Since 2016, Mark Thorne and Mark Wright have waged war on the invasive Twoline Spittlebug. The invasive pest is devasting rangelands on the Big Island, which is a concern for both the Dept. of Human Nutrition, Food and Animal Sciences and the Dept. of Plant and Environmental Protection Sciences.
Recently, Mark T. was interviewed for a Hawaiʻi News Now segment featuring CTAHR’s efforts to contain the pest. A separate KHON2 report also showed images of the CTAHR research team doing field work.
“The best we can do to manage the spread, at this point, is to find ways to reduce the Twolined Spittlebug populations to levels below thresholds that inflict catastrophic damage on rangeland resources,” he says. “This should also help slow the spread of the pest into other areas that not yet affected by the pest.”
He adds, “Currently, our research has focused on understanding the biology and ecology of the pest on pastureland, carrying out host-plant resistance experiments on an array of forage grasses to determine which are susceptible or resistant to Twolined Spittlebug adult feeding. We’re also developing integrated Pest Management strategies, including intensive grazing management to reduce suitable feeding and egg laying habitat for adults and nymphs, coupled with strategic use of pesticides and revegetation with grasses resistant to Twolined Spittlebug feeding.”
Mark T. and Mark W. are also investigating an “entomopathogenic” fungus – indigenous to Hawaii – that may affect the spittlebugs. A few years back, they observed dead Twolined Spittlebug adults that had been infected by the fungus. They collected samples and sent them in for analysis.
“Since that time, we have observed an increased rate and a wider spatial occurrence of infection of Twolined Spittlebug adults from this fungus,” he says. “We are hopeful this naturally occurring biocontrol can help throttle down the population growth of the pest. Additionally, we are investigating ways that we may harvest and potentially domesticate the fungus for use as a commercial biocontrol.”