by Kings Plant Barn’s online plant doctor Lee Gutzewitz
Spring is when the notorious Gauva moth starts targeting feijoas and citrus trees, among many others.
Guava moth is a small moth with the wingspan of approximately 15mm. Originally from Australia, it was first found in Northland in 1997. Since then the Guava moth has slowly been making its way south and over the last few years we are starting to feel the effects of this persistent pest.
At the time of its first detection in New Zealand, MPI decided that the pest was already so widespread that eradication was not feasible.
Hibiscus Matters ran a series of stories about it in 2016, when its impact was being felt here by home gardeners for the first time.
The moths lay their eggs on a wide range of fruit and nuts including guava, feijoa, citrus, apples, peaches, pears, plums and peppers. After hatching, the worm burrows into and spoils the fruit as it develops.
This moth is sometimes confused with codling moth as the damage is similar with a small pin-sized hole in the flesh of the fruit. However, unlike codling moth, guava moth can breed all year round. Signs to look for include premature fruit drop, exit holes or slight discolouration, bruising and, at later stages, the larva’s excrement may be visible.
Here are some tips on preventing attacks, and treating plants if they are targeted:
Prevention: Guava moth has the potential to cause a lot of damage and prevention is always the best way to stop this pest from destroying home orchards. • Prevent the moth from laying eggs on the fruit by draping bug netting over the tree and pinning to the ground or alternatively cut the net into sections and wrap around the fruit. Do this once flowering has finished to make sure your fruit is pollinated.• Ideally, coordinate your prevention efforts with neighbours to help avoid the build-up of severe infestations.
Treatment options: Though methods of control are somewhat limited, using multiple treatment options together gives the best results. • For monitoring or removing low level infestations use a guava moth trap that contains pheromone scent, which will attract and trap male guava moths. Other guava moth traps use lights which also attract other types of moths including female guava moths and the codling moth, which then get stuck to a small amount of oil underneath the light. • If you are catching five or more in a trap in a two week period, spray neem oil twice a week on and around fruit until you stop catching moths.