Effectiveness of Trichogrammajaponicum utilization for biological control agents on Scirpophaga incertulas in Indonesia

Abstract

Background and Objective: One of the Trichogramma species commonly used to control rice stem borer is Trichogrammajaponicum [T japonicum). The following research aimed to (1) Investigate the effect of the age of the parasitoid and the age of the host egg on T japonicum's parasitization ability and (2) Know the pattern of dispersal and the effect of the release of T. japonicum against the intensity of parasitization. Materials and Methods: The testing method used was a factorial experiment with a completely randomized design. The first factor consisted of five different life stages of parasitoids (UP), delineated from 0 up to 4 days (UP-0, UP-1,UP-2, UP-3 and UP-4). The second factor in this experiment consisted of the 5 life stages of the host egg (Ul), which were the ages of the host eggs from 0-4 days (UI-0, UI-1, UI-2, UI-3 and UI-4). Twenty-five units were treated at a time and the treatment process itself was repeated 5 times so that the whole experiment used 125 units in total. The data were analyzed using one-way (ANOVA) and significant effect continued with Tukey HSD test (p < 0.05). Results: One day old T japonicum parasitoid was more effective biocontrol agent compared with older parasitoids. Levels of parasitization were highest upon available host eggs less than 24 h old. Trichogramma japonicum in the field can be scattered in all directions and can reach a distance of up to 6 m (36 m2) within 7 h. The existence of T. japonicum in the field proved to successfully control the population of Scirpophaga incertulas, if the population of S. incertulas eggs in field was low, the population of the parasitoid was similarly reduced. A dosage of 250,000 released parasitoids ha-1 was more effective than a 125,000 dosage of parasitoids ha-1 Conclusion: An increased dosage could increase the intensity of parasitization by 236% when compared to controls. This research also encountered Telenomusrowani and Tetrastichus schoenobii in the field and they also attacked S. incertulas eggs.