Rice Weed Control 101

I Forgot To Mention Command

Andy Kendig, State Extension Weed Specialist

Printed/Posted with permission of Mid America Farmer Grower

Perhaps you noticed that none of the previous articles mentioned Command. That is because Command does not have a registration for use on rice at this time. Last year's Section 18 use was only for very special circumstances where propanil-resistant barnyardgrass existed and where Facet could not be safely used. Nevertheless, you probably heard good reviews about the "general weed control value" of Command.

When Command is registered, it will be the only herbicide that is actively recommended for true preemergence, immediate post-plant application. For the sake of fairness, Facet is currently registered for true pre/immediate post -plant application, but because of rotational flexibility and moisture requirements, it is generally promoted as delayed preemergence or early postemergence.

More important than application flexibility is the fact that Command costs less than $10.00 per acre and offers relatively good, relatively dependable grass control without strict moisture requirements. Just to reemphasize, Command's low cost benefits have nothing to do with Section 18 Emergency Labels. At this time there is neither a regular registration nor a Section 18 emergency registration.

There are three limitations to Command: 1) It can turn rice white, 2) it controls few broadleaves and 3) like any other rice herbicide- it may not provide perfect grass control. On a silt loam soil, rice is likely to have a white color during the first few weeks after emergence. Normally, the rice quickly recovers and there is no yield loss. However, research has indicated that yield can be reduced in areas where the rate is doubled. So, Command should be sprayed carefully. On a heavy clay soil, you may notice little or no rice injury.

The majority of rice herbicides provide solid broadleaf weed control. But, Command, Prowl and Whip provide little or no broadleaf weed control. Growers using any of these herbicides should plan to make a broadleaf cleanup application around the time of flooding. For grasses, we have observed good, but not perfect weed control from Command. However, in Missouri conditions it has been the second most reliable residual herbicide and costs 1/4 of the most reliable. But the take home message with Command (and any other herbicide for that matter) is to scout carefully and see if a preflood grass clean up is needed. Remember, small grass can be controlled economically, big grass can sometimes be controlled, but it'll be expensive.

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