New rice herbicide proven in tests I ended last week's article abruptly with the data table from one Command study last year. I'll follow that up with some further comments.
The purpose of the article was not to advocate a wholesale lowering of the rates. I traveled the rice-growing area rather extensively last season and saw very few fields with unacceptable Command injury caused by the rate being too high.
I did see about every type of application error that could be made. I don't mean to sound harsh, but too many applicators, whether private or commercial, are used to applying herbicides with which about the only way you can mess up is by missing weeds due to skipped places.
However, in some situations Command isn't so forgiving. Everyone who plans to apply it this season needs to tighten up on application technique, sprayer setup, proper agitation, rate calculation, etc.
Command was probably as active last year as we will ever see it. If you were happy with your rate last year, there is no reason to back off any.
The federal label was just issued (meaning we do not have to have a Section 18 this year) and FMC did not waiver on rates any. The lowest labeled rate is 1.125 pints per acre. FMC also says that "if the field has been leveled within 12 months, expect more injury."
Rice grown on most of our silt loam soils will tolerate the labeled rate of 1.125 pints per acre. Injury has rarely been a problem on the clay soils with any rate. However, we have a lot of silt loam fields where the rate of 12.8 ounces per acre is plenty. In fact, that is my favorite rate across the board on the silt loams. It is more "forgiving," and it is certainly a better rate if Bengal or perhaps Cocodrie will be planted.
From what I saw last year, time elapsed since the field was leveled made little difference. The depth of the cuts were far more critical. The research area where the data in last week's article came from had been leveled five years ago. However, it was in an area cut about a foot and the area still has a reddish color instead of the normal white.
Rice will tolerate a lot of Command injury and make normal yields. Plots with injury severe enough to cause stand thinning often have been some of the highest-yielding plots in the study. However, when injury occurs severe enough to take the stand out in areas so large that the remaining plants cannot compensate, then yields have to go down.
There are a couple of take-home messages from the data presented in last week's article. (If you miss an article, they are on the Delta Farm Press (www.deltafarmpress.com and our Extension web sites). If you did not get unacceptable injury from the rate used last year, stay with it. However, it shows there are soils where 1.125 pints per acre is too much. The yields in that study were dropping fast. On that soil, the 12.8-ounces-per-acre rate was acceptable but a 0.5-pint-per-acre rate was even better. I saw a few fields last year where 12.8 ounces per acre was too much.
The severe yield reduction from the "double-up" rates of 0.6 and 0.8 pound active ingredient per acre show that these type application errors sometimes can't be tolerated. I have said in several articles before, you will have to do the final "fine tuning" of rates to your individual fields.