Trichogramma yousufi sp. nov. Employed for the Management of Spodoptera exigua and Spodoptera litura in Indonesia

Trichogramma (Hymenoptera: Trichogrammatidae) are minute polyphagous wasps and endoparasitoids of lepidopteran eggs. The objective of this study was to identify Trichogramma species emerging from the eggs of the Asian corn borer, Ostrinia furnacalis (Guenée) (Lepidoptera: Crambidae) attacking corn, Zea mays L. (Poaceae) in Bunga Raya, Siak, Riau, Sumatra, Indonesia, and individuals from an unidentified species obtained from a commercial laboratory in Jatisari, Karawang, West Java, Java, Indonesia. The emergence rate of Trichogramma yousufi sp. nov. Khan & Ikram (Hymenoptera: Trichogrammatidae) on an infestation containing eggs of both pest species, beet armyworm, Spodoptera exigua (Hübner), and the tobacco cutworm, Spodoptera litura (F.) (both Lepidoptera: Noctuidae), on Acacia crassicarpa A. Cunn ex Benth. (Fabaceae) also was evaluated in a nursery in Pangkalan Kerinci, Riau. Two Trichogramma species, namely Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) and a new species, T. yousufi sp. nov., were recovered from the eggs of O. furnacalis in Bunga Raya. Trichogramma poliae Nagaraja (Hymenoptera: Trichogrammatidae) was identified as the species reared in the laboratory in Jatisari. Trichogramma yousufi sp. nov. was compared and separated from its closer species, Trichogramma latipennis Haliday (Hymenoptera: Trichogrammatidae). Trichogramma species, recovered from corn crops and 1 that also was reared in the laboratory, successfully parasitized the eggs of S. exigua and S. litura under controlled conditions. The emergence rate of T. yousufi sp. nov. was recorded at 24.79 to 40.82%, with the highest percentage for more adults of this parasitoid released per m2 in the nursery, indicating its potential to be employed as a biological control agent of Spodoptera in natural conditions.