If your fruit crop is in the northern rivers of NSW it may have been attacked by giant Fruit Piercing Moths this summer. If you are north of Brisbane (anywhere in the tropics) there is a greater chance; in fact the reason I’m writing about Fruit Piercing Moths for the first time, is because Richard Henderson from Kin Kin (inland from Noosa toward Gympie) lost all his fruit this summer. To quote him: 

“I have again been smashed by the moths, killing 100’s again every night, large R2E2 mangos and you can’t see the fruit for moths. In the week they took to ripen more, the moths came in and destroyed every fruit.  I got to eat one fruit from a tree that would have had over 100 fruit on. It was looking like a great year for mangos… till now.  On just one mango, I crushed 8 moths and still more flew away. I can tell which mangos they have been feeding on; you can smell the difference in the mango juice when squashed. I can see on the ground if there is a fruit above being sucked, there is stuff they squirt out all over the ground, 10-15 moths squirt a lot of juice. I will do some sprays this weekend just to give me some satisfaction in killing the bastards. 

“I did read on-line that the moths can travel up to 20km in a night, they are very strong fliers.”  

Another email: 

“I got knocked down with covid for a bit over a week. When well enough to do a spray… there was no fruit!  
Trees full of Keitt and Palmer mangos… all gone in a week ( best crop of Keitt I have ever had).  

“They are even starting on citrus that isn’t much bigger than golf balls and custard apples that are still smaller than your fist. I wouldn’t have thought fruit like this would have had any juice to suck. I can clear a tree of moths and then 30minutes later they are back in the same numbers. I either have to forget about any fruit growing for sale and just net some trees for me, or I will have to prune all trees for protection coverings.”  

So what are these Fruit Piercing Moths?  

Big! Very big.  About 100mm (4 inches) across. Just a few species in Oz. 

They’ve migrated from tropical countries and they like any fruit grown in their backyard… and their backyard is getting bigger! 

 The forewings are brownish often with some green and cream flecks; the hindwings are almost beautiful… I think Richard sees orange wings with black spots more as a target. 

 Moths and butterflies in general have a proboscis of the roll-out-to-reach-down-to-the-nectar-inside-flowers type. Not these brutes; they have a ‘weapon’ that is almost rigid and enough strength and weight to force it through the skins of mango and custard apple fruit. As described above, they can penetrate hard, immature citrus fruit that hasn’t even become juicy. 

Their caterpillars do not eat the leaves of the fruit tree; they prefer native vines of the family Menispermaceae (about 20 species in northern Australia) and sometimes coral trees. 

I couldn’t find a reference to how many eggs are laid, however the females ravenously consume large quantities of sweet juices that logically ought to be converted into hundreds of eggs. 

The orange and black larvae go through their 5-6 moults in 3-4 weeks on the way to being as big as your finger. 

There are three pair of legs on the thorax just behind the head and four sets of prolegs down the other end. There are two sets of white spots on the gap between the sets of legs. They move in undulation style like loopers. 

You may never see them if the host vines are not on your plot. 

After the weeks of feeding, the larvae spin a cocoon usually between a couple of leaves so they are less visible. 

After another couple of weeks in the cocoon they emerge ready to sniff the breezes to get a bearing on your tropical crops of lychee, mango, carambola, banana, custard apple, papaya, citrus, fig, persimmon, guava, kiwifruit… and others. 

There appears to be no end to their talent for devastation. 

With a wingspan of around 150mm (6 inches) flying at night is less noticeable and safer from preying birds. With wings that substantial it’s no wonder they can travel long distances. 

Control 

Richard again: 

“I don’t think even a trap that actually worked would be able to handle the volume of these pests. Anyway, the squash racket is getting plenty of use now as well. You wouldn’t think a moth would break racket strings, but they do; a very tuff customer indeed.” 

Apart from a squash racquet which is only so much fun, green tree frogs can chip in to help. 

See the almost famous photo from Richard of the frog pausing to contemplate how it is going to try and gulp the rest of the moth down. 

As there are many more moths than nearby treefrogs, you need other options. Birds don’t seem to be contributing in this war; night-flying moths are seldom seen by sleeping birds. 

I don’t see Fruit Piercing Moths listed among the parasites and predators listed in the advertising by Bugs for Bugs or Biological Resources, but sure, there would be some wasps that take some toll on  their larvae…way back there in the vines undergrowth. 

A physical barrier is an option. From Richard again: 

“I was at a solar job yesterday and there’s a persimmon farm next door. I was talking to the manager and they have needed to net trees for several years now due mainly to the moth. They export persimmons and netting was their only solution. They use exclusion netting as it keeps out the fruit fly as well, but he said the biggest issue for them was the moth.” 

As is often the case, it is so good to have Py-Bo ready in your shed. 

Richard adds a bit of washing-up detergent to his spray pack so that there is easier penetration and wetting of the scaley/powdery moth surfaces. 

He can see where to aim by the myriad red eye reflections sparkling in the torch light. The same goes for you if you use tractor headlights. 

The natural pyrethrum insecticide will kill, even if you only hit their heads/antennae. There are few protective scales around the eyes and mouthparts and if you also wet the fruit they are sucking, solution will run down and penetrate the joints in their feet. 

They are big buggers; it will take a few minutes to generate the excitation response which causes them to fly off. 

Pyrethrum induces four stages of response: excitation, spasms, paralysis, then death. 

The arousal/excitation causes them to fly… and they may be well away from the crop before they spasm and fall to ground. 

Birds and rodents  are likely to eat the fleshy bits next morning and the wings will be hardly differentiated from dead leaves.  

You may have to do the spraying a couple of nights in a row… just check for red eyes before you load up.