HONSHU WHITE ADMIRAL BUTTERFLIES
THESE HAVE BEEN RELEASED in the Waikato region to combat Japanese honeysuckle, a fast-spreading, white-flowered vine. The weed has become a huge problem in New Zealand with nothing to keep it in check as it grows incredibly fast - up to 15m a year - smothering bush and trees. It’s then very hard to kill with herbicides without killing whatever it is climbing on.
It is the caterpillar stage that feeds on the weed so scientists will have to wait to see if the butterflies (which don’t like mating in captivity) build up a big enough population to be effective. Landcare Research scientist Quentin Paynter says the caterpillars were voracious and each could consume several leaves during the course of its development.
“At the moment we are keeping a close eye on the initial release site. Because we have so few butterflies to play with, concentrating on getting establishment at one initial site may be the best option. But if we start finding large numbers of eggs at the first release site we will certainly consider releasing adults at a second site.”
He says they expect the butterflies to do well in New Zealand as the climate is less extreme than in their native Japan.
The Environmental Protection Authority approved the release of the butterfly in August 2013 after research showed the larvae would not feed on other plants.
YERSINIA ENTOMOPHAGA
AGRESEARCH HAS MADE steps towards using an insecticidal bacterium to control a native moth wreaking havoc on plantain crops.
The relatively recent appearance of Scopula rubraria and another similar moth ( Epyaxa rosearia) in large numbers in plantain crops has given rise to the commonly used name ‘plantain moth’. Last year, farmers in the North Island reported up to 90% of their crops being attacked by the moth’s larvae.
Plantain is a drought-tolerant, highprotein plant that is especially important for fattening up sheep.
Agresearch scientist Dr Mark Hurst says laboratory test spraying with a naturallyoccurring bacterium, Yersinia entomophaga, showed it could knock back the moth larvae by as much as 90% in just a week.