other diseases and insect pests, effectively reducing the use of chemical pesticides by about 30%.
"Wanzhou is one of the main citrus producing areas in our city, with more pests and more pesticides applied, which causes certain harm to the environment." Qiao Xinghua, director of the Plant Protection and Plant Inspection Station in Wanzhou District, introduced that the Fifth Environmental Protection Inspection Group of the Central Committee proposed to control agricultural non-point source pollution when giving feedback to the city on April 12, 2017, to this end, Wanzhou District reduced the use of chemical pesticides and protected the safety of the ecological environment by promoting the green prevention and control technology of "insecticide".
If the two problems of wintering and drug resistance are solved
"Insecticide" is achievable
"Killing insects with insects" is easier said than done.
Since 2008, the technicians of the Plant Protection and Plant Inspection Station in Wanzhou District have begun to pilot "insecticide" on citrus trees.
"The predatory mites imported from Guangdong, whose scientific name is Pasteur's Blunt Sui Mite, have experimented with 100 acres of citrus in the agricultural orchard in the western part of Ganning Town in our region." Yan Bangrong, a senior agronomist at the Plant Protection and Plant Inspection Station in Wanzhou District, remembers that many people were skeptical of "killing insects with insects" at that time:
"Can you also use insects to control citrus pests?"
"Can a sesame-sized bug eat a red spider that's the size of a grain of rice?"
What everyone didn't expect was that in a few months, the sesame-sized pasteurized obtuse mite really ate red spiders and other pests that were much larger than itself. But after a winter, not a single pasteur mite on all the citrus trees could be found.
What's going on? After repeated inspection and analysis by Yan Bangrong and his colleagues, they found the reason, "Two factors led to the 'total annihilation of the army' of the Pasteur's blunt mites." "First, pasteurized obtuse mites are a provincial species that do not adapt to chongqing's winter climate and die in large numbers during cooling; second, fruit farmers have also caused a large number of deaths when spraying pesticides on citrus to control insect pests."
Although the first trial was not successful, it gave Yan Bangrong and his colleagues hope, "If the two problems of wintering and drug resistance can be solved, 'insecticide' can be achieved." ”
However, from 2008 to 2012, the trial for 5 consecutive years never solved these two difficult problems.
Promote "insecticide with insects" in 2,000 acres of citrus groves
Pesticide use is reduced by about 1/3
Just when Yan Bangrong and his colleagues were at a loss, in 2013, the Citrus Research Institute of Southwest University cultivated the successfully resistant pasteurized blunt mite on the basis of pasteurized blunt mites, which pushed "insecticide with insects" towards the direction of applied promotion.
"That year, we introduced the resistant pasteurized blunt mites and tested them in 500 acres of citrus orchards in places like the western agricultural orchards." Yan Bangrong introduced that the test results of that year showed that the drug-resistant pasteurized blunt mite has a strong tolerance to general chemical pesticides, and is also more adapted to the climate of Chongqing, and the survival rate in winter is higher.
By 2015, the Plant Protection Plant Inspection Station in Wanzhou District had promoted the application of resistant pasteurized blunt mites in 2,000 acres of citrus orchards, and the effect of "killing insects with insects" was good; in the pilot citrus orchards, the amount of pesticide use was also reduced by about 1/3.
Although the effect of "insecticide" is obvious, the drug-resistant pasteurized blunt mite still has the disadvantages of high natural mortality, low spawning rate and weak diffusion, which has caused certain difficulties in the large-scale promotion of "insecticide".
In more than 12,000 acres of citrus groves
Promote the use of predator mites in more than 100,000 bags
"If bugs can overcome these shortcomings, they can realize the application and promotion of 'insecticide' and effectively reduce environmental pollution caused by the use of chemical pesticides." In the western agricultural orchard, Qiao Xinghua took the Chongqing Daily reporter to look carefully at the citrus tree, "Look, there is one here." ”
Looking down at Qiao Xinghua's fingers, the Chongqing Daily reporter found a bug the size of a sesame seed — it crawled quietly on the trunk of the tree, motionless.
"The predatory mite we are now placing is called 'resistant pasteurized new small mite', which was successfully cultivated in the citrus research institute of the Chinese Academy of Agricultural Sciences in the second half of 2015 on the basis of drug-resistant pasteurized blunt mite." Qiao Xinghua introduced that the natural mortality rate of the drug-resistant pasteurized new small pig mite is low, the spawning rate is high, the diffusion force is strong, and it has strong drug resistance, which is also extremely adaptable to the climate of Chongqing.
These characteristics of the resistant pasteurized new small mite make "insecticide" really have the value of large-scale promotion and application. In 2017 alone, Wanzhou District promoted the use of predator mites in more than 12,000 mu of citrus orchards, producing more than 150 million resistant pasteurized small mites.
At the same time, Wanzhou District has also promoted the use of "insecticide" technology in the cultivation of grapes, tea, strawberries, etc., and has achieved good results.