Monitoring seasonal population fluctuation of spotted spiny bollworms by synthetic sex pheromones and its relationships to boll infestation in cotton
1991
Qureshi, Z.A. (Atomic Energy Agricultural Research Centre, Tandojam (Pakistan)) | Ahmed, N.
Experiments were conducted to monitor the seasonal population fluctuation of spotted bollworm, Earias vittella (F.) and spiny bollworm, E. insulana (Biosd.) (Lep., Noctuidae) by synthetic sex pheromone traps and relationship between moth catches and larval infestation in bolls of cotton. The traps were baited with 1 mg of sex pheromone (10E,12E)-10,12-hexadecadienal, and 10:2 mixture of (10E,12E)-10,12-hexadecadienal and (Z)-11-hexadecenal for spiny and spotted bollworms respectively. The daily catches of spotted and spiny bollworm moths were variable, however, average catches per night were positively correlated with the larval infestation in cotton bolls. Average nightly number of moths captured in pheromone baited traps was also positively correlated with the number of larvae per plant. The larval population in the fruiting bodies of cotton and the moth counts in pheromone traps increased with the developmental stages of the crop. The peak moth population and larval infestation of spotted and spiny bollworms was observed in the months of August and October respectively. Results indicated that mean trap catches of 9-12 moths per night of spotted bollworm were associated with economic injury level of infestation. Although, a maximum of 12 moths per trap per night in the month of October were captured in case of spiny bollworm but the infestation remained below economic threshold i.e. 10 per cent damage
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