Cotton Links


Thrips Control Helps Root

By Amanda Huber
Southeast Editor

Rapid, early season root growth is critical to the health of a young cotton plant. A vigorously growing root system means the plant is more likely to withstand nematode damage and reach a stage where seedling diseases have less impact more quickly.

Reducing thrips injury to the foliar part of the plant is necessary to promote maximum root growth. Overall, researchers say producers should keep in mind that what is happening above ground is happening below ground.

It’s All Relative

“We have been exploring the relationship of early season thrips injury on root development for a couple of years now,” says Philip Roberts, University of Georgia Extension entomologist for cotton. “There is a strong correlation of above-ground plant growth and root growth.

“When you have excessive thrips injury, and the above-ground plant growth is stunted, the root growth is also reduced.”

In Georgia, he says most producers put out a preventative insecticide application at planting.

“But,” he says, “we still need to scout those fields for thrips. If we have heavy pressure, we will find damage sufficient that a foliar spray is needed.”

Roberts says classic thrips damage is crinkling of leaves and possible stunting of the plants.

“The bottom line is that what you see above the ground, as in plant stunting, you will get that same stunting below ground,” he says. “Poor root growth interrupts so many other plant functions, such as the plant’s ability to deal with drought stress.”

Therefore, rapid, early season root growth depends on good management of thrips early on, and rapid, vigorous root growth also is very important in nematode management.

Vigorous Roots Are Important

Nematode damage is likely to happen, says Bob Kemerait, University of Georgia Extension pathologist.

“The key is to have the roots grown enough to be well established,” he says. “The more established the root system is, then, even when damage does occur to them, the roots are more able to tolerate that damage.”

The Georgia pathologist says nematodes are stress multipliers.

“They will make any stress worse,” Kemerait adds.

A cotton seedling that is working to overcome thrips damage will not have vigorously growing roots. The poorly growing roots will succumb to nematode damage more than vigorously growing roots, and this scenario will reduce the plant’s ability to overcome disease pressure.

“A vigorous, rapidly growing plant is going to reach the level of maturity where a fungus has less ability to affect it,” Kemerait says. “The more you can do to get rapid emergence, rapid growth, the better the plant is able to outgrow disease.”

Vigorous, rapid root growth is the key, and thrips control is important to achieve that growth.

“Thrips are extremely predictable in cotton,” Roberts says. “We’re not saying that you need to go out and spray for thrips, but you don’t want to overlook them either.”

Scouting is the main idea, he says.

Contact Amanda Huber at (352) 486-7006 or ahuber@onegrower.com.

Why Is Thrips Control Crucial?

• Thrips attack plant roots.

• Serious effect on plant growth.

• Impact on maturity.

• Susceptibility to disease.

• Affects plant emergence.

Return To Top