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Nun moth a threat to Pinus radiata

Scion is the leading provider of forest-related knowledge in New Zealand
Formerly known as the Forest Research Institute, Scion has been a leader in research relating to forest health for over 50 years. The Rotorua-based Crown Research Institute continues to provide science that will protect all forests from damage caused by insect pests, pathogens and weeds. The information presented below arises from these research activities.

From Forest Health News

I recently returned from a 10 week fellowship with the USDA Forest Service funded by UNESCO (the United Nations Educational, Scientific, and Cultural Organisation). The research undertaken was an example of Forest Research's pro-active research programme into identifying potential pests of Pinus radiata from overseas. Until now, the ability of both the lymantriid forest defoliators, nun moth (Lymantria monacha) and gypsy moth (Lymantria dispar) to utilise and complete development on P. radiata had not been established in laboratory trials. The nun moth is considered a potential pest as it is a conifer-feeding specialist. It is also much more difficult to detect at the border than gypsy moth as the females lay eggs deep within crevices on containers, pallets, and ships. Adult nun moths are attracted to lights, as are gypsy moths, and have been observed in port facilities in the Russian Far East. In Connecticut I had access to colonies of a central European strain of nun moth and a Russian strain of gypsy moth held in a USDA quarantine facility. Foliage from New Zealand breeding lines of P. radiata (GF 22 or better; advanced selections based on growth and wood properties) for use in the feeding trials was obtained from stands in California.

The results showed both the nun moth and the gypsy moth were capable of completing their development through to adults on New Zealand breeding lines of P. radiata. Pinus radiata was a poor host for gypsy moth development and neonate larvae were initially very reluctant to feed. Nun moth developed much faster and showed better survival on P. radiata than it did on another suitable conifer species, Picea glauca.

The nun moth showed moderate growth rates and survival on P. radiata. Neonate larvae did not require flushing foliage or male cones or buds to be present and fed quite happily on mature pine needles. This suggests the impact of establishment of nun moth in New Zealand could be severe. Based on this knowledge it would seem prudent to establish a nun moth incursion detection programme around risk sites in New Zealand using the commercially available pheromone "monacha-lure". Or alternatively to return to the use of racemic disparture, as used initially in the New Zealand gypsy moth trapping programme, as this attracts both gypsy and nun moths.

Toni Withers, Forest Research

This information is intended for general interest only. It is not intended to be a substitute for specific specialist advice on any matter and should not be relied on for that purpose. Scion will not be liable for any direct, indirect, incidental, special, consequential or exemplary damages, loss of profits, or any other intangible losses that result from using the information provided on this site.
(Scion is the trading name of the New Zealand Forest Research Institute Limited.)


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