The loss of methyl bromide (MB) as a soil fumigant has created the need for new weed management systems for crops such as strawberry (Fragaria ×ananassa Duchesne). Potential alternative chemicals to replace methyl bromide fumigation include 1,3-D, chloropicrin (CP), and metam sodium. Application of emulsified formulations of these fumigants through the drip irrigation system is being tested as an alternative to the standard shank injection method of fumigant application in strawberry production. The goal of this research was to evaluate the weed control efficacy of alternative fumigants applied through the drip irrigation system and by shank injection. The fumigant 1,3-D in a mixture with CP was drip-applied as InLine (60% 1,3-D plus 32% CP) at 236 and 393 L·ha-1 or shank injected as Telone C35 (62% 1,3-D plus 35% CP) at 374 L·ha-1. Chloropicrin (CP EC, 95%) was drip-applied singly at 130 and 200 L·ha-1 or shank injected (CP, 99%) at 317 kg·ha-1. Vapam HL (metam sodium 42%) was drip-applied singly at 420 and 700 L·ha-1. InLine was drip-applied at 236 and 393 L·ha-1, and then 6 d later followed by (fb) drip-applied Vapam HL at 420 and 700 L·ha-1, respectively. CP EC was drip-applied simultaneously with Vapam HL at 130 plus 420 L·ha-1 and as a sequential application at 200 fb 420 L·ha-1, respectively. Results were compared to the commercial standard, MB : CP mixture (67:33) shank-applied at 425 kg·ha-1 and the untreated control. Chloropicrin EC at 200 L·ha-1 and InLine at 236 to 393 L·ha-1 each applied singly controlled weeds as well as MB : CP at 425 kg·ha-1. Application of these fumigants through the drip irrigation systems provided equal or better weed control than equivalent rates applied by shank injection. InLine and CP EC efficacy on little mallow (Malva parviflora L.) or prostrate knotweed (Polygonum aviculare L.) seed buried at the center of the bed did not differ from MB : CP. However, the percentage of weed seed survival at the edge of the bed was often higher in the drip-applied treatments than in the shank-applied treatments, possibly due to the close proximity of the shank-injected fumigant to the edge of the bed. Vapam HL was generally less effective than MB : CP on the native weed population or on weed seed. The use of Vapam HL in combination with InLine or CP EC did not provide additional weed control benefit. Chemical names used: 1,3-dichloropropene (1,3-D); sodium N-methyldithiocarbamate (metam sodium); methyl bromide; trichloro-nitromethane (chloropicrin).
S.A. Fennimore, M.J. Haar, and H.A. Ajwa
Theodore M. Webster and A. Stanley Culpepper
Halosulfuron is a proposed alternative to methyl bromide for managing nutsedges (Cyperus spp.) in several vegetable crops, including cucurbits. Field studies were conducted to evaluate the crop sensitivity to halosulfuron in a spring squash (Cucurbita pepo L.)—fall cucumber (Cucumis sativus L.) rotation from 2000 to 2002. Treatments included application of halosulfuron to the soil surface after forming the bed, but before laying mulch (halosulfuron-PRE), halosulfuron applied through drip irrigation (halosulfuron-DRIP) after forming bed and laying mulch, metham applied through drip irrigation after forming bed and laying mulch, a nontreated control with mulch, and nontreated control without mulch. Each treatment was applied to both direct seeded and transplanted zucchini squash. Halosulfuron treatments reduced squash plant diameter relative to metham, however plant diameters in halosulfuron-PRE (transplant and direct seed) and halosulfuron-DRIP (transplant) treatments were not different from the nontreated control. Halosulfuron-PRE delayed squash fruit production relative to the mulched nontreated control. However, application of halosulfuron-PRE and halosulfuron-DRIP did not reduce squash yield at the conclusion of the season, relative to the nontreated control. Cucumbers were transplanted and direct seeded into previous squash plots and received either an application of halosulfuron-DRIP, or were not treated. Differences in cucumber yields were not detected with second crop treatments. Cucumbers appear to have adequate tolerance to halosulfuron, making it a potential replacement for methyl bromide for nutsedge control. Suppression of early season squash growth by halosulfuron may hinder the adoption of halosulfuron as a methyl bromide alternative for squash.
