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Serving: Central

Dry spring affects weed control

This year is starting off to be much different from last year. There is some rain in the forecast and we need one in most areas of Arkansas.

Unless we start getting more timely rains, things could get interesting in a hurry. In the rather small area I’ve traveled this year, I have already seen more rice flushed so far this year than I saw flushed all last year. In a dry year, you simply have to get on top of weeds much more quickly in both rice and soybeans than you do in a wet year.

In rice, the performance of the residual herbicide program usually determines both the cost and success of the weed control program. I know a lot of Command has been put out and not activated timely. I have also had a lot of calls from folks holding off on their Command or residual program waiting on a better forecast of rain.

First, check the dry fields closely for small grass if you have waited to apply Command or if it has not been activated. Just because it has been too dry to get rice up doesn’t mean the grass will not come up. The Command may need quinclorac added to it or a postemergence herbicide like Ricestar HT or propanil added.

If flushing is required, take advantage of the flush to activate some residual. Often, flushing to get a stand means two flushes. If this is the situation, get some residual herbicide out in front of both flushes. If you have applied Command and flushed or caught a rain, you can use another half rate of Command in a split, come back with a quinclorac product in front of the second flush, or switch to something like Prowl or Bolero or a combination of any of these.

If the Command treatment has been delayed waiting on a rain, consider adding a pint of crop oil concentrate to it in case you have any emerging seedling grass that may not be seen. This will add a little activity on emerged grasses. However, if you know you have emerged grass, add quinclorac or a postemergence herbicide.

If grass has emerged through the residual treatment, it must be controlled before it gets past the four-leaf stage or it could be a dog fight the rest of the year. If the soil is dry, time the postemergence treatment behind a rain or flush. Ricestar HT plus quinclorac or Command has been a nice early postemergence treatment the past couple of years.

If broadleaf weeds are also emerged, Broadhead (quinclorac plus Aim) is an option. Adding Permit or Halomax to the early postemergence treatment can provide some broadleaf residual control.

Do not skimp on the rates on the first postemergence treatment as this treatment could determine what the rest of the year could be like. There are other combination treatments such as propanil or RiceBeau, Clincher or Regiment plus Command or quinclorac that can also have a good fit. I am more concerned that you do something timely and with good moisture than I am concerned about what the specific treatment is at this point.

If the field is planted to Clearfield rice, look to combination treatments such as Clearpath or add another postemergence herbicide to the first Newpath treatment if grasses have emerged.

In soybeans, a lot of pre-emergence herbicides have been applied that have not been activated or were not activated timely.

If you have a resistant pigweed problem and the field is planted to Roundup Ready or conventional soybeans, you have 10 to 14 days after emergence to get the pigweeds under control or it is over. Flexstar and Ultra Blazer are the two options for control. Hit the pigweeds hard when they are tiny and repeat the treatment in seven to 10 days. If Prefix was used pre-emergence and you are rotating the field next year, you are limited on Flexstar use, so Ultra Blazer may be a better option.

If the field is in LibertyLink soybeans, apply 22 ounces of Ignite at 10 to 14 days after emergence and repeat in seven to 10 days after the next flush emerges. If things have gotten out of hand in the LibertyLink field, you have the 36-ounce option for the first application. Follow with another 8 ounces (you are limited to 44 ounces total Ignite) and add Flexstar or Ultra Blazer in the second application.


TAGS: Management
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