Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae): a potential biocontrol agent of rice leaf folder

Abstract

Rice leaf folder, Cnaphalocrocis medinalis is a major pest, in many rice growing areas of Sri Lanka. Biological control of this pest is encouraged due to ill effects of insecticide application on rice ecosystem. Use of egg parasitoids is advantageous over larval and pupal parasitoids, as they could destroy pests at the egg stage. Trichogrammatoidea bactrae present in rice fields in Sri Lanka, is an egg parasitoid of rice leaf folder. This study was conducted to assess the potential of T. bactrae as a biocontrol agent for the management of rice leaf folder. T. bactrae was reared on Cocyra cephalonica and its fecundity, longevity and parasitism were assessed. Acceptance of stored host eggs and parasitoid emergence from stored parasitized eggs were examined. Dispersal ability of parasitoid was also examined. T. bactrae adults showed a mean longevity of 7.9 days (range 1-15 days) and laid 55 eggs / female during first 5 days; of which, 56 % of eggs was laid on the first day. There was a significant reduction (F=5.26; df=14; 89; P< 0.001) in parasitism, 66-35 %, with increasing number of generations on C. cephalonica. Parasitism steadily decreased as the number of generations increased. Acceptance of C. cephalonica eggs varied significantly with temperature (F=187 df=1; 126 P<0.001). Mean acceptance at 4 and 8 ºC was 30 and 42 % respectively. Acceptance also significantly varied with the duration stored (F=385; df=6; 126; P<0.001). Parasitized eggs of T. bactrae could be successfully stored under low temperature (4 ºC) up to 40 d. Over 80 % parasitism was achieved with 150 parasitoids released within 25 cm radius circle. Hence, T. bactrae is a promising candidate to be promoted as a biocontrol agent of C. medinalis.

Kairomones effect on parasitic activity of Trichogramma japonicum against rice yellow stem borer, Scirpophaga incertulas

“…Biological control of insect pests using egg parasitoids includes over 11 taxonomic orders (Vinson, 1976). Employing release of egg parasitoids within the genus, Trichogramma has been successfully demonstrated worldwide and advocated to be an alternative to chemical insecticides in many crops (Ko et al, 2014; Perera, Hemachandra, & Sirisena, 2015; Senthil‐Nathan, Kalaivani, Mankin, & Murugan, 2006; Tang et al, 2017). Trichogramma japonicum has been recommended as an effective species for lepidopteran pest which are laying eggs in mass, as this species has comparatively long ovipositor to parasitize eggs in deep layer (Hou, Wang, Zhang, & Wan, 2006; Yunus, 2018).…”

Short-term storage of the egg parasitoids, Trichogramma and Trichogrammatoidea

“…Trichogramma cordubensis Vargas and Carbellois is an exotic species, which is used world-wide to control Autographa gamma (L.), Chrysodeixis chalcites (Esper), Phlogophora meticulosa (L.), Peridroma saucia (Hübner), Xestia c-nigrum (L.), and Noctua pronuba (L.) (Garcia et al 1995;Lingappa and Hegde 2001;Singh et al 2001;Lalitha and Ballal 2015). Trichogrammatoidea bactrae Nagaraja was tested against rice leaf folder, Cnaphalocrocis medinalis, and emerged out to be a highly promising bioagent (Perera et al 2015). In India, T. chilonis is considered as the most promising indigenous species which has a wider host range and high survival capacity.…”