New Invasive Pest Continues To Be A Problem For Sugarcane As Harvest Begins

ANTHONY BAILEY

PORT ALLEN, LOUISIANA

 On a Monday morning at a sugarcane farm in Port Allen, LSU AgCenter entomologist Blake Wilson and two student workers pushed through green and yellow cane stalks on a field’s border and into the interior rows. There, they found plants that were completely brown.

This farm, and many others throughout the state, has been infested with the pasture mealybug, an invasive species first identified by Louisiana crop consultants last year. At this time of year, when harvest season has begun, most farmers would be excited for their crop to be sent to the sugar mills. But this year, growers aren’t sure what to expect from their product.

“Until we start getting well into the harvest season, it’s just hard to know how the pasture mealybug will affect yield in the field and recovery at the mills,” said Kenneth Gravois, AgCenter sugarcane specialist. “Data has been collected and will continue to be collected. Once the harvest starts, we’ll start collecting more data on the yield aspect of the problem.”

The pasture mealybug was found on five commercial farms around the state in 2025. This year it has been detected in every parish that grows sugar cane — most severely in West Baton Rouge, Iberia and Vermilion parishes.

The small, white pest was first found in Australia, where it damaged pastures and affected the cattle industry. AgCenter experts believe this is where the pasture mealybug came from before it ended up in Louisiana, but there is so little information on the pest that researchers are not sure if it is native to Australia. The insect has since infested cattle farms from Texas all the way down to El Salvador.

While experts did expect to see the PMB in Louisiana, it was a surprise to see it in sugar cane, and an even greater surprise with how aggressive it spread.

“Within two weeks, a farm can go from healthy to almost ruined,” Wilson said.

Right now, in Louisiana, researchers are trying to find an immediate solution to this serious problem. Insecticides have helped with control, but not as much as Wilson and other researchers would like and often required multiple applications. The insect gets on all levels of the plant, including the roots, and because the insecticides don’t kill the ones in the soil, reinfestation occurs within a couple of weeks.

One test being done is how effective a mixture of ripener with insecticide could improve the yield on farms that have been infested with the bug, but as with all experiments, results won’t be available until the season has ended.

Luckily, the AgCenter is not working on this project alone. The pest also has infested sugarcane farms in Florida, the only other state to grow sugarcane in the U.S., so Wilson and other AgCenter researchers have been in communication with sugarcane scientists from the Sunshine State.

Hannah Penn, a U.S. Department of Agriculture entomologist in Houma, has begun work to find a solution to the pasture mealybug. Sugarcane crop consultants and agronomists with the American Sugar Cane League have joined the research effort as well.

Wilson is in direct contact with researchers in Australia, as any new information can improve the increasingly stressful situation for all stakeholders dealing with the new bug.

Unless something changes, this problem won’t be going away soon, and Wilson said the AgCenter is already readying for another substantial year for the pasture mealybug.

"We're looking at quantifying the relationship between insects and yield loss. We've applied for some grants. Now we're trying to get some more money so we can be geared up to do a lot next year," Wilson said of their preparations for the upcoming season. "I think it's going to be worse. It went from five fields last year to more than 500 fields this year. I think next year it's going to be every single field. It's really kind of on fire."   ∆

ANTHONY BAILEY

LSU AGCENTER