Abstract:

Involvulus haradai(Kono) adults damage the tender branch tip and young fruit of Canarium album. The experimental results of controlling the weevils by applying 4 strains of Steinernema carpocapsae Bejing、S. feltiae 4、S. longicaudum D43 and Heterorhabditis bacteriophora E-6-7(all as the insectan pathogen), artificially removing the damaged branch tip and using 8 chemical pesticides were studied in this paper. Both strains of S. carpocapsae Bejing and S. feltiae 4 possessed quite high infectivity. When their dosage reached 150 nematodes for one I. haradai larva, the indoor weevil larva mortality rate all reached 100%. The average adjusted mortality rate of S. carpocapsae Beijing was 41.2% and 73.3% respectively with that of S. feltiae 4, 39.2% and 56.2% respectively, when their nematode suspended liquid was sprayed to the projected ground of C. album crown for the forest control according to 200 000 and 400 000 nematode·m^-2 respectively. Artificially removing the damaged branch tip to clear away the insectan origin was practical under 3 m stands and was the most economical and environmentally protective method of controlling the damage to C. album forests and fruit the next year. Among 4 pesticides, the best forest control effect was the 1 000-fold solution of 16% of quinalphos·carbosulfan emulsifiable formulation and its adjusted mortality rate was 66.6%; the second one was the 2 500-fold solution of 2.5% of decamethrin emulsifiable formulation and its adjusted mortality rate was 63.0%; the third one was the 1 500-fold solution of 40% chlorpyrifos emulsifiable formulation and its adjusted mortality rate was 62.0%; and suitable spraying time was Jun.—Sep.

Key words: Involvulus haradai, Insectan pathogenous nematode, Chemical control, Artificial measure, Control effect