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  • Author or Editor: David B. Langston Jr. x
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The phase out of methyl bromide has precipitated a need to reduce usage of the all purpose fumigant. Reduction in methyl bromide use can extend the life of existing stocks and make it more likely to continue critical use exemption for future production. Traditional widths for plastic mulch covered beds in Georgia ranges from 32 to 36 inches. By reducing bed top widths, it could be possible to reduce the amount of methyl bromide applied by as much as 60%. The objectives of this work were to evaluate the effects of narrower bed tops and lower rates of methyl bromide on pepper and cantaloupe growth and yield. Bed top widths of 36, 30, and 24 inches were each tested with broadcast rates of 400 and 300 lb/acre of both 67:33 and 50:50 methyl bromide-chloropicrin at Tifton, GA in the fall of 2005. Bed widths were the main plot and methyl bromide rates the sub plot. Plots were 20 feet long with two rows of pepper planted per bed with 12 inches between plants and one row of cantaloupe planted per bed with two feet between plants. All beds were on 6-ft centers and fertilizer rates were constant across plots within a crop. There were four replications. Otherwise normal cultural practices were employed. Crops were harvested at maturity and data collected on yield and plant growth. Pepper yields were depressed by early cold weather. The 24-inch bed tops produced significantly lower yields of extra large, large and total fruit, but had greater top dry weight and root fresh weight than the 36-inch beds. There were no differences found among methyl bromide rates for cantaloupe or for pepper except extra large fruit were greater at the highest rate compared to the lowest. There were no differences among bed top widths for cantaloupe yield or plant growth.

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Field experiments were conducted from 2008 through 2010 near Lyons, GA, to develop integrated weed management systems for organic Vidalia® sweet onion (Allium cepa) production. Treatments were a factorial arrangement of summer solarization, cultivation with a tine weeder, and a clove oil herbicide. Plots were solarized with clear plastic mulch during the summer fallow period before transplanting onion. Cultivation treatments were twice at 2-week intervals, four times at 2-week intervals, and a noncultivated control. Herbicide treatments were clove oil plus vinegar, clove oil plus an emulsified petroleum oil (EPO) insecticide used as an adjuvant, and a nontreated control. ‘Savannah Sweet’ onions were transplanted in early-December each year, with cultivation and herbicide applications events occurring the following January and February. Onions were harvested the following spring. In addition to yield measurement, a subsample of harvested onion was stored in a controlled atmospheric (CA) storage facility to evaluate treatment effects on diseases of stored onion. Summer fallow solarization did not control the cool-season weeds present in these trials. Cultivating transplanted onion with a tine weeder effectively managed cutleaf eveningprimrose (Oenothera laciniata) and swinecress (Coronopus didymus) and improved onion yields in 2 of 3 years. There was little difference in overall performance between two cultivations and four cultivations with the tine weeder. The 1 year of marginal weed control with the tine weeder was due to persistently wet soils during winter months that inhibited optimum performance of the implement. Clove oil, combined with vinegar or an EPO insecticide, provided marginal weed control and had no effect on onion yield. Diseases of stored onion were unaffected by any of the treatment combinations, although overall incidence of diseases of stored onion was higher in 2010 compared with other years. This corresponds with the 1 year of marginal weed control with the tine weeder, suggesting that the presence of weeds may be a factor related to disease incidence during storage.

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