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As the COVID-19 pandemic spreads around the world, food security is of great concern. Strict prevention of the resurgence of "moths" is a very important task. The device that resembles a street lamp in the field is called a "sexual trapper". As with the beauty scheme, sex attractants continuously release communication signals from female moths, attracting male moths to mate, and then trapping the male moths into traps. This trap can be used for field insect monitoring, and can also trap male moths to reduce mating of female moths in the field. Relying on the research and development results of the institute's technical team, the information released by the sex attractant is highly specific, attracting only the male moth of the grassland moth "into the urn", not other insects, with an accuracy rate of up to 95%.
Text/Guangzhou Daily all-media reporter Long Kun
Photo : Yang Yaoye, all-media reporter of Guangzhou Daily
Development of a sexual attractant to trap the grassland nightcrawler
In The summer of April in Guangzhou is getting stronger, and in a corn field and sugarcane field in Nansha District, there are several "street lamp"-like devices, and Li Jihu, senior agronomist of the Guangdong Institute of Biological Engineering of the Guangdong Academy of Sciences (Guangzhou Sugarcane Sugar Research Institute) (hereinafter referred to as the Institute of Biological Engineering of the Provincial Academy of Sciences), will come to observe the situation of the device from time to time. As a rural science and technology commissioner in Guangzhou, a member of the national sugar industry technology system, and a member of the provincial sugarcane sisal industry technology system innovation team, he is doing demonstration and promotion of efficient green prevention and control technology of grassland moth. This kind of "moth" is known as the "king of crop destruction", and last year it invaded 26 provinces in China, with an area of more than 15 million mu and an actual harm area of 2.46 million mu.
Li Jihu's "Demonstration and Promotion of Green Prevention and Control Technology for Grassland Nightcrawler" was approved this year.
Li Jihu told reporters that in the absence of accurate spraying technical guidance, farmers sprayed a large number of pesticides to prevent and control grassland moths not only increased the cost, but also failed to meet the requirements of the state to reduce the amount of pesticides used, and at the same time had a great impact on the ecological environment of farmland. The grassland moth is relatively mild in the peak period of egg incubation and the larval stage of one to three instars, and is the most sensitive to pesticide resistance, which is the best window period for control. If you seize this opportunity to spray accurately, the effect is good and the dosage is small.
Therefore, at present, Li Jihu promotes the effect of accurate drug use based on accurate detection and reporting of sex attractants, and in addition, cooperates with physical control, biological control and other technical measures for pest control.
In the sugarcane fields and corn fields of the Nansha base of Guangzhou Dongsheng Organic Planting Co., Ltd., they installed sex attractant monitoring equipment.
The device features a thin tubular core that continuously releases pheromones similar to female moths, attracting male moths to mate. Once attracted, the male moth slides into the box inside the equipment. The box opening is small, and the grass moth with extremely weak vision cannot run out at all. Based on the daily statistics of the number of male moths in the trap, the technicians established a mathematical model to predict the occurrence period of the adult grassland moth.
"By predicting the peak period of adult occurrence, combined with the time required from egg hatching to larvae, we can calculate the peak egg incubation period and larval occurrence period to guide farmers to spray pesticides immediately." Li Jihu said that sexual attractants can also be used for the booby trap control of grassland moths. Arranging a certain density of trappers in the field can effectively trap male insects, break the male-female moth sex ratio in the field, reduce the mating rate of female moths, and the eggs laid by unbred female moths will not be able to hatch into larvae, thereby reducing the amount of larvae in the field and achieving the effect of controlling insect pests.
Up to 95% accuracy
Team member Dr. Wu Han told reporters that the compound was infused into the core. Slowly release pheromones externally through capillaries. The compound volatilizes a very small amount per day, only the level of nanogram, which is only equivalent to the use of the "beauty meter" on the grass moth.
"The communication between moths and the same species is very different, and the language of communication between different moths is different. We dig this language out. Wu Han said that the difference between this "language" is the difference between the "quantity" and "quality" of the compound, some moths use different compounds, some moths use the same compound, but the relative proportions between the compounds are different.
The Guangzhou Daily reporter saw at the scene that although it was not the peak of adult insects, there were already several moths lying in the box. But how to release the "beauty plan" and how to ensure that only the grass moth is attracted, and not other insects? Wu Han said that in May last year, they have also been matching the compounds of the lure core, and after screening, the compounds developed can only attract the grass moth, with an accuracy rate of 95%. The lure core that plays a special role will bring a lot of work convenience, and technicians and farmers do not have to do the work of distinguishing when counting the worms in the box.
Background link
Fall Armyworm (FAW), also known as autumn armyworm, is a moth that originated in tropical and subtropical regions of the Americas. It can fly 100 kilometers in one night, and it is difficult to prevent and control.
According to monitoring and analysis, there may be four paths for the grassland nightcrawler to invade China this year, one of which is from the Philippines to Guangdong and Fujian. It can be seen that the direction of the invasion of the grassland night moth is from the south, and Guangdong will be the "first to bear the brunt".
Prevention and control principles
"We predict the larvae by adults, and if there are enough adults in the monitoring equipment, the larvae will appear in the field in three to five days." This time difference can be used to medicate. Gong Hengliang, an expert in pest control in the research team, told reporters that in the early stage of the growth of the grassland night moth, it is also possible to use microbial pesticides to avoid large-scale use of chemical pesticides to reduce the damage to natural enemies of pests. At present, the team member Mao Yongkai is actively carrying out the screening of high-efficiency microbial pesticides.