Kochia: The Early Bird Controls the Weed
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As the old adage goes, the early bird catches the worm. Well, it takes an early bird to get kochia under control. That’s because the weed moves fast: It germinates and emerges quickly. Thanks to these attributes — and others — kochia can cause serious headaches in Midwest cornfields.
Identifying Kochia
Among its fellow summer annuals, kochia is one of the first to emerge in spring. In states like Kansas, kochia can make appearances as early as February.1 Depending on where you’re located, it's possible you’ve already caught a glimpse of it this season.
When it comes to identifying kochia, the young plants have lance-shaped, dull-green, smooth cotyledons. Mature plants have round, purple-to-red stems and lance-shaped leaves that are grayish-green and flat. Both the leaves and stems of adult kochia have hairs.
Herbicide-resistant Kochia
According to WeedScience.org, 16 states have reported herbicide-resistant kochia in crops. Populations of kochia have been found with resistance to four herbicide groups: 1
- Group 2 (ALS inhibitors)
- Group 4 (synthetic auxins)
- Group 6 (photosystem II inhibitors)
- Group 9 (EPSP synthase inhibitors)
The weed develops resistance easily because it has high genetic diversity and a short germination period.
One adult kochia plant can produce up to 30,000 seeds.
Those seeds can initiate germination in as little as two or three hours.1
Early Weed Control Is Key
Because of that fast germination, kochia is difficult to control and can be very damaging to crops like corn and soybeans. In some cases, the weed can cause up to 70% yield loss.1
This means early weed control is key to keeping kochia at bay. A well-rounded program approach that includes several modes of action and extended residual activity can help manage herbicide resistance.
In corn, you can use Starane® Ultra herbicide as a burndown, followed by a preemergence application of SureStart® II herbicide and then a timely postemergence application of Resicore® herbicide. You’ll want to make sure to apply the postemergence before kochia gets any taller than 4 inches. Once it grows taller, it becomes ncreasingly more difficult to control with herbicides. (And, it should be noted, the weed can reach about 6 feet tall with roots extending 15 feet deep.1)
Crop rotation is another method that can help with kochia. Winter wheat is a particularly good choice to add into the mix.1
If kochia is a problem in your area, be sure to keep your eyes peeled for it during scouting this season. If any escape your control measures, it’s a good idea to hand-pull them to prevent them from flowering and producing more seeds.
This is one weed you don’t want to let get ahead of you. Just like the early bird getting that worm, the early farmer gets the upper hand on kochia.
1United Soybean Board. 2021. Kochia. https://iwilltakeaction.com/weed/kochia
Realm® Q, Resicore®, Starane Ultra® and SureStart® II are not registered for sale or use in all states. Resicore and SureStart II are not available for sale, distribution or use in Nassau and Suffolk counties in the state of New York. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Always read and follow label directions.
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