Control of gibberellin in growing citrus

The citrus bugs occur one generation a year in Chenggu area, and the larvae of different ages spend the winter in the branches of orange trees. The larvae ate into the xylem in late March and began to pupate. The peak period of pupation was in the middle and late April, and the pupal period was about 25 days. The peak period of adult Eclosion is in the first ten days of May and the peak period of adult emergence is in the middle of May. The adults that come out of the hole feed on a small amount of orange leaves to replenish their nutrition, and then mate and lay eggs. A small notch was formed on the edge of the killed orange leaf, but there was little damage to the orange leaf. Adults pretend to be dead and fall to the ground to pretend to be dead as soon as they vibrate. The oviposition period of adults is from late May to early June, and the eggs are mostly laid in the mossy lichens on the branches and under the rough split skin. The eggs are scattered, generally producing only 1-2 eggs in each place, and more than 3-5 eggs, with the phenomenon of overlap. July is the peak period of egg hatching, the larvae after hatching are eaten into the bark for harm, and sputum-like foam appears at the injured place, which is commonly known as "spitting".

Adult stage control: after the emergence of the citrus gibberellin in the xylem of the trunk, it bites through the bark and climbs out (out of the hole) before mating and laying eggs. The Eclosion out of the hole is quite concentrated, and the resistance of the adults just emerging from the hole is relatively weak. seizing this critical period, the adults out of the hole are poisoned, 5% DDT EC is sprayed on the branches, and the spray height is ideal to reach the parts with mossy lichens and warped skin in the branches, which not only saves the cost, but also achieves the control effect of more than 90%. DDT is not only effective in directly killing adults, but also may have a repellent effect on preventing adults from spawning.

Larval stage control: the larva is harmful to the "spitting" phenomenon of sputum-like foam, which is another key period for the prevention and control of gibberellin. Apply 1059 water (1 ∶ 1) and 80% dichlorvos plus water (1 ∶ 3) diluent to the foam, and the control effect is very good. Between the end of June and August, it is found that there are foam holes in the trunk of the orange tree, that is, scrape off the foam and a thin skin (such as the size of a nickel) with a knife, and then apply medicine.

In addition, clearing the garden before April and thoroughly scraping the moss lichen and warped skin from the orange tree can improve the spraying effect of the branches and remove the spawning place of the gibberellin.