Predictive relationship between Spodoptera litura male moths in pheromone trap and their oviposition on cotton.

摘要

In order to determine the relationship between male moth catches and egg masses of Spodoptera litura on cotton foliage, simple correlation and simple linear regression analysis was conducted. The pheromone trap catches of S. litura male moths and egg masses per m2 indicated that the moths attained five peaks (at 30th, 33rd, 36th, 44th, 51st and 28th, 36th, 39th, 43rd, 51st standard week) and three peaks (at 33rd, 36th, 44th and 36th, 39th, 43rd standard week) of egg masses per m2 were observed in cotton crop during 2003-04 and 2004-05, respectively, in Junagadh, Gujarat, India. Further, it is evident from the figures that second to fourth peaks of male moth catches coincided with first to third peaks of S. litura egg masses. There was a decline in S. litura egg masses per m2 on foliage when fifth peak of male moth catches was observed during both years. Correlation analysis between male moth catches through pheromone trap and egg masses of S. litura on cotton foliage revealed that male moth catches had significantly positive relationship with number of egg masses laid during 2003-04 and 2004-05 in cotton. The resultant regression equations indicated that an increase in one male moth catch in pheromone trap caused significant increase in number of egg masses by 0.007 and 0.006 per m2 in cotton, respectively, during 2003-04 and 2004-05. Simple regression analysis showed that male moths contributed approximately 77.8 and 69.1% to the number of egg masses laid during 2003-04 and 2004-05, respectively.