Dr. M. O. Way and Dr. Thomas A. (Gene) Reagan have no formal war training, but like generals on a battlefield of rice and sugarcane, they do their best to delay the advance of a silent enemy that’s slowly working its way east across Texas and now threatens Louisiana rice and sugarcane crops with the potential for annual losses of more than $250 million.
Way, Professor of Entomology, Texas A&M AgriLife Research and Extension Center at Beaumont, and Reagan, Austin C. Thompson Endowed Professor of Entomology, Louisiana State University Agricultural Center, have teamed up to develop a strategy for limiting the growing threat of stem borers, including the recent introduction of the Mexican rice borer (MRB), a pest that has historically damaged sugarcane crops in South Texas and continues to pose a significant problem for Gulf Coast rice farmers in Texas and western Louisiana.
Recently the two hosted a field research site visit at the Texas AgriLife Research Center in Beaumont for Texas and Louisiana sugarcane and rice consultants, agricultural Extension agents, and industry cooperators. The field day was designed to share the results of 11 years of comprehensive research and strategies developed to prosecute the fight against the deadly pest. Entomologists warn the aggressive Mexican rice borer also poses a serious threat to other commercial crops like corn and sorghum.
“This particular pest nearly destroyed the Rio Grande Valley sugar crop back in the 80s and worked its way up the Texas coastline to invade Southeast Texas and now is into five Louisiana parishes, and it’s finding suitable feeding grounds on a number of commercial crops including sugarcane, rice, corn, and sorghum, as well as native grasses,” says Reagan. “The Mexican rice borer is the most destructive insect pest of sugarcane in North America and has the potential of causing as much as a 50 percent yield loss in Texas rice fields.”
Not a simple fight
Thanks to their dedication to the war effort and supported by a number of national competitive grants, Way and Reagan’s work is paying off. By researching the borers and discovering the particulars of their biology, ecology, life cycle, habits and mode of operation, the two entomologists are getting a handle on the best way to fight them.
“It’s not a simple fight,” Way says. “When the moth lays eggs on a plant and they hatch, in some instances there is a window of 24 hours or less before the larvae bore into the stalk and become protected from chemical treatment, so a much broader strategy had to be developed to be effective.”
That strategy involves knowing precisely when a field becomes a breeding ground, which can only be accomplished using a comprehensive pheromone trap assisted program.
“The fight against these borers doesn’t stop here. We have developed a good program involving cultural controls, insecticidal tools, trapping and observation, and development of resistant cultivars, and I think we are on the right road to help minimize the risks of MRB damages in commercial crops,” adds Way.
Another interesting tool the researchers used to fight the pests involved a study to assess the effect predation by the red imported fire ant has on MRB injury to sugarcane. These natural predators are proving very effective in controlling borer populations in the field. Also, novaluron, a chitin synthesis inhibitor, has proven successful in treatment of MRB in sugarcane, and another biorational insecticide, tebufenozide, has provided promising results.
According to Way and Reagan’s site visit report, during ten years of collaboration, the project has been responsible for identifying resistant varieties, developing sampling approaches to monitor infestations and quantify pest populations, and evaluating and helping label environmentally friendly insecticides.
“With colleagues, we have studied numerous plant/insect interactions involving crop and non-crop host preferences, and better defined the role of plant stress impacted by cultural practices, salt, water and nutrients,” the entomologists write in their report.
According to the report, with recently labeled insecticides having four different modes of action -- (Confirm, Diamond, Coragen/ Belt, Besiege), the potential for insecticide resistance is reduced. In rice, a newly developed seed treatment, Dermacor X-100, impacts stem borer management in addition to pyrethroid foliar applications.
“What started as a reactive approach to a developing problem has become a better planned fight against what we now know is a growing problem,” adds Reagan, and this, he says, is what has given the entomological warriors an advantage in their war on boring insects of the Gulf Coast region.