This year has started off much like 2008 with frequent rains keeping folks out of the field in many parts of Arkansas. (I should know better than to write about the weather. Every time I do, the weather has changed by the time you read my article.)
The rains have put rice planting way behind and a lot of folks are sure antsy. Surprisingly, most of my callers have remained upbeat. Of course, farmers have to be upbeat by nature and since we cannot change the weather, they have no choice but to remain upbeat and ride it out. This too shall pass.
In fact, all too often when it stops raining, the sun shines, and the wind blows, a lot of rice that has been planted will need flushing in a week. That is always a bummer after it has rained a month.
There is a lot of rice planted and we will get the crop in. One thing last year demonstrated is we can make a good rice crop even if it is planted late. Maybe this year we won’t have two hurricanes before we can get the crop out!
Hopefully on the rice that has been planted, you have been able to get residual herbicides applied ahead of some of the rains. If we keep getting showers, keep getting the residuals in between them. If it dries and you have to flush to break a crust or chase the salts back down, take advantage of the flush and get a residual in front of it.
RiceBeau was introduced last year and has received quite a bit of play this spring. It is a mixture of propanil and thiobencarb (the active in Bolero). A gallon contains 3 pounds each of active propanil and thiobencarb.
Because Bolero is an older herbicide that has not received much attention in recent years, several have called asking for a refresher course. It was introduced into rice in the 1970s as a preplant treatment for water-seeded rice, a delayed pre-emergence treatment for dry-seeded rice, and as a tank mix with propanil.
When used alone, the rate was 4 pints (4 pounds active) per acre. The first tank mix recommendations were for 3 quarts of propanil and 3 pints of Bolero 8E (3 pounds active each).
A later recommended option was to use 2 to 3 quarts of propanil and 2 pints of Bolero each in a split shot treatment. The split shot treatment provided 4 pints of total Bolero, which extended the residual period some and also reduced some injury potential on high pH or high salt situations.
We also added a Bolero plus Facet delayed pre-emergence recommendation. All of those treatments remain in the MP-44.
(MP-44 refers to the University of Arkansas Extension publication “Recommended Chemicals for Weed and Brush Control for Arkansas 2009” which can be purchased online at UA publications/Weed Control. A pdf of the publication is available online at Recommended Chemicals for Weed Control.)
Bolero has good activity on sprangletop, barnyardgrass and most aquatics. In the day we recommended a lot of propanil plus Bolero mixtures over propanil alone, it was primarily for sprangletop control, residual barnyardgrass control and suppression of aquatics.
Between then and now, better options came along for all three situations and Bolero essentially dropped off the radar. In addition, propanil plus Bolero at the 3 plus 3-pounds rate could be tough on the rice on hot days in high salt or high pH situations.
If you fast forward to today, some are asking, “Where does it fit?” Hopefully the above comments from the past will shed some light. Today it will go out primarily as a tank mix with Command, Facet or Newpath, which is different from the past and can make it a nice treatment. The treatment component it still must be compared to is a gallon of propanil in the above mixtures.
The RiceBeau rate being emphasized is 3 quarts, which gives you a little over 2 pounds active for each component. If used alone, this rate is too low for most situations. However, if the tank-mix component adds to the activity, this rate may be fine. Still, the timing needs to be very early.
Also, Bolero has more soil activity than postemergence activity, so it must receive moisture for activation. However, the tank mix component will need activating anyway. It also offers the opportunity to add another mode of action for resistance management. If additional sprangletop control, a bump in barnyardgrass residual, or aquatic suppression is needed, it can have a fit. In other situations, you may like a gallon of propanil better.