Sorghum cover crop and repeated soil fumigation for purple nutsedge management in tomato production

BACKGROUND Purple nutsedge (Cyperus rotundus L.) is one of the most common and troublesome weeds. Field research trials were conducted in Florida to evaluate the effects of repeated fumigation and a sorghum sudangrass [Sorghum bicolor S. bicolor var. sudanense (Piper) Stapf.] cover crop on purple nutsedge (Cyperus rotundus L.) populations over time in tomato (Solanum lycopersicum L.) production. RESULTS Among the soil fumigants, DMDS + metam potassium was consistently the most effective treatment in terms of in-crop purple nutsedge control. Plots with a sorghum cover crop during the fallow period exhibited higher purple nutsedge density during the tomato growing season as well as higher purple nutsedge shoot and tuber densities during the fallow period compared to the chemical fallow. CONCLUSION DMDS + metam potassium was the most effective fumigant for purple nutsedge control. Unexpectedly, a sorghum cover crop during the fallow period was less effective than chemical fallow for purple nutsedge management, and therefore we do not recommend the use of sorghum cover crops for weed management in fields where purple nutsedge is the major weed species.

Automated summary

DMDS + metam potassium proved to be the most effective fumigant for controlling purple nutsedge in tomato production. Unexpectedly, a sorghum cover crop during fallow periods was less effective than chemical fallow for managing purple nutsedge, leading to the conclusion that sorghum cover crops are not recommended for weed management in fields where purple nutsedge is the major weed species.