Prevention of cabbage caterpillars
The larvae bite on the host leaves. Before the 2nd instar, they only eat the leaves and leaves a transparent epidermis. After the 3rd instar, the larvae encroach on the holes or nicks of the leaves. When the larvae are severe, all the leaves are eaten, and only the rough veins and petioles remain. Caused the popularity of soft rot of cabbage. When the cabbage caterpillar feeds, it will pollute the feces while feeding. The larvae were 5th instar, and they were mostly damaged in the leaves before they were 3rd instar. After 3rd instar, they turned to foliar nibbles. The feed intake of 4-5 instar larvae accounted for 97% of the total larval feeding intake.
Second, living habits and the law of occurrence
The cabbage caterpillars occur in Shandong for 5-6 generations each year. Overwintering adults occur in March. The most serious damage is from late May to June. Due to high temperatures and rainy days, the number of natural enemies increases and the host lacks, resulting in a significant reduction in the number of populations. As of September, the number of insect populations has risen to form the second peak of damage. Adults are active during the day and live the most at noon on sunny days, with a lifespan of 2-5 weeks. Spawning has strong tropism for cruciferous vegetables, especially for thick leafy cabbage and broccoli with a large amount of eggs, which is produced on the back of leaves in summer and on the front of leaves in winter. Oviparous spawning, larvae sluggish, not lively, more mature after climbing to high drought is not easy to submerge place phlegm, non-overwintering is often planted in the back of the bottom leaf blade planthopper petal. And spinning silk entangled the body on the attachment.
Third, prevention and control measures
In recent years, the damage of Pieris rapae has been serious. In the course of chemical control, resistance to the drug has rapidly developed, resulting in difficulty in controlling Pieris rapae. The focus of its prevention and treatment is timely prevention and control, and alternate medication. Specific prevention methods are as follows.
1. Agricultural control After the harvest of clean garden cruciferous vegetables, the old leaves of the field stubs are promptly removed, the breeding sites of cabbage caterpillars are reduced, and part of the earthworms are eliminated.
2. Chemical control generally takes about 1 week after the peak of the egg, ie, the larvae hatches to the 3rd instar larvae and uses 2-3 times continuously. The following agents can be used:
(1) 2% vegetable and insecticide acaricide 30-50 g / 667 square meters, watered 50 kg or high efficiency Bt WP 750-1000 times, can also be used 0.2% ave bug clear oil 2500-3000 times spray Treatment, these three pesticides are bio-insecticides, the effect is good, not easy to produce drug resistance, pollution-free, can be used continuously.
(2) 10% to quench emulsion 5-10ml/667 square meters, 10% dilute the suspension agent 10ml/667 square meters, 5% kungfu inulin emulsifiable concentrate and 5% lefluxin emulsifiable concentrate 2000-3000 times or other chrysanthemum vinegar Emulsion spray treatment.
(3) 20% Diflubenzuron No. 1 suspension agent and 25% Diflubenzuron No. 3 suspension agent 1000 times spray treatment should pay attention to seize the appropriate control period, in the field of eggs, the early stage of larval hatching spraying, according to The habits of cabbage caterpillars are sprayed evenly on the back of the plant leaves in the morning or evening, which can effectively prevent the damage of cabbage caterpillars.
Small Volume Injections,Small Volume Sodium Chloride Injection,Potassium Chloride Injection,Small Volume Glucose/Dextrose Injection
Shandong Qidu Pharmaceutical Co., Ltd. , https://www.qdyypharma.com