Abstract: A comparison of moth catches of the cotton bollworm,Helicoverpa armigera (Hübner),in water tray traps(20～30×7～10cm) baited with synthetic sex pheromone vs blacklight traps (20w) was made at 3 locations in Shandong and Anhui Provinces,China in 1993 and 1996.The results show that male catches per trap per night in water traps were 4.18 and 2.49 times as many as that in blacklight traps at location 1 and 2,respectively Both the differences were statistically significant ( P< 0.05)However,at location 3 the mean catches in water traps were only 56% of that in blacklight traps but the difference was not significant ( P < 0.40)It is seemed that the catching efficiency of water traps decreased with season and might be lower than that of blacklight traps in August and SeptemberTherefore it is generally suitable to use the pheromone traps for monitoring of the bollworm population dynamics,especially during the overwintered and 1st generations (commonly during late April to early July in most China′s cotton areas)

Key words: soil salt content reduction, cotton, compensation effect.