Occurrence regularity and control of Lagerstroemia speciosa.

Occurrence regularity and control measures:

Occurrence regularity: 1 year has three generations, with nymphs, eggs and pupae wintering in the cracks of branches.

The first generation nymphs began to damage in early April, and the second to third generation nymphs hatched from early June to late June and from mid-August to the end of September.

The peak of insect population is from June to July and from mid-late August to September. Scales reproduce quickly in warm and high humidity environment, and dry heat is unfavorable to their development.

Preventive and control measures:

(1) Combined with plastic pruning in winter, branches with overwintering insects are removed or scraped.

(2) Spraying 3-5 Baume lime-sulfur mixture before germination in early spring to kill overwintering nymphs.

(3) Spraying 2000 times solution of 10% imidacloprid wettable powder or 3000 times solution of 3% hypertonic fenoxycarb emulsifiable concentrate during the incubation period of the nymph.

(4) Protect natural enemies, such as ladybugs, lacewings, aphids, etc.