When Kevin Rice came to the University of Missouri in January, one of the first things he did was hand out a survey to farmers and producers across the state to gauge what insect issues they were dealing with on a regular basis.
His inquiries returned two main pests – Japanese beetles and stinkbugs. Rice has devoted a good portion of his research efforts to find ways to help those same farmers and producers battle the Japanese beetle.
“Japanese beetles are invasive species,” Rice said. “They have few natural enemies, and they are creating a lot of damage right now in multiple field crops.”
Rice said that Japanese beetles were first detected on the east coast about 100 years ago. They have been working their way across the country during that time, and arrived in Missouri 10 years ago. The population is now much more established throughout the state.
“We’re at the beginning of the invasive front,” Rice said. “Right now, there are higher populations in Missouri than Pennsylvania, for example, because several parasitoids from Asia were released in the eastern U.S., and they help reduce the beetle population. One of those parasitoids was recently discovered in Missouri.”
The Japanese beetle population is here to stay, Rice added. An attempt at eradication was tried after its initial discovery in the early 1900s and failed.
Japanese beetles feed on more than 300 species of plants, including field crops.
“Japanese beetles have a high dispersal capacity, meaning they feed on trees one day, move to vegetables the next, and so on and so on,” Rice said. “If you spray your crops on a Monday, you might kill 100 percent of the Japanese beetles. The problem is that by Thursday, there are more moving into your fields.”
Because of the dispersal capacity, Rice said there can be a temptation to continually use pesticides to fight off the invasive pest. Rice cautions against that thought.
“First, using that much pesticide is an extra cost to the farmer or producer,” Rice said. “Second, the pesticide could kill beneficial pollinators and other natural enemies, creating secondary pest outbreaks, such as stinkbugs.”
Rice and his team are researching more cost-effective ways of controlling the Japanese beetle population. They are using insecticide-impregnated nets, similar to the ones used in Africa for malaria. Rice has taken four-meter sections of the nets and placed them throughout the borders of crops at the Bradford Research Center, in Columbia.
“We have hung pheromone lures on the nets that are specific to Japanese beetles,” Rice said. “Previous research has shown that when the beetle lands on the net for just three seconds, it receives a toxic dose and dies. It has held true for us. We have mounds of beetles at the bottom of all of our nets.”
Rice’s team is currently going through data related to their use of the nets.
“There are a ton of questions that need to be answered,” Rice said. “How many nets do you need around your farm? How far away from your crops should you put the nets? Will the lures attract other insects? There is no silver bullet for this, so it’s important to cover as much as we can.”
Rice’s team will be using florescent powder next year to do more in-depth research. The team will place the pheromone in the middle of the field and mark the beetles with different colors, for example, pink at 10 meters, white at 20 meters and green at 30 meters. The study will give a plume radius of the pheromone and help the team determine what spacing works the best.
“We still have a lot of work to do and this is very much in the research stage at this point,” Rice said. “We’re only doing the work on research-specific fields at Bradford.”