Influence of Rice Cultivars on the Parasitization Efficiency of Trichogramma chilonis Ishii and Trichogramma japonicum Ashmead

Abstract

Trichogrammatids are efficient egg parasitoids in rice agroecosystem and two species of Trichogramma viz., Trichogramma chilonis Ishii and T. japonicum Ashmead were reported from several species of rice stem borers and other lepiodpterous pests. Physicochemical variations between the cultivars of crops often interfere with the efficiency of the Trichogramma spp. The response of T. chilonis and T. japonicum to the variations in the volatile profile of rice cultivars was investigated. The results indicated that the parasitization efficiency of both T. chilonis and T. japonicum was influenced by the volatiles of rice cultivars. While in some cultivars, such as Kadamba, MTU-1010, KMT 148, KCP-1, the response of T. chilonis was very high, in some of the cultivars like CTH-1, MTU 1010, VTT-5204, the response by T. japonicum was high. The highest overall response of 83.89 % was recorded in the variety Kadamba by T. chilonis. Volatile profile of the cultivars indicated the presence of 9,12,15 octadecatrienoic acid and 9-octadecenal might have played positive role in the attraction of T. chilonis to specific cultivars while hexadecane, heptadecane, petadecane and hexadeconic acid might be responsible for the attraction of T. japonicum