Control of Rugose Spiraling Whitefly Using Biological Insecticides, 2014 * Open Access

The objective of this study was to evaluate the efficacy of selected biological insecticides alone or in combination, against rugose spiraling whitefly, a new invasive pest of ornamentals in Florida. The trial was conducted on white bird of paradise, an ornamental host under field conditions at the U.S. Horticultural Research Laboratory (USHRL). Young host plants in three gallon plastic pots were bought from a local nursery in Vero Beach, FL and naturally infested with RSW under greenhouse conditions (26 ± 3 °C and 75–80% RH). Host plants were watered as needed and fertilized using granular formula. Once plants were infested with RSW and overlapping generations observed plants were then moved outdoors into 6 × 6 × 6 ft nylon-mesh cages. Insecticides were applied curatively using a small hand held sprayer delivering 65.5 ml m ² at 211 kPa (30.6 psi). Plots consisted of 3 infested plants; applications were made on two plants and one was left untreated as a persistent source of insects to evaluate residual activity of the insecticides. The trial was setup in a RCB design with four replicates. Treatments were evaluated at weekly intervals by collecting five leaf discs (diam 1.13 cm ² ) per plot and carefully inspecting, under a dissecting microscope at 12 × . Count data were subjected to square root transformation prior to conducting ANOVA and mean separation procedures. The data presented are the untransformed means. Mean separation was performed using the Tukey’s HSD test at P <0.05.

RSW numbers varied greatly; however, observed reduction in whitefly number in all the insecticide treatments were significant compared to the check. Talus alone and in combination with PFR was found to be most effective treatment for control of RSW eggs, early instars and late instars throughout the study. The combination of Talus and PFR significantly suppressed RSW numbers soon after application, and provided 83–100% reduction in the number of eggs ( Table 1 ), 93–100% early instars ( Table 2 ), and 95–100% late instars ( Table 3 ) during the 6-wk period. Talus alone also provided significant reduction in RSW numbers compared to the check on all the sampling dates after14 DAT. PFR alone was found to be the least effective against eggs (8–78%), early instars (47–92%), and late instars (44–94%) among all the insecticides tested. No phytotoxicity symptoms were observed following any of the insecticide treatments.

Author notes