Transcript Document
Protecting Hawai‘i Pre-entry Port-of-entry Rapid-response (laws & agreements) (inspection) (response crews) World’s Biota Arrivals Escapes Widespread Options: -Do nothing -Protect high value areas -Biocontrol Biocontrol Projects in Hawai‘i • Protocol for biocontrol research and testing cannot be compared to the careless and unregulated introduction of mongooses in the 1880’s and cane toads in the 1930’s • Years are spent on controlled testing to see if the biocontrol species will switch hosts—if it does, it is NOT released Wasp proposed for control of nettle caterpillar • Example: Of the 51 biocontrols introduced since 1975, none have switched hosts to non-target species • None of the 51 biocontrols have become problems in their own right Problem: Wiliwili Gall Wasp • Small wasp native to Africa, discovered in Hawai‘i in April 2005 • Female inserts eggs into leaves, which makes the tree form “galls” around developing larvae Adult female on right is only 1.5 mm long • Kills native wiliwili, and “tall wiliwili”, and coral trees • Biocontrol is the only hope for suppressing the gall wasp and replanting the native wiliwili Biocontrol for Wiliwili Gall Wasp: Eurytoma • The Eurytoma wasp has been studied and tested as a biocontrol insect to help control the wiliwili gall wasp • The female Eurytoma deposits a single egg into the gall, from which a larva hatches Eurytoma for control of wiliwili gall wasp • The larva Eurytoma sucks the juice out of the gall wasp larva, then tunnels into next gall chamber and feeds again, etc. • The larva then pupates within the gall and the adult wasp emerges to reproduce • Testing has shown that the Eurytoma wasp does not switch hosts, and this biocontrol insect will be released this summer Problem: Stinging Nettle Caterpillar • Native to Asia, this inchlong, stinging caterpillar was first detected in a Hilo nursery in 2001; Oahu and Maui in 2007 •Caterpillars feed on more than 30 different plants such as ti, palms and grasses, causing leaf damage •Touching the spines causes a burning sensation, resulting in blisters or welts •Heavy infestations in some yards and nurseries; continue to be moved in plants Biocontrol for Stinging Nettle Caterpillar Aroplectrus dimerus •The wasp Aroplectrus dimerus, was found in Taiwan, where it keeps the caterpillar's presence to a barely noticeable level Wasp proposed for control of nettle caterpillar •The wasp deposits eggs on the underside of the nettle caterpillar. When larvae hatch, they feed on the caterpillar, then pupate and change into an adult •Host specificity testing is complete and the project is awaiting a final permit for release Problem: Strawberry guava •Small tree up to 20' tall introduced as an ornamental & fruit tree • Prolific seed producer; seeds spread by pigs, larger birds, possibly rodents •Forms dense stands, crowds & shades out native plants, keeps native plants from sprouting •Invading moist and wet forests on all islands. Produces 27% less surface & ground water than ohia forest •Chemical/mechanical removal not possible over 100’s of 1,000’s of infested forests Strawberry guava seedlings Biocontrol for Strawberry guava: Tectococcus ovatus •Nymphs feed on new leaf tissue, causing galls to form •Galls result in reduced plant vigor and a decrease in seed and fruit production •Tectococcus does not kill strawberry guava plants, it only makes it behave more like a normal plant, allowing native forest species a chance to compete Effect of Tectococcus: galls on leaves •In Brazil and in more than 15 years of testing (more than 80 species of native & non-native plants), it has not switched hosts. It needs strawberry guava to be able to survive. Biocontrol & You •Biocontrol isn’t a silver bullet. It is considered the last chance to restore some balance to nature, to reduce an invasive species’ impact on key resources or systems • Get involved. Learn about the problems and the proposed solutions & weigh all options carefully •Although Hawai‘i has a relatively long history of successful biocontrol (30+ years), many nations have been conducting successful projects for much longer, without unintended or adverse impacts to non-target species. •In Hawaiʻi, we have an additional step in the EA process: posting on the Hawai‘i Department of Health OEQC website for public comment