Abstract: This paper is aimed at finding out the relationship between the occure-nce of second generation cotton bollworm and its damage to cotton plants and the tolerance(or compensating ability) of cotton plants through picking bolls off plants artificially as bollworms damage to them. The experiments and demonstrations in 1982-1987 showed that cotton plants at their early stage of reproduction have a marvellous compensating ability when treated with artificial pick-off of bolls and smearing the tops of plants with chemicals. This measure gave the control effectiveness of under 10 boll-worms per 100 plants, yield increase of more than 10%, rotted bolls decrease 50% with the strengthening of the resistance of plants to adverse conditions and delaying the time of emaciation of plants. Meanwhile it reduced costs for control of cotton bollworm and protected natural enemies of the pest.

Key words: Cotton bollworm, Pick-off of bolls, Compensating ability