The profile of Spodoptera exigua in the Lepidoptera noctuid family is an intermittent, fulminant leaf-feeding pest in Dafeng City. In 2004, there were major accidents. Nearly half of the cotton fields in the city were affected. The average number of insects in the heavily damaged eastern coastal areas was 150.3. The heavy-damaged fields had only reticular veins and petioles.
Occurrence characteristics
(1) There are many hosts. According to reports, Spodoptera exigua larvae can take 32 kinds of crops. In Dafeng, its larvae mainly harm cotton, cabbage, corn, soybeans, peanuts, and vegetables.
(2) An imbalance occurs. Spodoptera exigua has emergent and the distribution of insects is uneven. According to the survey, the amount of insects in the coastal areas is higher than that in the inland areas. The fields with poor growth are higher than those with good growth, and the areas with high salinity are higher than those with low salinity.
(3) The hazard is long and the generation overlaps seriously. The damage period of Spodoptera exigua in Dafeng is from late May to mid-September and lasts for more than 100 days. In the mid-July to the end of August, where large amounts occur and harms are heavy, all the instar larvae and moths, eggs and cockroaches coexist in the field, and the generation overlaps seriously.
Heavy cause analysis
(1) Facilities The area of ​​vegetables has increased. The development of facility vegetables provided sites for overwintering for Spodoptera exigua, the promotion of light cultivation techniques such as less no-tillage, and the diversification of cropland intercropping methods not only provided abundant food sources for Spodoptera exigua, but also reduced agricultural operations. Control of Spodoptera exigua.
(2) Increased drug resistance. At present, farmers control Spodoptera exigua using pyrethroids or organic phosphorus pesticides, but the test found that these two types of drugs on the control effect of Spodoptera exigua younger larvae is only about 50%, the control effect on older larvae less than 40%, The increase in drug resistance has increased the difficulty of prevention.
(3) High reproduction rate. Spodoptera exigua needs only 28 days to complete a generation in the summer, and it can be destroyed in the short term.
Control methods
(1) Plowing and killing. During the growing season, clean the pastoral, cultivating and weeding, reduce the spawning sites and hosts of Spodoptera exigua, and destroy the insects in the soil.
(2) Artificially catch insects. Using the suspended animation of Spodoptera exigua, either invert the umbrella under the plant or spread the agricultural film on the ground, and then shake the plant, causing its larvae to fall in the umbrella or on the agricultural film and then destroy it.
(3) Chemical control. Spodoptera exigua is highly resistant to pyrethroids and organophosphorus pesticides and the use of these agents has not been effective in controlling Spodoptera exigua. In 2008, we conducted a pharmaceutical screening test. 7 days after the drug, the correct control effect of using 15% of Indomethacin suspension in each mu was 93.4%, and 1% of emamectin benzoate was used per acre. The correction effect of microemulsion 50 ml was 96.6%. In recent years, Dafeng City has promoted the use of these two agents to control Spodoptera exigua in large-scale prevention and control and achieved good control effects.
Drink For Ovarian Health,Red Ginseng Mixed Drink,Healthy Red Ginseng Drink,Double Petal Rose Mixed Drink Nourish
Ningxia Red Power Goji Co., Ltd. , https://www.redpowergoji.com