Jayesh B. Samtani, J. Ben Weber, and Steven A. Fennimore
supplement methyl bromide alternative fumigants to control weeds in strawberry HortTechnology 11 603 609 North Carolina Crop Improvement Association 2012 Strawberry plant varieties. 1 May 2012. < http://www.nccrop.com/varieties.php/17/Strawberry
Sanjeev K. Bangarwa, Jason K. Norsworthy, and Edward E. Gbur
potential methyl bromide alternatives are available in vegetable production. However, no single alternative is a stand-alone replacement for methyl bromide ( Noling, 2002 ). Thus, research efforts are needed to develop an integrated weed management program
Benjamin C. Garland, Michelle S. Schroeder-Moreno, Gina E. Fernandez, and Nancy G. Creamer
.E. Brannen, P.M. Monks, D.M. Louws, F.J. 2006 Economic evaluation of methyl bromide alternatives for the production of strawberries in the southeastern United States HortTechnology 16 118 128 Taylor, J. Harrier, L. 2001 A comparison of development and mineral
John E. Beck, Michelle S. Schroeder-Moreno, Gina E. Fernandez, Julie M. Grossman, and Nancy G. Creamer
.D. Ferguson, L.M. Poling, E.B. 2006 Economic evaluation of methyl bromide alternatives for the production of strawberries in the southeastern United States HortTechnology 16 118 128 U.S. Department of Agriculture (USDA) 2015 Agricultural statistics for 2014. U
Eva García-Méndez, David García-Sinovas, Maximo Becerril, Antońeta De Cal, Paloma Melgarejo, Anselmo Martínez-Treceño, Steven A. Fennimore, Carmen Soria, Juan J. Medina, and Jóse M. López-Aranda
.M. García-Sinovas, D. García-Méndez, E. Becerril, M. Medina, J.J. López-Aranda, J.M. 2005b Alternatives to MB for strawberry nurseries in Spain. 2004 results Annu. Intl. Res. Conf. Methyl Bromide Alternatives and
Mary C. Stevens, Rui Yang, and Joshua H. Freeman
cultivation. Proc. Annu. Intl. Res. Conf. on Methyl Bromide Alternatives and Emissions Reduc. < https://www.mbao.org/static/docs/confs/2007-sandiego/papers/115LeeBMBAO2007PosterEDN2-CHUNGetalFinal.pdf > Draycott, A.P. Last, P.J. 1971 Some effects of partial
Michelle M. Leinfelder and Ian A. Merwin
This research was supported by USDA–IREE Methyl Bromide Alternatives projects NYC-145560 and 145-530, and by CSREES project NYC-145409. The authors thank Gennaro Fazio and George Hudler for critical reviews of the manuscript.
Timothy S. Prather, James J. Stapleton, Susan B. Mallek, Tarcisio S. Ruiz, and Clyde L. Elmore
A double-tent solarization technique, which accumulates higher soil temperatures than solarization of open fields, was recently approved by the California Department of Food and Agriculture (CDFA) as a nematicidal treatment for container nurseries. Due to the need for broad-spectrum pest control in container nursery settings, this technique was tested to determine its usefulness as an herbicidal treatment. Laboratory-derived thermal death dosages (temperatur × time) for several weed species important in California, including common purslane (Portulaca oleracea), tumble pigweed (Amaranthus albus), and black nightshade (Solanum nigrum), were previously determined and the data were used as guidelines for devising treatment duration in this study. In two field experiments conducted in 1999 and 2000 to validate the laboratory data, moist soil was placed in black polyethylene planting bags [3.8 L (1 gal) volume], artificially infested with seeds of the three test species, and subjected to 0 to 24 hours of double-tent solarization after reaching a threshold temperature of 60 °C (140 °F) (about 1.5 to 2.0 h after initiation of the experiment). In 1999, samples were removed at 2, 4, 20, and 24 hours after reaching the 60 °C threshold, then incubated to ameliorate possible secondary dormancy effects. Seeds failed to germinate in any of the solarized treatments. In 2000, samples were removed at 0, 1, 2, and 6 h after reaching 60 °C. Again, apart from the nonsolarized control treatment, all weed seeds failed to germinate at any of the sampling periods, in accordance with prior laboratory thermal death results. Reference tests to estimate effects of container size on soil heating showed that soil in smaller container sizes (soil volume) reached higher temperatures, and were maintained at high temperature [above 60 °C (140 °F)] for a longer period of time, than larger container sizes. The double-tent solarization technique can be used by commercial growers and household gardeners to effectively and inexpensively produce weed-free soil and potting mixes in warmer climatic areas.