Several of product labels for rice herbicides have changed slightly for 2006. First in Clearfield Rice, there is a new supplemental label for the use of a maximum of 12 ounces of Newpath per acre per year. This is increased from 8 ounces on the main label. This Newpath can only be used in two applications of 4 ounces to 6 ounces per application and can only be used on the Clearfield varieties (131, 161, etc.) and not on the hybrids (CLXL8, XP730, etc.).
The higher rate of Newpath may be needed for severe red rice infestations, infestations of black hull red rice, which some report is more difficult to control and in some specific instances where a higher rate is desired in difficult-to-spray situations.
In my research, 4 ounces per acre followed by 4 ounces per acre has been enough in most situations. I would rather save the money on the extra 4 ounces of Newpath for an “if needed” application of Beyond.
There has been some talk of a full registration for Beyond herbicide in the near future, but for now it is only available under a 24c label that specifically says you can use 5 ounces per acre of Beyond to clean up any red rice that makes it through two 4-ounce Newpath applications.
This late Beyond application has worked very well to suppress seedhead development in escaped red rice and undoubtedly has prevented a lot of out-crossing of the Clearfield trait to wild rice biotypes.
In conventional herbicides, Gowan Company now has responsibility for the herbicide Permit. Permit at about 1 ounce per acre will provide excellent control of several species of nutsedge. It can also be added to other broadleaf herbicides for improved control of hemp sesbania, smartweed and other broadleaf weeds.
Gowan has made some label changes for 2006. Probably the most important is that Permit now can be applied after flood. There is a 48-day pre-harvest interval on Permit.
Late applications of Permit have been shown to provide excellent nutsedge control. These treatments may have little impact on rice yield, especially for lighter infestations of nutsedge, but that is an excellent time to reduce nutsedge populations for the subsequent soybean crop.
It would be very handy to tank-mix Permit with Clincher, now that Permit can be applied post-flood, but these tank mixtures can result in antagonism on grass control.
Arkansas and other states will again have 24c labels for the use of Command herbicide by air in rice. Command drift in Arkansas has not been an issue in the past two to three years and this 24c label will be expanded this year. The new 24c label will include more tank-mix partners and some three-way tank-mix partners.
At the time I am writing this, the label for Arkansas has not been released. Once it is released, we should all make a concerted effort to follow the label and use only those tank mixtures and timings that are approved.
Some other companies have expressed interest in writing their own 24c labels for Command by air, but at this time FMC is the only company that has submitted one in Arkansas.
Arkansas will also have a 24c label for higher rates of RiceStar HT herbicide. The 24c label will be for rates up to 24 ounces per acre and is written to provide growers with an option for larger grass control pre-flood.
This is an excellent treatment where Command has failed for one reason or another, where you have propanil- and/or Facet-resistant barnyardgrass, or when larger grass is the target.
Valent is recommending the use of 2 percent UAN (liquid nitrogen, either 28-0-0 or 32-0-0) with a silicon-based non-ionic surfactant for Regiment herbicide. According to some work that Dan Reynolds has done at Mississippi State University, this will increase the absorption of Regiment into susceptible grass weeds. The hope is that this will improve the consistency of Regiment on barnyardgrass control.
This would be beneficial because Regiment is an economical choice where a combination of barnyardgrass, sesbania, smartweed and annual sedge is the target. I have a graduate student evaluating the weed control efficacy of this program in the greenhouse and field. We have not previously done much research on adjuvants with Regiment.
There are probably some more label changes and updates. This is just the current information I have. I know things are going to be tough out there this year from a financial standpoint. Probably the best way to save money on rice herbicides is to make good decisions on the front end, select program approaches to weed control, spray early and try not to get into salvage situations with post-flood applications.
Bob Scott is the University of Arkansas Extension weed specialist. e-mail: [email protected]