Want Better Insect and Disease Control? Start with Your Weeds

Weeds are in constant competition with crops for nutrients, water and sunlight. And that’s not all; weeds also can serve as hosts for harmful insects and holding areas for destructive plant diseases. Proactive weed control is an integral part of keeping insect and disease pressure at bay during critical growth stages.

Brad Burkhart, key account manager, Corteva Agriscience, offers insight into how to consider the relationship between weed control and insect/disease pressure.

“They’re all related, and to think that they are not is a mistake,” Burkhart said. “They all bridge to each other.”

Burkhart emphasizes the start clean, stay clean policy for fields. If growers focus on keeping fields clean, not only are they promoting a healthier, more productive plant, but they also will reduce the risk of infestation and disease.

Weeds create favorable conditions for insects by providing food, shelter and reproduction sites. Many insects will survive on weeds before moving into crops. Burkhart notes that field edges are often overlooked regarding weed control and can be a prime target for insects and the starting point of an infestation. Weeds also can act as bridges for insects between growing seasons.

“If you have winter annuals like henbit or marestail, the eggs can live on that plant and they’ll overwinter,” Burkhart said. “When they wake up in the spring, you’ll have problems.”

While weeds can intensify insect pressure, they also can contribute to another challenge: plant disease. Weeds often host pathogens and create conditions that are favorable to disease development.

“Infections happen from the ground up,” Burkhart said. “So, when you have weeds that overwinter, the inoculum can live there as well.”

Weeds can harbor diseases between crop cycles by acting as a host for the disease to survive. Thick weed populations can reduce airflow, which can encourage plant infections. 

“If you have a big weed population, you’re not going to have the necessary airflow in the canopy,” Burkhart said. “You’re creating a microcosm environment where those pathogens thrive, which is going to make the spores germinate and cause a problem.”

Early control of weeds is key to reducing pressure from insects and disease. Using products with residual weed control and layering residuals can help strengthen the barrier for insect and disease pressure.

“You may be thinking to yourself: I’m saving myself into prosperity,” Burkhart said. “The reality is then you’re putting 10 things in a post-tank mix. You’re spraying weeds that are bigger, that are going to be harder to control.”

Crop rotation is also vital in breaking the weed-insect-disease cycle.

“We can use different tools in alternating crops, and by breaking the rotation, we’re not allowing the same hosts in those fields,” Burkhart said. “Using different modes of action prevents weeds and diseases from spreading, so it’s all interconnected.”

A proactive weed control plan should be used as a tool in a broader crop protection strategy. Weeds, insects and plant disease are considered as part of a grower’s program approach to producing healthier, more-productive crops.

“If you pencil things out and have a plan up front, you’re going to be less likely to change that plan, versus in heat of the moment when you’ll inherently either spend more or cost yourself more,” Burkhart said.

To learn more about crop protection solutions from Corteva Agriscience, visit Corteva.com/us.

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Want Better Insect and Disease Control? Start with Your Weeds

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