Sugarcane Aphids Heading North

It's been 80 years since the Midwest has experienced a pest problem like it may experience this year.  The sugarcane aphid has mostly been in Texas along the gulf coast and Louisiana.  However, they appear to be heading north.

What does a sugarcane aphid do?  They can damage a plant in numerous ways.  They can thin out a sorghum plant until it reaches reproductive stage.  The aphid then chews on the panicles, resulting in decreased grain weight and a loss in yields.  Aphids also secrete honeydew which covers the mature plant causing a sticky and messy harvest.

Mike Brewer, field crops entomologist with Texas A&M AgriLife in Corpus Christi, says in an article by Agriculture.com damage from sugarcane aphids on sorghum plants topped $50 million in damages last year.  As they spread that damage will only get worse.

"I think it is a good expectation that severity would increase.  The worst case scenario is that up to 50% of fields could be infected.  Assume 50% yield loss, based on what we know from earlier aphid infestations, and we could have $400 million economic loss statewide," Brewer said at a meeting in Corpus Christi in January.

Sugarcane aphids reproduce in the spring.  They are able to breed two to seven days after birth, laying as many as 20 nymphs per cycle.

Brewer said, "Within 6 weeks of the first winged aphid landing on the plants, you will see sooty mold and honeydew.  The plant begins giving out.  On the positive end it takes a lot of aphids before the plant succumbs to aphids sucking fluid out of the plant."

In an interview with Kansas State University's Radio Network, J.P. Michaud, Extension entomologist at K-State, says sugarcane aphids are expected to be in Kansas and Nebraska this year.  "We can be fairly sure we will have some migrants arrive here at some time, but we don't know how well they will survive," he says.

Michaud encourages sorghum growers to pay extra attention to their crop this year.  "They are noticeable because they have very short, black tailpipes on a very pale nymph," he explains.  "They colonize first on the underside of the lower leaves, and move up the plant as the leaves die.  It's a very similar feeding pattern to greenbugs."

There are no insecticides labled for sugarcane aphids on sorghum plants.  However, some exceptions have been made in Louisiana and Texas in extreme conditions.  

Michaud says lady beetles could help suppress that aphid infestation but that may take a few years.  "It may be advisable to leave small areas of fields unsprayed in order to let first responders evolve into natural control," he points out.