Coscinoptycha improbana (Guava moth)
Species: C. improbana
Binomial name: Coscinoptycha improbana
Common name: Guava moth, Feijoa moth, Australian guava moth,
Coscinoptycha improbana (Guava moth) is a small, black and white speckled, inconspicuous moth with a 15mm wingspan. It is native to Australia. It also occurs on New Caledonia, Norfolk Island and it was first recorded in New Zealand in 1997 in Northland and by 2016 it has spread as far south as the Waikato. It is said that it is killed by frost but it will still become a real pest in frost free areas.
Guava moths attacks a large range of fruit and nut trees, feijoa (Acca sellowiana), loquat (Eriobotyra japonica), guava (Psidium sp.), macadamia (Macadamia integrifolia), plum (Prunus domestica), peach (Prunus persicae), apples (Malus domestica) pear (Pyrus sp.) and citrus (Citrus sp.). The loquat (Eriobotrya japonica) is its favourite host and all wild plants should be removed.
The Guava moth is a problem moth because it is on the wing all year round and can infect trees in all seasons. It lays its eggs on the surface of the fruit and the young caterpillar makes a tiny hole in the fruit’s skin as it burrows inside, directly below its egg. Once inside the damage is often difficult to spot until the fully-grown caterpillar chews its way out. Sometimes the outside of infected fruit can have circular brown patches and excreta (frass) can extrude from infested fruit and nuts. The feeding caterpillars leaves rotting, brown patches, excreta and mould inside the fruit, making the fruit inedible and causing early dropping of unripened fruit. The caterpillar is pinkish and grows to 5-7mm in length.
This moth is very difficult to control. Some controls suggested are, if possible cover the tree with a mesh cloth and tape tight to prevent moths laying eggs on fruit. This of course is impossible with large trees.
Remove fallen and rotting fruit and associated leaf litter from beneath trees and bury or burn it. This will destroy pupating guava moths.
Guava moth pheromone delta traps with sticky bases are available from garden centres and rural suppliers.
There are no insecticides registered for use against guava moth and due to the wide range of fruit crops affected by guava moth it means no single product or product group can be recommended for insecticide control.
For more control information visit: http://envirolink.govt.nz/PageFiles/436/611-nlrc84.pdf
Another site publish early 2016 about the moths effects on Northland growers. http://www.localmatters.co.nz/News/Hibiscus+News/April+2016/Guava+moths+grip+on+communitys+crops+grows.html
The Guava moth's larva
The caterpilars small entrance hole in a feijoa.