Potato ladybug prevention method
First, the damage of potato ladybugs
Potato ladybirds are mainly harmful to solanaceous plants and are important pests for potatoes and eggplants. Both adults and larvae feed on the same plants. After eating, leaves remain on the epidermis and many parallel tooth marks are formed. The leaves can also be eaten as holes or only veins. In severe cases, the whole field is as coking and the plants die and die.
Injury characteristics Adult nymphs, nymphs feeding on leaves, fruits and tender stems. The damaged leaves retain only the veins and the epidermis, forming a number of irregular transparent veins, and later become brown spots. Excessive leaves will cause the leaves to wither. On the victim's fruit, it is licked into many concave patterns, gradually hardens, and has a bitter taste and loses its value.
Second, the potato morphological characteristics
Adults: body length 7 ~ 8mm, hemispherical, auburn, dense velvet yellow hair. The front edge of the thoracodorsal plate is recessed and the leading edge is prominent. There is a large sword-shaped marking in the center and two black spots on each side (sometimes combined). There are 14 dark spots on each of the two elytra wings, and the four dark spots behind the three dark spots at the base of the eel are not on a straight line. There are 1 to 2 pairs of black spots at the joints of the two sheath wings. Eggs: 1.4mm long, vertical, bright yellow, vertical stripes. Larvae: body length of about 9mm, pale yellow-brown, oval-shaped, the back of the bulge, each section with black sticks.蛹: about 6mm long, oval, light yellow, sparsely fine hair and black markings on the back. The end of the larvae wraps around the skin.
Third, the living habits of potato ladybugs
In Gansu and Sichuan, east of China, it occurs north of the Yangtze River basin. For most of the northern part of the region 2-3 generations in one year, the adults clustered for winter. It is generally started in May and is harmful to potatoes, tomato and green pepper seedlings in potatoes or seedbeds. The first half of June is the peak of spawning, and the period from late June to early July is the first generation of larval infestation, and the middle and late July is the peak period of phlegm, and the end of July and early August is the first generation of adult emergence, August. In the middle of the year, the second-generation larvae were destroyed. In late August, larvae began to phlegm. The eclosion adults began seeking wintering sites in mid-September and began wintering in early October. Adults are most active from 10 a.m. to 4 p.m., mostly feeding on the back of a leaf before noon and turning to foliar feeding after 4 p.m. Adults and larvae have the habit of eating the same eggs. Adults are more likely to die, and secrete yellow mucus. Overwintering adults spawn more eggs in the base of the potato seedlings, and 20-30 capsules are close together. The larvae have a total of 4 instars after hatching at night. After the larvae are mature, they are mostly on the stems or leaves of the plants.
Fourth, potato ladybug prevention method
1 It advocates the use of insect nets for the prevention and control of eight-star ladybugs, as well as other pests.
2 Manually capture adults. Using the adult dead habits, the pots were used to take and beat the plants to make them fall, and they were collected and destroyed.
3 Manually remove the egg mass. The insects spawn in groups and have bright colors that are easy to find and easy to remove.
4 Use Bacillus thuringiensis "7216" to prevent potato ladybugs. The “7216†inoculum powder contained 10 billion g/g of spores, 10 kg per 667 square meters, and was sprinkled on the dew plants before eggplant, ladybugs and beans. The control effect was 37.5%. ~100% or spray 2.0% rotenone EC 1000 times.
5 Chemical control: To seize the favorable opportunity before the larvae are dispersed, spray 25% thiamethoxam water dispersible granules 4000 times or 20% fenvalerate EC 3000 times or 2.5% deltamethrin EC 3000 times, 80% dichlorvos 1500 times, 50% phoxim 1000 times, 2.5% lambda-cyhalothrin 2000 times, 90% crystal trichlorfon or 50% malathion 1000 times, 2.5 % of deltamethrin EC or 20% fenvalerate or 40% chrysanthemum or chrysanthemum EC 3000 times, 21% chlorimuron EC 6,000 times, 2.5% VS 5000X.
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