a methyl bromide alternative ( Allaire et al., 2005 ; Ma et al., 2001 ; Schneider et al., 2006 ). In 1957, Dow Chemical Company was granted a patent for propargyl bromide as a soil fumigant. However, it subsequently was taken off the market because
Inga A. Zasada, Clyde L. Elmore, Lani E. Yakabe, and James D. MacDonald
Theodore P. McAvoy and Joshua H. Freeman
The use of MBr has been instrumental for the management of soilborne pests in many vegetable crops that use the plasticulture production system. Vegetable producers rely on soil fumigants to maintain successful production. However, MBr was found to
Charles L. Wilson, Jose M. Solar, Ahmed El Ghaouth, and Deborah R. Fravel
An apparatus was developed for the rapid and facile evaluation of soil fumigants in a controlled manner using small volumes of soil. The apparatus consisted of a manifold to which were attached six canisters containing a loamy sand soil (adjusted to –100 kPa soil water potential). The soil was infested with either conidia of Fusarium oxysporum or Trichoderma harzianum; sclerotia of Sclerotinia minor; ascospores of Talaromyces flavus; vermiculite colonized with Pythium aphanidermatum; or beet (Beta vulgaris L., cv. Detroit Red) seed colonized with Rhizoctonia solani. Using nitrogen gas (N2) as a carrier gas, either N2 or N2 plus benzaldehyde was passed continuously through the soil for 24, 48, or 72 hours. At all three exposure times, benzaldehyde + N2 reduced viability of R. solani and S. minor, and reduced populations of P. aphanidermatum and T. harzianum. Populations of F. oxysporum were reduced after 48 and 72 hours of exposure to benzaldehyde, whereas populations of T. flavus were reduced only after 72 hours of exposure. Fumigation with benzaldehyde + N2 for 24 hours did not affect soil pH 1 week after exposure, but fumigation for 48 or 72 hours temporarily lowered pH from an average of 6.86 to 5.57 and 5.32, respectively. The biocontrol fungus, T. flavus, was less sensitive to benzaldehyde than the pathogens or the biocontrol fungus, T. harzianum. Thus, combining T. flavus with benzaldehyde to enhance biocontrol may be possible.
Matthew D. Jeffries, Travis W. Gannon, W. Casey Reynolds, Fred H. Yelverton, and Charles A. Silcox
significant revenue losses associated with the prolonged regrassing period, and potentially compromise establishment of subsequent warm-season turfgrasses by reducing the establishment period before dormancy onset. Dazomet is a granular soil fumigant designed
Steve Kovach, James Brown, Walter Hogue, Larry Curtis, and William S. Gazaway
Drip-irrigated tomato (`Sunny') plants were treated with five levels of fumigant in combination with three levels of mulch. Fumigants were metham sodium at two rates, 475 and 950 L/ha, a 67% methyl bromide + 33% chloropicrin formulation (164.5 kg/ha, and a 98% methyl bromide + 2% chloropicrin formulation (329 kg/ha). Mulching levels were 1.25 mil silver on black polyethylene (plastic), blue-black latex mulch sprayed over the plant beds, and no mulch. Plants treated with metham sodium (950 L/ha) had a significantly higher number of marketable fruit than plants treated with no fumigant or the 98% methyl bromide + 2% chloropicrin formulation. Marketable fruit weight was not significantly affected by the five fumigation levels. Plants grown with black plastic mulch had a significantly higher marketable yield than plants grown with no mulch, 58,100 kg/ha vs. 50,800 kg/ha, respectively. The level of mulching did not significantly affect the marketable number of fruit.
Robert E. Uhlig, George Bird, Robert J. Richardson, and Bernard H. Zandstra
A field study was conducted to evaluate fumigant alternatives for methyl bromide (MB). Iodomethane (IM), chloropicrin (CP), 1,3-dichloropropene (1,3-D), metham sodium (MS), and MB in various combinations were applied to a sandy soil field site in Sept. 2002. Some treatments were tarped. Plant injury, plant growth, fresh weight, and dry weight were evaluated for seven ornamental species: cushion spurge (Euphorbia polychroma), globe thistle (Echinops bannaticus ‘Blue Globe’), common lavender (Lavandula angustifolia ‘Hidcote Blue’), hosta (Hosta ‘Twilight PP14040’), silvermound artemisia (Artemisia schmidtiana ‘Silver Mound’), shasta daisy (Leucanthemum ×superbum ‘Snow Lady’), and thread leaf coreopsis (Coreopsis verticillata ‘Moonbeam’). Weed control was evaluated in Apr. 2003, July 2003, and May 2004. All treatments gave almost complete control of all annual weeds, except for IM 50% + CP 50% (200 lb/acre, tarped) and MS (75 gal/acre, 1:4 water, not tarped), which did not give adequate control of common chickweed (Stellaria media), mouseear cress (Arabidopsis thaliana), common lambsquarters (Chenopodium album), or common purslane (Portulaca oleracea). None of the treatments caused visual injury to any crop species. Treatments did not affect plant size in Nov. 2003. However, some treatments resulted in larger thread leaf coreopsis and silvermound artemisia plants in May 2004. There was no difference in dry weight at harvest between treatments for all species.
