Comprehensive control technology for chive maggot achieves research results
??? Driving through the ten-thousand-mu chive base in Leting Town, Leting County, Hebei Province, the vehicle turned several corners, yet the edge of the base was still nowhere in sight. Inside the bare arched sheds, dark green chives were growing their roots, building up strength for vigorous growth during the peak production season.
At the edge of several chive fields in Xiaozhuang Village, Leting Town, the expert team of the National Public Welfare Industry (Agriculture) Research Special Project "Research and Demonstration of Integrated Control Technology for Crop Root Maggot Pests" was carefully observing the occurrence of chive maggots in the fields. In chive fields of the same variety and adjacent plots, different signs stood upright, each indicating that the plot had used a different technology to monitor and control a pest in the chive fields - the chive maggot.
Chive maggot is the common name for the larvae of the chive gnat (Bradysia odoriphaga). The chive gnat damages more than 30 kinds of vegetables, among which chives suffer the most severe damage, often causing yield losses of 20%-30%, and up to 80% at most. In other words, for chives, encountering an outbreak of chive maggot can mean facing the threat of an almost total crop failure.
"Chive maggots mostly gather in hidden places such as the bulbs and roots of chives to cause damage, resulting in rot of the underground parts and wilting and death of the above-ground clumps." Wei Guoshu, an expert on the project team and a professor at Hebei Agricultural University, bent down, parted a clump of chives, and pointed to a black sticky trap slightly above the ground as he told the reporter.
"Aren't sticky traps usually yellow?" the reporter asked.
"We found that the chive gnat is attracted to black, so we used black sticky traps. Like ordinary yellow boards, they are also coated with glue on both sides." Wei Guoshu explained.
In a chive field with a sign reading "Black Sticky Trap Technology for Monitoring and Trapping Adults," the reporter saw that in a plot of about 4 fen of land, about 6-7 sticky traps stood neatly in a row: perpendicular to the ground, with the short edge touching the ground, facing south to north, all placed at a height of less than about half a meter above the ground. Examining these black sticky traps one by one, the fullest one had already trapped more than 200 adult chive gnats.
"Generally speaking, when we talk about pests, the first thing we think of is often spraying pesticides. For chive maggots, people are mostly accustomed to root drenching to control the larvae, while ignoring the importance of pest monitoring and adult control." Wei Guoshu told the reporter that in the past, researchers were not very clear about the occurrence patterns of chive maggots, such as how many generations occur per year and their overwintering and oversummering conditions, so chive maggot control was highly blind.
Wei Guoshu explained that because chive maggots often cause damage in places such as the bulbs and rhizomes of chives, conducting damage surveys by observing the damage not only makes it difficult to ensure data accuracy, but also causes great damage to the growth of chives.
With the help of black sticky traps, however, it is possible not only to monitor the occurrence patterns of chive maggots, but also to effectively trap adult chive gnats. "Killing one pair of adults can reduce hundreds of larvae." "So we thought of using sticky traps to monitor the number of adults." He told the reporter that through joint research by experts from Hunan University, Hubei Agricultural University, the Hebei Provincial Institute of Plant Protection, and Hebei Agricultural University and other research institutes, the team has basically clarified the occurrence patterns of chive maggots: generally 6 generations occur each year in greenhouses, and 5 generations occur in open-field cultivation, with peak occurrence periods in spring from April to June and in autumn from September to October.
"After clarifying the occurrence patterns of the chive gnat, farmers no longer need to blindly apply pesticides by root drenching." At the project's technical results seminar, Zhang Youjun, a researcher at the Institute of Vegetables and Flowers of the Chinese Academy of Agricultural Sciences, proposed the concept of chive maggot control: "treat summer pests in spring, treat winter pests in autumn" - about 7-10 days after the spring adult peak and about 7 days after the autumn peak, apply pesticides to the soil in time to control the larvae. After harvesting, the chives are tested and found to have no pesticide residues, and applying pesticides at the appropriate time gives very good results.
"One black sticky trap costs about 1.6 yuan, and the investment for a greenhouse is less than 10 yuan, yet such good results can be achieved." Hong Dawei, a master's student at Hebei Agricultural University, has long paid attention to the control of chive diseases and pests, and the effectiveness of the black sticky trap monitoring and trapping technology made him say "I never expected it."
In addition to this small "black board," staff of the Leting County Agriculture and Animal Husbandry Bureau found through research that organic fertilizer made from biogas slurry and biogas residue also has an unexpected effect on chive maggot control. Not far from the demonstration field of "Black Sticky Trap Technology for Monitoring and Trapping Adults" was a demonstration field of "Biogas Slurry Organic Fertilizer Control Technology." No sticky traps were placed in the field, yet the chives also did not suffer obvious chive maggot damage.
Clean energy is one of the five leading agricultural industries in Leting County. In implementing a large-scale straw-based household biogas supply project, the county made organic fertilizer from biogas slurry and biogas residue and applied it in chive fields, and found that the chives grew well, with thick leaves and greatly reduced pest damage.
Li Weibo, deputy director of the Leting County Agriculture and Animal Husbandry Bureau, introduced this technology, called "Improving the Suitable Soil Environment for the Chive Gnat with Biogas Slurry and Biogas Residue," to the reporter: "During the chive production season, apply 2,000 kg of biogas slurry per mu with irrigation water, once every 10 days, twice per crop. This can not only control chive maggot damage, but also improve the quality of the chives, making the taste even better."
"This technology is worth attention and further research. If its mechanism can be clarified, it may promote a new transformation in the rural clean energy industry." said Zhang Guoliang, director of the Energy and Ecology Division of the Department of Science and Technology Education of the Ministry of Agriculture.