Telenomus remus Nixon

Telenomus remus has been reared from the eggs of Spodoptera mauritia Boisduval in Malaya and described by Nixon in 1937. It is an important egg parasitoid in Fiji. In India this species of egg parasitoid has been introduced from New Guinea through CIBC for evaluation against Spodoptera litura (Fabricius) and Achaea janata (Linnaeus). Although exotic, its inundative release has been suggested for protection of cauliflower and tobacco in Gujarat and Andhra Pradesh, respectively. At NBAII, cauliflower, beetroot, okra, castor and cabbage are the preferred plant host in that order on which T. remus could efficiently parasitise S. litura eggs.

Telenomus remus is primarily produced on the eggs of tobacco caterpillar, S. litura, which is the preferred host. It could also parasitise S. exigua (Hübner), Helicoverpa armigera (Hübner), Plusia signata Fabricius, Agrotis segetum Denis and Schiffermuller, Agrotis biconica Kollar, Agrotis ipsilon (Hufnagel), Mythimna loreyi (Duponchel), Trichoplusia ni (Hübner), Achaea janata (Linnaeus) and Corcyra cephalonica etc. The production procedure for S. litura has already been given. Out of the total production and of eggs for this unit 90% are utilized for T. remus production, the rest for continuation of host culture. The ideal conditions for rearing of T.remus are 27.5°C and 75.5 % relative humidity.

T. remus males have filiform antennae and short abdomen whereas females have clubbed antennae and longer and wider abdomen with the ovipositor clearly visible under 10X hand lens. The males emerge before females, the adults are paired for 24 hrs for mating after which the males die and after this preoviposition period, the adults females are confined in 15 x 2.5 cm glass tubes. A small piece of cotton swab soaked with 5% honey solution is stuck on the side of the glass tube for feeding the parasitoids. 6000 freshly laid (0-24 hrs old) S. litura eggs are stuck on a 10 x 2 cm gummed thick paper piece and exposed to 100 parasitoids for 24 hrs for parasitisation. The exposure could be continued for 2 days, on third and fourth day only 3,000 eggs may be provided and on 5th day only 1500 may be provided. Most of the parasitized eggs turn black in 4 to 5 days. The larvae hatching from unparasitised eggs are removed from the card. The cards carrying only parasitized eggs are transferred in the fresh clean tubes for emergence of the parasitoids. The adult parasitoids emerge in 9 to 10 days and the parasitoids emerged could be used for field releases by retaining 10% for continuation of the cultures.