Control of shell insects in growing peach trees

There are many species of shell insects that harm peach trees. The main occurrence in our province is Korean ball scale, which belongs to Homoptera, Coccidae and Coccidae. When the occurrence amount is large, the damaged branches are covered with numerous shells, so that the tree growth is poor; in serious cases, the leaves and branchlets die, or even the whole plant dies.

1. Occurrence regularity: one generation a year, overwintering as second instar nymphs on branches, starting activity in mid-late March of the following year, peak damage period from late April to early May, Eclosion of males from late April to early May, and mating with females; May females lay eggs under the shell. A female lays more than 700 eggs, sometimes up to 1400-1500 eggs. The eggs began to hatch from the middle to late May, and the peak period was from the end of May to the beginning of June. The hatched nymphs climb out of the mother shell and do harm to the twigs, leaves and fruits, and overwintering begins in September.

Second, drug killing is the main method of prevention and treatment. During the peak incubation period, when a large number of nymphs spread out from the mother shell, spraying 50% marathon 800-1000 times, 40% omethoate 800-1000 times or 80% dichlorvos 1500-2000 times had good results. However, after the nymph spread, it is often difficult to achieve the desired effect. In addition, attention should be paid to the protection and utilization of natural enemies such as black ladybugs.