Researchers are asking for the public’s assistance in preventing the spread of an invasive insect destroying grasses in West Hawaii. The Twolined Spittle Bug (TLSB) was discovered in Kona late 2016, when a rancher in upper-elevation Hualalai first reported widespread die-off of pastures. Initial surveys found nearly 2000 acres were already affected. If you see the insect or suspect TLSB damage, please report to 643pest.org.
SUMMER 2020 SURVEYS
A threat to our food security and Big Island economy
Surveys in the summer of 2020 revealed that TLSB has impacted more than 175,000 acres of rangeland from South Kona to Pu’u Wa’awa’a near Pu’uanahulu. The TLSB is consuming Big Island pasture at a rate of about 35,000 acres per year. Spittlebugs feed by sucking nutrients and fluids from the plant stem, weakening and potentially killing the grass. Although Hawaii already has introduced spittlebugs present, none have had such severe impacts. Like many invasive pests that arrive in Hawaii, the new bug, a native of the southeastern US, was likely brought in accidentally on imported plant materials. Now, it is attacking kikuyu and pangola grasses: critical forage that support nearly 70% of Hawaii’s beef cattle industry.
To make matters worse, grasses in open lands prevent difficult and impactful weeds from moving in. Where TLSB has killed off the grass, invasive plant pests like pamakani, fireweed, and wild blackberry, long battled by ranchers and farmers, have begun to take over. The loss of grass and surge of weeds have been devastating to upper elevation pastures in Kona, which have not recovered from the damage.
Researchers are extremely worried that the spittlebug could be transported to the iconic pastures of Kohala and Hamakua. Kikuyu grass is the primary forage in many of these places, and a TLSB introduction could devastate the cattle industry and significantly change the character of the landscape.
Threat to watersheds and forests
These new invading weeds also threaten native restoration efforts, which seek to return grass back to native forest. Brushy species prevent establishment of native seedlings, and are exponentially more expensive to control than grass. Increased propagule generation from thousands more acres of invasive weeds increases the effort needed to keep weeds out of intact or restored native forests.
What to do
Big Island residents are being asked to be alert about their lawns and pastures – patches of dead grass that cannot be explained by other environmental factors should be reported right away. As always, it is best practice on Hawaii Island to avoid movement of potted plants or live plant materials into new areas. Fire ants, ROD fungus, coqui eggs, and many other pests have traveled quickly and spread, on- and off-island, through this route. The spittle bug, very tiny in its nymph form, can easily attach to a plant stem without notice. Those who may visit Kona pastures or other areas impacted by TLSB– like hunters or ranch workers – should carefully clean their vehicles and equipment of any mud by washing out wheel wells and tires before traveling to other districts on the island.
Be familiar with the insect and if you see one, trap it and report it to 643pest.org. Early detection is critical in containing the spread of this pest!
Research and outreach efforts are being led by Mark Thorne, Range & Livestock Management specialist for the University of Hawaii extension service (CTAHR), firstname.lastname@example.org or 808-887-6183, and Carolyn Wong, USDA NRCS Grazing Land Management specialist, at Carolyn.email@example.com or 808-885-6602 (ext 105). If you are a rancher impacted by TLSB, please contact them for assistance. More resources can be found on the Hawaii Rangelands page and at TLSBhawaii.com.
Download CTAHR Alert Nov 2018: CTAHR bulletin
Download CTAHR Alert Mar 2017: Spittle Bug Alert March 2017 ver 5. (Final)