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Kaylene McNabb of Manly has come up with her own design for a guava moth trap, utilising a cheap solar light from The Warehouse and a recycled bottle with cooking oil in it.
Kaylene McNabb and Jim Watson of Manly have a fruitful orchard in their back garden that includes feijoas, macadamias, lemons, oranges, apples, grapefruit, plums and peaches.
This season most of the fruit – and the macadamia nuts – have had to be left on the ground because of infestation with guava moth. Fruit drop before they ripen and Kaylene and Jim say it’s heartbreaking to see it rotting on the ground.
It’s a problem that is being repeated all over the Hibiscus Coast, with gardeners from Army Bay right through to Red Beach reporting major loss (90 percent or more) of their feijoa and citrus crops.
Kaylene and Jim say last winter some of their fruit was affected, but this year it’s a lot worse.
In particular they are devastated that this year’s apples from a tree that they’ve had for more than 20 years are inedible for the first time.
“A bit of codlin moth isn’t a problem, because you can still eat the fruit, but this moth is a whole different story,” Jim says. “MPI should have tackled it from the start. It’s as bad as fruit fly. Why was nothing done?”
Guava moth is an Australian pest that was first found in NZ in the late 1990s. It spread throughout Northland, Auckland and into the Waikato. It attacks many varieties of fruit and nuts, year round.
Part of the reason that the pest can spread so quickly in an area is that there are few effective ways of controlling it and MPI says that total eradication was never an option.
“At the time of its first detection in New Zealand, MAF (the former MPI) carried out surveillance to determine how well distributed this species was,” an MPI spokesperson says. “It was found to be widespread. This, coupled with the presence of numerous different host species (both in domestic cultivation and growing wild) meant that eradication was not feasible. In addition it was determined that the introduction was likely to have been by wind dispersal from Australia and that New Zealand was very likely to be further exposed to re-infestation in the future.”
MPI suggests wrapping immature, green fruit with a fine weave mesh (such as frost cloth) to prevent the pest laying eggs on fruit. Fallen fruit should be raked up and removed or buried to kill pupating guava moths.
Some residents, Kaylene included, are trying DIY moth traps, with some success. These are based on a design by retired teacher Harvey Gadd who fixed inexpensive solar lights to a trap. The lights lure the moths inside, where they make contact with a little cooking oil poured into the base, get stuck and die.
Mike Weston of Gulf Harbour has also found the Aquaticus range of bug repellents (including Supernatural Glow and a pink fluid that acts as a sticker) effective in reducing the infestation of his plums and citrus fruit (HM March 2).
Local hardware stores, including Bunnings, sell a guava moth sticky trap laced with pheromones. Bunnings’ version costs $29.93 for the trap and $26.85 per refill. The moths are attracted to the sticky strips by the pheromone.
Guava moth is a small, speckled, inconspicuous moth with a 15mm wingspan. It lays its eggs on the surface of the fruit and the caterpillar, which grows to 5–7mm long, burrows in. Moth, larvae and egg photos, Plant and Food Research.
Hibiscus Matters opened a can of worms – or should that be guava moth lavae – with our story about guava moth on the Coast (February 3 edition). The moth attacks a wide range of fruit, year-round and large amounts of feedback to this paper indicate that it is a huge issue in this season’s feijoas and citrus crops, among others.
Reports have been coming into our office thick and fast over the last couple of weeks as people cut into their fruit and find they’ve been ruined by the pest. Readers would like to connect with each other to discuss the issue and share information as they try various ways of fighting back. To connect with other gardeners and share advice, comment on this story.
