March 2017 Articles

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Farmers hear latest crop production information

Farmers hear latest crop production information Writer: Bruce Schultz at 337-788-8821 or bschultz@agcenter.lsu.edu
(02/13/17) DELHI, La. – Continuously growing cotton or soybeans in the same field can result in a buildup of reniform nematodes, LSU AgCenter plant pathologist Charles Overstreet
told producers at the Northeast Louisiana Crops Forum on Feb. 9. Rotating cotton or soybeans with another crop can reduce the problem. “One year of corn is good. Two years is better,” he said. Three cotton varieties have shown resistance to root knot nematodes, but no varietal resistance has been found for reniform nematodes, he said. Research is showing nematode fumigants are effective in lighter soils, but little response has been obtained in heavier soils, Overstreet said. AgCenter weed scientist Josh Copes said farmers should be eliminating Italian ryegrass from fields to be planted in corn. Two applications of paraquat or one application with paraquat and metribuzin is needed to obtain a clean seedbed. State rules for using the new herbicides Extendimax and Engenia are being written. Farmers will have to be mindful of the potential for drift when using the products that contain dicamba, he said. Tanks containing dicamba will require extensive cleaning to remove all traces of the chemical, Copes said. AgCenter plant pathologist Trey Price said farmers should treat all cotton seed with fungicides. “Do not plant cotton without fungicide seed treatments, or you are setting yourself up for failure,” he said Target spot disease was found on most cotton grown in Louisiana last year, but hardly any was found in 2015 because of dry weather. Target spot that occurs two to three weeks after bloom will result in a yield loss, but disease in later growing stages will probably not reduce yields, Price said. Soybean diseases Cercospora leaf blight and frogeye leaf spot are resistant to some fungicides, and he said corn diseases will eventually develop resistance. Research has confirmed the fungus responsible for taproot decline. The problem is most often found in fields where consecutive soybean crops are being planted in no-till fields. The problem can be addressed with cultivation and planting corn in rotation, Price said. “It also is possible that we may have some commercially available varieties resistant to taproot decline. We hope to have a preliminary list of resistant varieties before planting this year,” he said LSU AgCenter soybean specialist Ron Levy said farmers with resistant pigweed will have a new dicamba-tolerant soybean variety available this year in the Xtend technology. “While we anticipate seeing some issues with buffer zones, sprayer clean out and off-target movement either through volatilization or drift with this technology, this will be a good product for soybean producers,” he said. The new technologies available now, and for those expected to be released in 2018, will offer different modes of action for specific weeds, Levy said. Mid-April is the optimum planting date for most varieties, with group V varieties seeing higher yield results from planting as early as late March, he said. More information on maturity dates, planting dates, disease ratings, company names and varieties are available in the AgCenter publication 2016 Soybean Variety Yields and Production Practices (LSU AgCenter Publication 2269), he said. AgCenter entomologist Sebe Brown said seed treatments should be used to prevent injury from thrips in cotton. Aldicarb will be available this year to use against the insect. Seed treatments for corn are effective against wireworms, increasing yields by 14.4 bushels an acre, Brown said. He advised against using a pyrethroid in soybeans unless stinkbugs are found. Using the pesticide without adequate justification will result in eliminating beneficial insects. Brown advised farmers to budget for three insecticide applications this year for red-banded stinkbugs, but some fields may have to be sprayed up to five times. Spraying before the R-5 stage has no benefit. Issues from last year’s flooding have increased the need for corn producers to know more about whether to replant, said AgCenter corn specialistDan Fromme “After two years and 12 trials, we have some really good information to indicate that corn yields drop drastically when plant populations drop below 27,000 plant population per acre,” he said. Fromme reported that results from on-farm trials in central Louisiana on corn nitrogen rates following soybeans were surprising, showing economically optimum yields with applications as low as 150 to 175 pounds per acre in some locations. “In this area where nitrogen rates are typically higher, and with corn prices as low as they are, these trials offer great value,” he said. Fromme also discussed the value of cotton variety trials and encouraged producers to review the 2016 Cotton Varieties for Louisiana (LSU Ag Center Publication 2135) for the latest on farm demonstration and variety trial results. (LSUAgCenter Publication 2135) for the latest on farm demonstration and variety trial results.