Whitefly, commonly known as the white moth, or simply called whitefly, is an important pest for many crops such as vegetables and flowers. With the development of the cultivation of vegetables, greenhouses, and plastic greenhouses, the occurrence and damage of whiteflies has been increasing year by year, resulting in reduced production of vegetables. The worm has a wide host range and is difficult to control. Now with the cultivation practices, the characteristics and main biological control methods are described as follows: First, how to identify whitefly 1. Morphology Whitefly parasites and wings are white. Body length 1--1.5mm, wing surface covered with white wax powder, when the rest of the wings synthesis such as moths. The egg is about 0.2mm long, and it is pale green at first, coated with wax powder, then has a brownish color and is black before hatching. Nymphs are pale green or green and live close to the leaves. 2. In the event of damage, the whitefly pollinated adults and nymphs clustered on the backsucking plants. It sucks the mouthparts into the leaves and sucks the sap. The damaged leaves turn green, yellow, wilting, and even the whole plant withers. At the same time, the adult can secrete a lot of honeydew, grow black coal-borne pathogens, and cause coal pollution. Adults tend to have tenderness. Before the host plant topping, adults always chase the top leaves as they grow. The top-down distribution on the crop is: Newly produced green eggs, darkened eggs , nymphs of old age, nymphs of old age, false nymphs, new adult nymphs. Therefore, different leaf positions can see different insect states. Insects often occur at the same time, which brings difficulties to biological control. Second, biological control methods Artificial release of citrifolia wasp to control whiteflies. In 1978, China introduced cicade bees from the United Kingdom to conduct a large number of trials to control whitefly, and achieved good control and prevention effects. The parasitoid and nymph parasitized by the parasitoid, usually in the greenhouse, can survive for 10–15 days. The spawning females probe the whitefly nymphs with tentacles and then penetrate the ovipositors to test whether the eggs in the whiteflies have the eggs. Adult bees prefer to choose the third-instar nymphal stage and the fourth-instar stage of pre-albumenia. The adult bees can also probe the whitefly nymph and take the body fluid of the whitefly. The whitefly died after being probed. Each female bee can lay 50--100 eggs and up to 350 cans. After parasitism, the whitefly's nymphs and cockroaches turn black. In addition to the effect of the age of whitefly on parasitic effects, the temperature, humidity, and light intensity of the greenhouse can also affect the parasitic effects. Under the low temperature of 18°C, the reproduction rate of whitefly is 9 times larger than that of the parasitoids. The amount of parasitic wasps required for prevention and control can be well controlled. At a high temperature of 26°C, parasitoids develop twice as fast as white flies, and the amount of parasitoids can be appropriately reduced. In general, when each plant has 0.5--1 whitefly, each bee is given 3- or 5-heads, placed 1 or 10 days apart, and the bees are placed 3- or 4 times in a row to control them. Harm. Beijing Academy of Agriculture and Forestry Sciences, plant protection and environmental protection research All the products of the Lishui wasp are sold and can be used for mail order business. Mailed out is a whitefly that has been parasitized by the citrifolia bees. The specific application can be used to directly release the black cockroach, and it can also be released after the larvae have emerged. 2. Prevention of Greenhouse Whitefloat with Chinese herbicides in the greenhouse The most common species in China is widespread, with multiple generations occurring in one year and overlapping generations. In the Guangzhou area 1 year up to 7-8 generations. In addition to feeding whitefly in the greenhouse, Chinese wormwood can also be used as a vegetable meal. However, there are currently no commercial insects for sale, and it is generally necessary to collect and expand them on their own. The artificial breeding techniques of Chinese grasshoppers are relatively mature, and reference can be made to relevant literature, such as "Chinese biological control". 3. Use of 0.3% Azadirachtin Emulsion 1000 times to control whitefly Azadirachtin is a botanical insecticide extracted from Neem tree. It is safe to humans, livestock, birds and bees, and is very easy in the environment. Degradation is currently an important type of plant-derived biological pesticide. Its mechanism of action is that the insect has a strong antifeedant, repellent and inhibit growth and reproduction. Lepidoptera pests are reported to be sensitive to it. In September 2002, a trial of azadirachtin used to control cucumber mealworms was conducted on a greenhouse cucumber at the Zhuhai Research Center for Agricultural Sciences. Combined with agricultural control and physical control measures, the comprehensive control effect was 89.51. %. 4. Pharmacy-assisted prevention, attention to accurate medication, and early prevention and treatment. You can use the yellow board to monitor the time of drug use. After the trial application, the spraying of 10% imidacloprid wettable powder 1500 times and the enemy-dead insect (mineral oil) 200 times is ideal when the whitefly occurs sporadically. Efforts should be made to make the spray even when it is sprayed, so that the medicine can fully penetrate the leaves, especially the back of the leaves. If the control is based on chemical agents, pay attention to rotation and alternation of medication, and strictly control the amount of medication so as to avoid pest resistance. In addition, due to the rapid reproduction of whiteflies and their ease of propagation, production units within a region should pay attention to joint prevention and treatment to increase overall control effectiveness.
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