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ARS Home » Southeast Area » Tifton, Georgia » Crop Protection and Management Research » Research » Publications at this Location » Publication #200589
Title: Lack of nutsedge efficacy is a problem when halosulfuron is applied through drip irrigation

Author
item Webster, Theodore
item GREY, T - UNIV. OF GA, TIFTON, GA
item CULPEPPER, A - UNIV. OF GA, TIFTON, GA

Submitted to: International Conference on Methyl Bromide Alternatives and Emissions Reductions
Publication Type: Proceedings
Publication Acceptance Date: 9/16/2006
Publication Date: 11/6/2006
Citation: Webster, T.M., Grey, T.L., Culpepper, A.S. 2006. Lack of nutsedge efficacy is a problem when halosulfuron is applied through drip irrigation. In: Proceedings of the International Conference on Methyl Bromide Alternatives and Emissions Reductions, November 6-9, 2006, Orlando, FL. p. 129.1-129.4.

Interpretive Summary: The search for methyl bromide has included many currently registered fumigants. While these fumigants have activity on many pests, nutsedges are not adequately controlled. Purple nad yellow nutsedge are the most troublesome weeds species in vegetables in the Southeast US. Halosulfuron-methyl effectively controls nutsedges and is registered for use in some vegetable crops. However, lack of crop tolerance to halosulfuron in crops such as eggplant, bell pepper, and summer squash has prevented the wide-spread adoption of this effective nutsedge tool. Application of halosulfuron through drip irrigation lines may be one means to avoid crop injury. If successful, this would also provide a means of controlling nutsedges in second- and third-crop use of the same low density polyethylene (LDPE) mulch bed; situations in which the use of alternative fumigants is limited. Based on field studies, it is concluded that: 1)Injury to eggplant and cucumber from halosulfuron was minimized by application through drip irrigation lines following transplant; 2) Halosulfuron applied through drip irrigation lines did not provide effective nutsedge control; 3) Attempts to improve lateral movement through manipulation of the soil pH were inconsistent and even contrary to what was predicted; 4) While a promising idea for managing nutsedge populations in crops sensitive to topical-over-the-top applications of halosulfuron, it does not appear that application through drip irrigation will be a viable methyl bromide alternative for nutsedge management.

Technical Abstract: Many proposed methyl bromide alternatives have provided sub-standard control of nutsedges. Halosulfuron-methyl effectively controls nutsedges and is registered for use in some vegetable crops. However, lack of crop tolerance to halosulfuron in crops such as eggplant, bell pepper, and summer squash has prevented the wide-spread adoption of this effective nutsedge tool. Application of halosulfuron through drip irrigation lines may be one means to avoid crop injury. If successful, this would also provide a means of controlling nutsedges in second- and third-crop use of the same low density polyethylene (LDPE) mulch bed, situations in which the use of alternative fumigants is limited. Based on field studies, it is concluded that: 1)Injury to eggplant and cucumber from halosulfuron was minimized by application through drip irrigation lines following transplant; 2) Halosulfuron applied through drip irrigation lines did not provide effective nutsedge control; 3) Attempts to improve lateral movement through manipulation of the soil pH were inconsistent and even contrary to what was predicted. By raising the soil pH, halosulfuron dissipation may also have been accelerated which resulted in decreased residual control for nutsedge; 4) While a promising idea for managing nutsedge populations in crops sensitive to topical-over-the-top applications of halosulfuron, it does not appear that application through drip irrigation will be a viable methyl bromide alternative for nutsedge management.