Study on the bioecology of alfalfa leaf weevil Hypera postica Gyll. (Coleoptera: Curculionidae) and Its natural enemies populations
Esmaeil Alizadeh, Oruj Valizadegan, Shahram Aramideh, Mohammad Hassan Safaralizadeh and Seyed Ebrahim Sadeghi
Alfalfa leaf weevil (ALW) Hypera postica Gyll. (Coleoptera: Curculionidae) is regarded as one of the most important pests of alfalfa in West Azerbaijan Province, Iran. In order to investigate the population dynamics of the pest, the present study was performed in two regions Saadel (Chaldoran) and Shoat (Maku) during 2014-2015. ALW as well as other insects were collected through regular weekly samplings from alfalfa fields in the regions using nets for catching insects. Based on the behavioral characters of the weevil, 100 net-hits were performed along field diameters in early mornings. The density of the weevil larvae was determined per net-hit. Aspirators were applied to gather mature ALWs from field soil surface. The pest begins its activity in Maku on 4th April and in Chaldoran on 5th May. Its peaks of activity were determined in 19th May and 11th June in Maku and Chaldaran, respectively. The study on the dynamics of the populations of the important parasitoids, Bathyplectes curculionis Thomson, B. anurus Thomson, and Oomyzus (=Tetrasticus) incertus Ratzeburg showed that th most and the least population densities belonged to B. anurus and O. incertus. The population peak of B. curculionis and B. anurus were recorded in Maku at the 15th of May and the 7th July, respectively. In Chaldoran, the population peak of B. curculionis and B. anurus were observed on the 8th June and 6th July. The population densities of the predators in 2014 and 2015 were similar, however, the population density of Coccinella septempunctata was higher than that of Chrysoperla carnea in both regions and years.
Esmaeil Alizadeh, Oruj Valizadegan, Shahram Aramideh, Mohammad Hassan Safaralizadeh, Seyed Ebrahim Sadeghi. Study on the bioecology of alfalfa leaf weevil Hypera postica Gyll. (Coleoptera: Curculionidae) and Its natural enemies populations. J Entomol Zool Stud 2017;5(4):1440-1446.