Study of population fluctuations of Codling moth, Cydia pomonella (Lepidoptera: Tortricidae) in apple orchards of Kohsorkh region

Cydia pomonella is one of the most important pests of apple orchards in Iran and the world. Its damage to apples is of considerable economic importance, as it reduces the quantity and quality of fruits. The larvae of this insect do the most harm, and the larvae eat mostly on apple seeds, but it also feeds on apple flesh tissue until it reaches the seeds. Sex pheromone plays an important role in tracking and controlling this pest, so using pheromone traps to get the best spraying time and prevent indiscriminate spraying is inevitable.

In this study, the population changes and determining the peak time of flight in different generations of Cydia pomonella in the gardens of Kohsorkh region of Khorasan Razavi province were investigated. As a result, four pheromone traps were set up in the region's apple orchards in 2018, and the number of insects caught in the traps was counted at regular intervals.

 According to the observations, the time of the emergence of adult insects of this pest was in the first decade of May, and their flight continued until the first decade of October. The apple worm moth had four peak flight points. Studies conducted in this study showed the existence of four generations for this pest in the Kohsorkh region.

Two damaging generations of codling moth is recognized, one in late spring (after petal fall) and the other in midsummer. Feeding by the larvae of the latter causes most fruit damage. Using pheromone traps containing the sex attractant of the female moth can improve treatment timing. Insecticides are most effective when administered 10 to 14 days after peak flights are identified in pheromone traps using this method. The findings of this research revealed the four peaks of complete insect flying. The first flight peak emerged on 17 May, followed by a sharp decrease to the second flight peak on 14 June. After this peak, in terms of warmer weather, the activity of the pest was reduced. The trap hunting process decreased, and in the period from June 20 to July 14, it remained unchanged and reached zero. The third happened; then, the hunting continued with fluctuations and finally on September 8, the fourth peak of the flight was observed. After the last peak, regarding the gradual decrease of temperature and lowering of the average temperature from the minimum thermal threshold, the flight activity of moths decreased and from 10 October onwards, the trap hunting stopped. The third and fourth generations had the highest hunting rate and the first and second generations had the lowest hunting rate.