Control of the Sweetpotato Whitefly in Cantaloupe in Texas, 1991

Cantaloupe was seeded into Sunshine Mix* potting mixture in 10 cm pots on 19 Mar in a greenhouse heavily infested with SPW. Plants were transferred on 8 Apr into spray chambers (25 cm X 30 cm PVC cylinders) in a randomized complete block design with ten treatments and six replicates. Plants were irrigated daily using drip tubes to avoid wetting of foliage. Untreated plants were interspaced between treated plants for an added source of SPW adults. Adults were counted on the third expanded leaf from the growing point and SPW immatures were sampled using a 2.1 cm diameter leaf disk cutter 24 hours prior to treatment. Plants were sprayed to runoff (3 seconds/31 ml/plant, ca. 100 gal/acre) using a C02 backpack sprayer with two TX-4 hollow cone spray tips (Spraying Systems Co.) positioned 5 to 10 cm from the plant canopy (one above and one below) at 60 psi. SPW adults were counted 24 and 72 hours after treatment. Immatures were sampled on 2.1 cm diameter leaf disks and numbers were recorded by instar 24 and 120 hours after treatment.