Herbicides drift is bad this year. Roundup drift on wheat has shown up in almost every field I have been in. It is not a matter of “is there drift” but of “how bad is it?”
Acreage of sorghum — another non-Roundup-tolerant crop — is up in Arkansas. And, we have more non-GMO corn, and soybeans and, it seems, less Clearfield rice, making these crops targets for drift.
In the case of Roundup on corn, milo and rice, it is important to understand how very sensitive these crops are, especially in the 1-leaf to 2-leaf stage. Drift can pass over ditches and through trees and not leave much of a trace and then hammer a field of 1-leaf to 2-leaf rice.
Although it leaves more of a trace, Newpath is equally harmful to small non-Clearfield rice.
It can be very difficult to decide what to do to manage a rice field that Newpath or Roundup has drifted onto. Basically, there is nothing you can do except wait on the rice to recover. Especially on really small rice: it will either die or it won’t. If it does not die, it will take it a while to recover.
If the decision is made to keep the rice and it is Roundup drift, I suggest a flush when needed. With Newpath drift I would rather let the field dry up for a while. Depending on the rate of drift, the Newpath could be reactivated by a flush.
It can be hard to tell Newpath drift from Roundup drift, but lately this has been made much easier because almost all conventional rice has at least a plant or two that is Clearfield as a contaminant in the seed. So when Newpath drifts on the field, these contaminants are not injured, while a Roundup drift affects all the plants.
Eric Webster and Justin Hensley out of LSU have a great publication on the differences and effects of Roundup, Newpath and other herbicides on rice.
A lot of folks like to flush in some ammonium sulfate to speed the recovery of rice from herbicide drift. I was one of them for years. However, our research results have shown this to be ineffective, especially on younger rice that just does not have a root system extensive enough to take up nitrogen that early. On older rice we did observe a “green up” when fertilizer was applied to injured rice, but we saw no difference in yields by the end of the year.
It is hard to say whether or not early season drift of Roundup or Newpath will hurt yields. It depends on the year. I have seen everything from no effect to almost total yield loss. More often than not, the highest costs are in time, extra management, delayed flood and worry.
We have shown that a good seed insecticide treatment like CruiserMax or NipSit can help younger rice withstand a drift event and recover faster. This summer we are looking at some post-applied fertilizers and nutrients in combination with seed treatments to see if we can come up with even better recommendations. With another type of herbicide-tolerant rice on the way (Provisia) that will not tolerant Newpath, I do not see this problem going away any time soon.