James P. Gilreath, Bielinski M. Santos, Joseph W. Noling, Salvadore J. Locascio, Donald W. Dickson, Erin N. Rosskopf, and Steven M. Olson
Field studies were conducted in three Florida locations (Bradenton, Gainesville, and Quincy) during 1998-99 and 1999-2000 to: 1) compare the performance of two transplant systems under diverse MBr alternative programs in `Chandler' strawberry (Fragaria ×ananassa), and 2) determine the efficacy of these treatments on soilborne pest control in strawberry. Fumigant treatments were: 1) nonfumigated control, 2) methyl bromide plus chloropicrin (MBr + Pic) at a rate of 350 lb/acre, 3) Pic at 300 lb/acre and napropamide at 4 lb/acre, 4) 1,3-dichloropropene (1,3-D) plus Pic at 35 gal/acre and napropamide at 4 lb/acre, 5) metam sodium (MNa) at 60 gal/acre and napropamide at 4 lb/acre, and 6) MNa followed by 1,3-D at 60 and 12 gal/acre and napropamide at 4 lb/acre, respectively. Strawberry transplants were either bare-root or containerized plugs. There were no significant fumigant by transplant type interactions for strawberry plant vigor and root weight per plant, whereas ring nematode (Criconema spp.) and nutsedge (Cyperus rotundus and C. esculentus) populations, and total marketable fruit weight were only infl uenced by fumigant application. The nonfumigated plots had the lowest strawberry plant vigor and root weight per plant in all three locations. In most cases, plant vigor and root biomass per plant increased as a response to any fumigant application. With regard to the transplant type, bare-root transplants had similar plant vigor as plugs in two of the three locations. Fumigation improved nutsedge and ring nematode control. All fumigants had higher early and total marketable yield than the nonfumigated control, whereas transplant type had no effect on total fruit weight.
Joseph F. Costante, Wesley R. Autio, and Lorraine P. Berkett
`Rogers Red McIntosh' apple (Malus domestica Borkh.) trees on MM. 111, MM. 106, M.7a, or M.26 were planted in 1984 on an old orchard site, diagnosed with an apple replant disease (ARD) problem. Soil treatments included Telone c-17, Vorlex, Nemacur 3, or not treated. After six years, tree performance problems usually associated with severe ARD did not develop. Lesion nematode [Pratylenchus penetrans (Cobb) Filipjev and Schuurmans-Stekhoven] populations feeding within or on the surface of roots were not affected by nematicide treatments nor rootstocks, even though slightly damaging levels were found in 1986. At the end of the sixth growing season, trunk cross-sectional areas were similar for trees in treated and in untreated soils. Trees on MM. 111 and MM. 106 were the largest, and those on M.26 were the smallest. Cumulative yield was not influenced by soil treatments, but trees on MM. 111 produced the greatest cumulative yields, whereas trees on M.26 were the most yield efficient.
Bielinski M. Santos, James P. Gilreath, and Timothy N. Motis
Field trials were conducted from 1999 to 2003 to determine whether chloropicrin (Pic) stimulates nutsedge (Cyperus spp.) emergence through polyethylene mulch, and to examine at which Pic rate the stimulatory effect is maximized. Shank-injected Pic rates were 0, 50, 100, 150, 200, and 250 lb/acre. Application rates between 107 and 184 lb/acre of Pic stimulated nutsedge sprouting through polyethylene mulch by 60%, 400%, 58%, and 120% more than the nontreated control during four of the seasons. Rates above 250 lb/acre eliminated the stimulatory effect on nutsedge, reducing densities to the same levels as the nontreated control. The exact physiological mechanism of this stimulation is still unknown.
E. A. Estes, W. A. Skroch, T. R. Konsler, P. B. Shoemaker, and K. A. Sorensen
Staked tomatoes (Lycopersicon esculentum Mill) grown in 8 soil management systems are compared for differences in marketable yields, gross revenues, treatment costs, and net economic values. Maximum marketable yields were obtained using a fumigant and straw mulch combinatory practice, but the highest net economic value (gross revenues less treatment costs) was realized by a fumigant and herbicide ground management practice. These data suggest that the use of mulch materials and/or herbicides increased yields and net returns over standard cultivation practices.