Laboratory Bioassays, Grasshopper Control, 1975-76

Test 1 - Encapsulated Sumithion was tested against nymphs from eggs harvested from field-collected adults; the nymphs were reared in the laboratory on a diet of Balbo rye seedlings and wheat bran. Four concentrations (from approximately 10-40 μg ai/g of body weight) of each formulation were tested both topically and orally with ten 5th-instar M. sanguinipes per replicate. Topical treatment: A microapplicator was used to apply a 1-ul droplet to test insects. The droplets of TD-2010 and TD-2011 in water were applied under the inner wing pad so the material would adhere to grasshopper until the water evaporated. The standard EC formulation of Sumithion was mixed with acetone, and the droplets were applied to the dorsal surface of the third or fourth abdominal segment. All treatments were replicated four times.