Hawaiʻi Island fight against invasive two-lined spittlebug heads to the Legislature
Spittlebugs feed on pasture grasses and have already caused the loss of thousands of acres of ranch land on the west side. It could impact food security as pasturelands become unusable.
Carolyn Auweloa, a state rangeland management specialist under the U.S. Department of Agriculture, said the spittlebug poses a serious threat.
"By the end of the first year that the spittlebug gets on a place, we’ve seen pastures lose nearly 100% of their forage capability," she said. "The plant community transforms from what was productive nutritious grass and clover pastures, to a forest of weeds."
The adult spittlebugs suck juices out of the grass and inject amylase through their saliva, she said. The amylase then interferes with photosynthesis, which can eventually kill the grass.
"It gets overwhelmed very quickly with weeds that cattle cannot eat and live on, and it changes that landscape. That’s where the problem starts," Auweloa told HPR's The Conversation.
She said the first spittlebug was found by ranchers in 2016 in the Kona area.
"Since then, a lot of work has been put into trying to understand the extent of the damage, how it's been spreading, what the biology of this bug is in Hawaiʻi — and how it's impacting our pastures and how we might try to deal with it," she said.
Auweloa estimated that it could cost a rancher $500 per acre, and up to 10 years to re-pasture land impacted by spittlebugs.
Nicole Galase of the Cattleman’s Council represents cattle farmers on the Big Island. She said this is going to be one of the biggest detrimental impacts to the cattle industry in our lifetime.
"The ranchers that have the two-lined spittlebug, they are there working on making sure they have enough forage for their cattle. They're spending lots of money out of pocket, trying to reseed those pastures to make sure that there's no bare soil. They're combating the weeds that come up once the bare soil allows for those weeds," Galase said. "It's a tough battle and the ranchers are at the forefront of this."
Unfortunately, Auweloa said eradication of the spittlebug may not be possible.
"This little bug is on almost 200,000 acres, and to be able to try to wipe it all out — it's just not logically, not really possible," she said.
But efforts continue to help farmers respond to the landscape changes, such as choosing resistant grasses. Auweloa said pesticides are not a feasible alternative for such a large acreage.
If you see this species, call 643-PEST or visit 643pest.org. To mark Hawaiʻi Invasive Species Awareness Month, The Conversation will have updates throughout February on the battle against invasive species across this state. This interview aired on The Conversation on Feb. 22, 2022. The Conversation airs weekdays at 11 a.m. on HPR-1.