Abstract:

The eucleid Phlossa jianningana Yang et Jiang is the most important insect pest of Chinese fir tree in South China, infesting leaves only, its injury being severe to the growth of the young trees in recent years. The paper deals with its bionomics and the control measures conducted during 1989-1991 in Fujian Province. Laboratory rearing and field observation showed that this insect has one generation each year in Jianning County, Fujian Province. There are seven larval instars. Overwintering takes place as mature larva (prepupa) within its own cocoon under shallow soil. Overwintering prepupas begin to pupate in early May of the following year. Adults begin to appear in late May, but most of which emerge in mid-June. The eggs are laid in mass on the underside of leaves. The peak period of the fourth instar larvae emerge in mid-August and they begin to cocoon, at maturity, reaching peak in early-September. The two periods are the best period for chemical control. The control methods of the pest are as follows:1.Spraying with 50% Phoxim EC 1000-1500 ×or Beauveria Bassiana Powder to eliminate mature larvae before cocooning into soil.2.Before the fourth instars larvae population reach maximum, it is very effective to spray with Dipterex, Methamidophos, Omethoate, Decamethrin & C.3.Cleaning of fields in early winter to eliminate the overwintering cocoons.4. Establishing mixed stand of Chinese fir, to reduce the infestation obviously.

Key words: Phlossa jianningana Yang et Jiang, Cocooning, Chinese fir