Cutworm and Flea Beetle Control on Flue-Cured Tobacco, 1994

Abstract

Abstract This experiment was conducted at the VPI & SU Southern Piedmont Agricultural Research and Extension Center, Blackstone, VA to evaluate TFB and CW control on newly transplanted tobacco with soil applications of fosthiazate and Lorsban and a transplant water (TPW) application of Orthene. Four treatments and an untreated control were established in a randomized complete block design with 4 replications. Plots, 4 × 20 ft (1 row × 13 plants), were separated by single untreated border rows. Pretransplant soil treatments of fosthiazate and Lorsban were applied broadcast with a CO2-pressurized back-pack sprayer that delivered at 48 gal/acre and 30 psi through 8004LP tips and immediately incorporated by tilling on 8 Sep. The soil was relatively dry when the chemicals were applied. The test plots were bedded on 9 Sep. The Orthene TPW treatment was applied in 180 gal solution/acre using a hand transplanter at transplanting. ‘K-326’ flue-cured tobacco was transplanted into experimental plots in a Chesterfield-Mayodan-Bourne sandy loam soil on 12 Sep and a second group of plants were transplanted between the original plants on 16 Sep. CW were collected within 2 wks of transplanting under clumps of discarded tobacco leaves located around the margins of fields of mature tobacco. Cutworms were stored in moist sand with tobacco leaves for food at about 50°F. CW were sorted by size and species so that treatments within blocks would receive larvae of similar size and species. Individual CW were placed in the soil about 3 inches from 10 plants in each plot immediately after the first planting. No additional CW were released after the second planting. The test was irrigated with 0.25 inch immediately after transplanting and 1.0 inch on 16 Sep. The number of plants damaged and cut by CW were counted in each plot and each transplanting date on 17 and 23 Sep. TFB feeding holes in the most damaged leaf were counted on 10 plants/transplanting date/plot on 26 Sep. On 23, 26 and 29 Sep, TFB damage was rated on a scale of 0 to 10 where 0 = no feeding damage and 10 = very severe damage. Tobacco plants were dug up on 29 Sep, weighed, and rated for TFB damage. CW injury was analyzed within each transplanting date. TFB data and seedling weights were combined over the two transplanting dates. Data were analyzed by ANOVA and significantly different means were separated by WD (K-ratio = 100).