Alteration of effectiveness of Steinernema carpocapsae weiser (steinernematidae: rhabditida) against Spodoptera Litura (F.) (Noctuidae: Lepidoptera) larvae on sunflower by addition of an insect phagostimulant

Addition of an insect phagostimulant (PS) ‘Entice’ to nematode suspension at 0.032% in addiion to the antidessicant glycerine 0.1% and the surfactant ‘Triton’ 0.05% enhanced the effectiveness of Steinernema carpocapsae (Strain DD-136) against the fourth-instar larvae of Spodoptera litura feeding onsunflower heads, in laboratory and field tests. The nematode-infected insect larvae showed suppressed feeding activity, which was enhanced and brought about to near normalacy by PS. The addiion of PS increased the rate of insect mortality especially at lower nematode doses. In field trial foliar application of 2 x 10⁶ IJ/ha in 5001 of water suspension, exclusively to flowerheads (−approximately 500 lJ/flowerhead), with a high volume sprayer gave an insect kill of 21.7% and 11.7% with and without the addiion of PS, respectively.