Evaluation of Affecting Factors in Pheromone Traps Catching for Pomegranate Fruit Moth, Ectomyelois ceratoniae (Lep.: Pyralidae)

The pomegranate fruit moth (PFM), Ectomyelois ceratoniae Zeller (Lep.: Pyralidae), is a polyphagous fruit pest in many tropical and subtropical regions. E. ceratoniae is the major pest of pomegranate orchards in Iran. PFM eggs are laid on or near the calyx, through which second or third instar larvae moving toward the center of it and consuming the interior tissue and seeds of the fruit. It is the most important reduction factor of quantitative and qualitative pomegranate yield in this country and its average damage is about 25%. Synthetic sex pheromone has been widely used for monitoring, timing spray and controlling methods. Insect sex pheromone traps, were used to determine the population density of the pest. In this study, the efficacy of sex pheromone traps, including trap type, height of trap, color of trap, trap situation, dose response, pheromone durability and host effect were studied.
For this purpose, seven series of field experiments were conducted in pomegranate orchards and the factors affecting the efficiency of pheromone traps including trap type and color, the height and situation of the trap, dose response, durability and effectiveness of pheromone trap host, were investigated in Tange-Siab (Koohdasht region) of Lorestan province (longitude 33°23″, latitude 47°12″, height of 856 meters above sea level). The experiments were conducted in a randomized complete block design with four replications, in early August to early September 2010-2011 years. To conduct research, a homogeneous garden (uniform age, variety and gardening conditions) was selected. The distance between the blocks was at least 100 meters. Each week, treatments situation on the block were determined by lottery and then were replaced. Data was analyzed based on a completely block randomized design using SAS software. Mean comparison was done using Duncan's test.
The results showed that, the delta trap was the best type, so it was captured 0.38 PFM moth/day and the tube and funnel traps have the minimum captures (0.13 PFM moth/day). Due to the possibility of passing air through delta traps and increasing the length of the tunnel pheromone, distribution of the pheromone molecules and as a result, insect attraction was more in delta trap compared to the other forms those. The comparison of trap heights showed that, height of 1.5 meter has the maximum capture (0.2 PFM moth/day) and height of 2.5 meter has the minimum capture (0.11 PFM moth/day). This phenomenon may be occured because of increasing altitude in which wind speed increases and pheromone molecules are transferred to further distance and so, moths are more exposed to them. The study on trap color showed that, white color was captured the highest moth (0.28 PFM moth/day) and black cone was captured the lowest moth (0.10 PFM moth/day). The studying on trap situation indicated that, south situation was captured the highest moth (0.25 PFM moth/day) and north one was captured the highest moth (0.12 PFM moth/day). The comparison of dispenser number in trap showed that, two pheremone dispensers trap (0.48 PFM moth /day) and control (0.04 PFM moth/day) treatments had the maximum and minimum captures, respectively. It was also found that the two dispensers in each trap had the best performance in the moth capturing. In other words, with the gradual increase of the pheromone concentration using two dispensers, the more insects were attracted, but less than tow dispensers per trap, the number of trapped moths decreased. The findings about the durability of sex pheromone illustrated that the best time intervals to change the pheromone dispenser are once a week (0.3 PFM moth/day). The results revealed that, changing of dispensers on 7th or 14th days, had the best performance in the moth capture. Also, the results showed that, the trap installation on wooden base was the best choice with capturing of 0.67 PFM (moth/day). It was found that, different kinds of shape and kairomones of the trees were not effective in attracting male insects.
As a result, the most suitable conditions for the usage of synthetic pheromone trap of pomegranate fruit moth, delta-type trap with color white which was set in the pomegranate trees south and 1.5 meter height. Two pheromone dispensers per trap were the best and the best time to replace pheromone dispenser was two weeks. The effect of trap place on the attraction of moth insects showed that trap, set on wooden base, had the highest efficiency.