Cotton Production in the Presence of Helicoverpa armigera (Hb.) in Central Greece

The present study was conducted in 10 different communities of prefecture of Larissa, one of the main cotton-productive areas of Greece. Monitoring of Helicoverpa armigera lasted four years from 2002 to 2005. The monitoring system included four locations within each community and three traps in each location. Traps were of the funnel type, a reusable injection-moulded kind of plastic trap. Pheromone was z-11-hexadecenyl aldehyde 0.36% w/w. Insecticide (Vapona) was used for all the four years, but for years 2003 and 2004 double traps were used additionally, without the presence of insecticide (only with pheromone). Traps containing a pheromone and an insecticide had significantly greater number of insects trapped than those containing no insecticide. Fluctuation of insect population was different from year to year. Correlations on data between years (insect populations and cotton production across all communities) revealed that, when cotton production was low, the number of adult male insects of H. armigera captured in pheromone traps was high (r = -0.69). There were no statistically significant correlations between cotton production and number of trapped insects when data from all communities (across the four years) were used. Local conditions within each area have been proved important and these results were completely different compared to data concerning specific years. Prediction models must be used for average estimations within great areas that include data from many locations.