Integrated control of Protapion trifolii (Col.: Apionidae) and its effect on yield component of Berseem clover in Khuzestan province

This experiment was conducted in Safiabad Agricultural Research Center for two years starting from 7th October 2001 in order to evaluate and selection of the best cultural, chemical and integrated control methods of Protapion trifolii (L.) (Col.: Apionidae) in Berseem clover. The effects of control methods were investigated using 9 experimental treatments (including chemical and cultural controls, and the integration of these two methods) in the form of a 2-factor split plot design with 3 replications. Vertical factors were two insecticides, Ecamet and Durseban, and an "untreated" treatment, and horizontal factors were the dates of second mowing (for seed) in 1st, 16th & 31st March 2002. In order to evaluate the amount of damage and the effects of different control methods on yield components, the percentage of inflorescence infestation to larvae before and after spraying, the amount of seed yield, the number of seeds per inflorescence, the number of inflorescences per m2, 1000 seeds weight, the amount of fresh forage, dry forage and the amount of produced protein were recorded. The results of two years combined analysis showed no significant difference among spraying treatments for all the mentioned characteristics, except the percent of larvae infested inflorescences after spraying. Contrary to spraying treatments, there were significant differences among mowing treatments for the percent of larvae infested inflorescences before spraying, the amount of seed yield, the number of inflorescences per m2, the amount of fresh forage, dry forage and the amount of produced protein. Considering the main objective of this experiment (obtaining the highest seed yield) and the high economic value of the clover seeds, the results showed that the mowing date of 16th March 2002 could be suggested as the best date. Also, the chemical control of P. trifolii had no significant effect on seed yield despite its effect on the population of the pest itself, so probably the chemical control of this pest in seed farms of Berseem clover has no economic justification in addition to its harmful environmental effects.