Recently, Wang Junxia, deputy director of the plant protection station in Beijing's Changping District, received a call for help from Liu Min, a technician at the Sichuan Vegetable Planting Base. It turned out that a few days ago he found that there were many tiny insects crawling in the flowers of the peppers in the greenhouse, almost every flower had more than ten heads, and there were also small white spots on the leaves, and he was worried about how to control these small insects. Don't underestimate these inconspicuous little bugs, it is one of the four most famous greenhouse pests - thrips.
Thrips are a collective term for the order Lycaenidae. It is small in size, generally 0.5-2 mm in length, and it is difficult to find without careful inspection; The mouthpiece file suction type can file and absorb the young tissues of the plant, causing the plant to grow slowly and fall fruit, which seriously affects the yield and quality of vegetables. In addition to thrips, the four major pests in the greenhouse include aphids, leaf mites and whiteflies. What they all have in common is that they are small sucking pests that suck the sap of the plant by the mouthpart; Small size, fast reproduction; It is highly resistant and difficult to prevent. According to the stubble of vegetables in greenhouses on the outskirts of Beijing, these four pests can occur all year round. After the cultivation of spring stubble vegetables, aphids began to be infested in early April, and leaf mites, thrips and whiteflies occurred from May to June, until another peak of thrips occurred in August and September. Wintering greenhouse lice can overwinter safely, and can also be harmed in December and January; Leaf mites and aphids are the main pests of spring strawberries in February and March. It can be said that these four pests in the greenhouse are "you sing and I appear", and often "perform on the same stage", for the harm ability "no matter what", so that vegetable growers have a headache.
Wang Junxia quickly thought of a way to help Liu Min. It turns out that the Natural Enemy Insect, the East Asian Small Flower Bug, which the Beijing Municipal Plant Protection Station focused on promoting and applying this year, is the nemesis of thrips. Wang Junxia immediately contacted Hou Zhengrong, a senior agronomist in the biological control department of the municipal plant protection station, and they came to Liu Min's pepper shed with the natural enemy product small flower bugs. Hou Zhengrong explained to Liu Min the characteristics and use of the control of East Asian small flower bugs, and then released small flower bugs in the shed according to the dosage of 2 heads per square meter.
1 week later, Wang Junxia and Hou Zhengrong came to Liu Min's pepper shed again, and the thrips on the pepper flowers were significantly reduced, from more than 10 heads 1 week ago to 3 or 4 heads, and the small flower bugs hidden inside could be found by gently flicking the flowers. Small flower bugs can also be seen on some leaves to prey on thrips. Liu Min said happily: "I didn't expect that this little flower bug looked inconspicuous, and it really cured the thrips!" However, he went on to say that the thrips were cured, but there were aphids and cotton bollworms on the peppers at the south end of the shed. Hou Zhengrong told him not to worry, the municipal plant protection station now has natural enemies against these pests, ladybird control can prevent aphids, and red-eyed bees can prevent lepidopteran pests such as cotton bollworms.
In view of the occurrence of these pests, in 2016, the Municipal Plant Protection Station, together with the Plant Protection Plant Inspection Station of Changping District and the Plant Protection Plant Inspection Station of Shunyi District, carried out an experimental demonstration of natural enemy insect --- east Asian small flower bug control and thrips control in 11 bases in Changping District and Shunyi District. In 11 bases, 200 acres of demonstration areas were established, and a total of 100,000 East Asian small flower bugs, 1.5 million red-eyed bees, 10,000 ladybugs and 5,000 smoke blind bugs were released. In the demonstration shed, the "integrated natural enemy control" strategy was adopted, and other pests other than thrips such as aphids, whiteflies, leaf mites and lepidoptera pests were used to release pests in the control shed by single or combined natural enemies, such as East Asian small flower bugs + smoke blind bugs for the control of thrips and whiteflies, East Asian small flower aphids + ladybirds + red-eyed bees to control thrips, aphids and twill moths. The municipal plant protection station communicates the occurrence of pests with the demonstration area and county in a timely manner, and coordinates the natural enemy manufacturers to supply natural enemy products in a timely manner. The municipal and district plant protection stations jointly used centralized training and field guidance to explain the principles and application technologies of natural enemy prevention and control to farmers and base production personnel, which was welcomed by the base and farmers.
With the continuous improvement of the concept of agricultural product safety, more and more professional vegetable growing institutions and farmers dedicated to growing green and organic vegetables have emerged in the suburbs of Beijing. In the face of the problem of vegetable disease and pest control, we are more and more inclined to adopt more environmentally friendly and effective control methods, biological control represented by natural enemy insects will undoubtedly become an effective way for the healthy development of agriculture, and small natural enemy insects will play a greater role in the future.
(Beijing Plant Protection Station, Hou Zhengrong, Li Jinping)
Figures:
Fig. 1 East Asian flower bugs
Fig. 2 Ladybird larvae prey on aphids
Fig. 3 Predatory mites prey on leaf mites
Figure 4 Smoke blind bugs prey on whiteflies
Figure 5 Investigation of the effectiveness of natural enemy prevention and control