Seasonal incidence of hymenopteran parasitoids of Henosepilachna spp
Muntaha Qamar, Masarrat Haseeb and Uzma Manzoor
Studies on population dynamics of two hymenopteran parasitoids (i.e. Pediobius foveolatus (Crawford) and Tetrastichus sp. (Hymenoptera: Eulophidae) of Henosepilachna spp.were carried out for two successive years (2015 and 2016) on various crops viz., brinjal, bitter guard, tomato and winter cherry, in an experimental field of Department of Plant Protection, Aligarh Muslim University, Aligarh, India. Observations were taken on 4 randomly selected plants from each plot by collecting various developmental stages (i.e. eggs, grubs, pupae and adults) of Henosepilachna spp.These developmental stages were brought to the laboratory and continuously kept under watch for the emergence of any parasitoids from parasitized hosts. After emergence of parasitoid from parasitized stages of Henosepilachna spp., they were collected in glass vials separately and samples were identified by the experts. Results of the study showed that temperature range of 29.10 to 31.81 ºC, relative humidity between 61.86 to 85.07% and rainfall between 0 to 50.80mm, favoured the population of P. foveolatus and Tetrastichus sp. to maximize the percentage of grub parasitization of Henosepilachna spp. on all tested host plants. From the present study, it can be concluded that the sufficient knowledge of biotic and abiotic factors affecting the seasonal incidence of natural enemies of pest is an important part of Integrated Pest Management (IPM) program, which helps growers/farmers to check the population of pests at below economic threshold level by using natural enemies as a mean of pest control tactics, thereby reducing the use of synthetic pesticides.