Control of Insects on Fresh Market Tomatoes in West-Central Florida, Spring 1994

Abstract

Abstract On 10 Mar, transplants were set 18 inches apart on raised beds of EauGallie fine sand covered with black polyethylene mulch. Plots were 3-18 ft long rows on 5 ft centers and were irrigated by a seepage subirrigation system. Insecticidal sprays were replicated 4 times in a randomized complete block design and were applied with a high clearance, self-propelled sprayer on 5, 12, 19, 26 Apr, 3, 10, 17, 26 May, and 2 Jun. The sprayer was operated at 200 psi and 3.4 mph and used hollow cone nozzles fitted with #3 disks and 25° cores. The number of nozzles per row was increased from 4 to 8 to increase gallonage as the plants grew. Thus, 60 gpa were applied the first four sprays (4 nozzles), 90 gpa the next two sprays (6 nozzles) and 120 gpa for the remaining three sprays (8 nozzles). Admire treatments were applied in 4 oz water/plant on 29 Mar. All control and yield data were collected on the middle 10 plants of the middle row of each plot. The terminal leaflet was collected from a leaf from the upper third of each of ten plants on 18 Apr, 23 May, and 7 Jun. The number of eggs, crawlers, sessile nymphs, pupae and pupal exuviae of the silverleaf whitefly were counted. Counts were totalled over all dates for analysis. On 3 May, all plots were inadvertently sprayed with a combination of Danitol 2EC and Monitor 4EC (0.2 and 0.75 lb Al/acre, respectively). On 5 May, the number of southern armyworm larvae that had been killed by the misapplication was counted on the plastic soil mulch in each plot. On 13 Jun, the numbers of leafmines and leaf rolls of the tomato pinworm were counted in a 2 min whole plant search of each plot. All fruit of marketable size were harvested on 25 May and 10 Jun, separated by the presence of tomato pinworm and southern armyworm damage, counted and weighed. On the last harvest date, a maximum of 100 fruit per plot were examined and rated 1 to 4 for increasing severity of irregular ripening, a disorder associated with high populations of the silverleaf whitefly. Ratings of 3 and 4 are considered unmarketable.