How to identify and control navel orange black bettoria whitefly?
Black whiteflies, also known as orange whiteflies, occur in The navel orange producing areas of China.
(1) Symptoms of harm The black betula mainly harms the navel orange leaves, and the nymphs flock to feed on the back of the leaves. Pale yellow spots appear in the affected areas of the leaves, and the leaves lose their luster and are stunted. At the same time, the insect body excretes honeydew secretions, which is easy to induce coal pollution disease, and the serious damage often causes leaf fall and fruit fall, affecting the tree potential and fruit growth and development.
(2) Living habits The black spiny whitefly occurs in 4 generations per year in the Gannan region of Jiangxi Province, and the generations overlap in the field, and various insect states often appear in the field at the same time. Most of the three-year-old larvae overwinter on the back of the leaves, pupating in March of the following year. The occurrence period of the first to second instar larvae in the field is roughly as follows: the first generation appears from May to June, the second generation appears from the end of June to mid-to-late July, the third generation appears from early August to early October, and the fourth generation appears from mid-October to December. Adults often feather when the dew is not dry in the morning and lay eggs. Black bettorius prefers shade and often lays eggs in dense arcs in the leaf dorsals of the canopy or in the lower middle part, laying several to dozens of eggs at each place, and the hatching nymphs often crawl near the egg shell for about 10 minutes and then fix and feed. The nymph molts the forefoot and leaves the molting shell on the body back. Second- to third-instar nymph camps live permanently.
(3) Prevention and control methods (1) Pharmaceutical control. Spray the first generation of adults in the first generation, or spray the first generation of nymphs in each generation during the peak of the first to second instar nymphs, and spray once every 20 days, and the drug is controlled with the arrow-tipworm. In addition, 90% crystalline dimethods 1,000 times the liquid control effect is also better. (2) Use of natural enemies for prevention and control. Whitefly black wasps, stingray oligodythis, red-spotted lip ladybirds, grasshoppers, yellow aphid wasps and Weberia spores are natural enemies of black betty whiteflies and should be protected and utilized. (3) Agricultural control. Prune insect branches, dry branches and closed branches to reduce the source of insects and improve ventilation and light transmission. How to identify and control navel orange sycamore?