Control of Dbm, 1988:

‘Rio Verde’ cabbage seeds were incorporated into a germination mix (Pro-Mix) and direct seeded into a Rockdale soil at the University of Florida’s Tropical Research and Education Center on 14 Dec 1987. The soil was fumigated with Terr-O-Gas (75% methyl bromide; 25% chloropicrin; 220 lb/acre) and covered with blue plastic mulch on 25 Nov 1987; mulch was perforated on 11 Dec. Plants were sprinkler irrigated twice/week (0.75-1.00 inches/acre). Treatments were replicated 4 times in a randomized complete block design. Treatment plots were 4 rows (2 beds) wide by 40 ft long. A 10-ft-long section of untreated plants separated replicates; treatments within a replicate were separated by one untreated bed and a 6-ft alleyway. Teflubenzuron (CME 13406) (0.03 lb [AI]/acre) efficacy and residual activity were evaluated using 3 treatment intervals, applications made weekly, once every 2 wk, and once every 3 wk. Weekly applications of Lannate + Dipel, Pydrin, and CME 13406 were made on 10 dates: 14, 21, and 27 Jan; 3, 10, 17, and 24 Feb, and 2, 9, and 16 Mar. Treatments of CME 13406 at 2- and 3-wk intervals were applied on 5 dates (21 Jan, 3 and 17 Feb, and 2 and 16 Mar) and 3 dates (21 Jan, 10 Feb, and 2 Mar), respectively. Treatments were applied using a tractor-mounted single-bed boom sprayer that operated at 250 psi and delivered 100 gal/acre through 5 D-4 #24 disk-type cone nozzles at 3 mph. Sample plants were chosen from among the center 30 plants in the two middle rows in each treatment plot. The numbers of small, medium, and large DBM larvae and pupae were recorded on 8 plants/replicate, 32 plants/treatment, on 11 dates. Foliar damage was rated on 8 plants/replicate on 4 and 11 Mar and on 24 plants/replicate on 21 Mar using a 1-6 scale (1, no apparent insect feeding to 6, severe damage to head and wrapper leaves). Percentages of marketable heads were determined on 21 Mar based on ratings ≤3.