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Matty May Hate Gophers, but.... I... hate... BANANA MOTHS!!!


Dr. George

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There is trouble in paradise.

The Big Island is having an increasing problem with banana moths, or at least the destructive, burrowing larvae (caterpillars) of this innocuous little brown moth. They are becoming increasing problematic for some agricultural crops, production of ornamentals, some landscape plants, and an endangered native Hawaiian plant.

Well, palms are on their menu, and if you live on the Big Island and have not had them pay you a visit, keep a watchful eye out as they will show up.

It is said that they prefer dead, decaying plant material, but that's just not true - they are just as happy in live tissue. Very commonly we'll find then set up housekeeping in a new spear - presumably the female moth lays eggs in the folds of the spear and the little buggers start munching away as soon as they hatch, first in the spear then down the inside of the rachis into the crown shaft.

Spear of a Lemur showing early damage. Caught this one in time and saved it before the caterpillars got very far down the spear.

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Here is a young Mauritiella armata that wasn't so lucky. You can see the nasty little bugger exposed from the base of the petiole where it has been happily munching away inside. All that brown granular looking stuff is not dirt, it's the signature frass of banana moth larvae (caterpillar poop).

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Here is a Neoveitchia storckii that wasn't so lucky. Still trying to save it, but the infestation was pretty advanced when we arrived for our Spring visit.

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The caterpillars could be found on the back sides of the boots

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And have been making their way down the leaves headed for the crown shaft.

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This Bentinckia condapanna wasn't so lucky.

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Once the caterpillars got into the crown they had a field day cleaning things out, then left their calling card in the form of a pupae casing as they headed out to the next banquet site.

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Even the inflorescence/infructesence are susceptible, at least they really like those of our D. leptocheilos. Backside where you can see that they have burrowed into the base of the structure where it was attached to the trunk.

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and you have to open it up to find them.

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They have a distinctive brown head, and brown strips across their backs as they mature.

They are difficult to control, because the caterpillars burrow into the plant making it hard for topically applied products to reach them, and once an infestation starts, there may not be enough time for a post infestation applied systemic to get to them before they've done their damage and moved on.

All of our palms have been receiving twice monthly spraying with Bacillus thuringiensis (Bt) and all of this occurred in spite of the Bt. So we are stepping up the game. State entomologist coming in to see if we can identify a source site. Pheromone traps, preventative imidacloprid drench to all, have and will be removing all inflorescence spikes before flowering, continued Bt and probably will rotate with another topical, and increased vigilance for early local treatment of infestations.

Hope you don't have to face down these. Love to hear of any magic bullets anyone else has found.

gmp

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The nematodes Steinernema carpocapsae would be very efficient killing these things in a solution together with Chitosan,poured at the growing points of the palms till all green leaf bases are filled with/drenched by ir,and also applied at the root initiation zone as this is considered a susceptible area of the palms for borers too. These should be very effective as they are very efficient at killing borers that affect palms like the Rhynchophorus ferrugineus and the Paysandisia archon with 98% death of all forms of the borers with each application,compared to just 50-70% of imidacloprid(varies depending on application method) and other chemical treatments.

Its worth looking around to find a formulation of these nematodes with chitosan but f you can't find a product and cant find info on how to make a formulation of these,I could help with quantities if you can get the raw materials :) And the best thing about them is that they are totally human and pet safe and even if you were to eat them and the Chitosan there would still not be any health concern!

''To try,is to risk failure.......To not try,is to guarantee it''

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Oh, that is really depressing. :(:( There are many palm gardens on the island with passive owners where this will go untreated, so it's sure to spread. :(:( I'd rather not get into chemical warfare, but if it's as serious as it looks, there doesn't seem to be an alternative.

Kim Cyr

Between the beach and the bays, Point Loma, San Diego, California USA
and on a 300 year-old lava flow, Pahoa, Hawaii, 1/4 mile from the 2018 flow
All characters  in this work are fictitious. Any resemblance to real persons, living or dead, is purely coincidental.

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George, I am sorry to see this. What a nightmare. I am curious why Bt would be found to be effective? In my opinion it would be a false sense of security. I have used it with great success on leaf eating caterpillars so I know it works but I couldn't imagine it would be as effective where the entry point is down on a leaf base and the area is so small they enter. Plus UV exposure and microbial activity limit effectiveness to about 7 days at best.

Also, you might want to ask if Thiametoxam would be a better choice over Imidacloprid. I know a professional talking about its effectiveness in the RPW thread stated it last 6 months over the typically 2 found in Imidacloprid.

  • Upvote 1

Len

Vista, CA (Zone 10a)

Shadowridge Area

"Show me your garden and I shall tell you what you are."

-- Alfred Austin

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ugh, that sucks. Sorry to hear of your pest problems Dr. George!

Matt Bradford

"Manambe Lavaka"

Spring Valley, CA (8.5 miles inland from San Diego Bay)

10B on the hill (635 ft. elevation)

9B in the canyon (520 ft. elevation)

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George, I am sorry to see this. What a nightmare. I am curious why Bt would be found to be effective? In my opinion it would be a false sense of security. I have used it with great success on leaf eating caterpillars so I know it works but I couldn't imagine it would be as effective where the entry point is down on a leaf base and the area is so small they enter. Plus UV exposure and microbial activity limit effectiveness to about 7 days at best.

Also, you might want to ask if Thiametoxam would be a better choice over Imidacloprid. I know a professional talking about its effectiveness in the RPW thread stated it last 6 months over the typically 2 found in Imidacloprid.

Thanks, Len - Agreed, the Bt likely is giving a false sense of security, which is why we are stepping things up - the hope was that with a surfactant it would penetrate into folds, cracks and crevices to kill new caterpillars before they burrowed down into tissue - but you are absolutely right, once they burrow in, its hard to get any topical to them.

The imidaocloprid systemic drench and granule formulations are supposed to give 12 months systemic protection for ornamentals in ground and in nursery (if you believe the labels). My guess is that its somewhat less than that. Even under the ornamental labeling, there is a max amount that we can apply within a 12 month period, so that may also limit what we will be able to do with it.

Am not familiar with the Thiametoxam, so checked out the NPIRS, HPIRS and Hawaii State pesticide databases. Being a farm, we have to be very careful about what and how we use pesticides, even on the ornamentals. Apparently, from what I have been able to find so far, Thiametoxam is only approved in HI in products combined with fungicides for seed treatment, killing termites in structures and as an ant bait gel. Will do some more checking though.

Thanks for the thoughts and suggestions - gmp

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The nematodes Steinernema carpocapsae would be very efficient killing these things in a solution together with Chitosan,poured at the growing points of the palms till all green leaf bases are filled with/drenched by ir,and also applied at the root initiation zone as this is considered a susceptible area of the palms for borers too. These should be very effective as they are very efficient at killing borers that affect palms like the Rhynchophorus ferrugineus and the Paysandisia archon with 98% death of all forms of the borers with each application,compared to just 50-70% of imidacloprid(varies depending on application method) and other chemical treatments.

Its worth looking around to find a formulation of these nematodes with chitosan but f you can't find a product and cant find info on how to make a formulation of these,I could help with quantities if you can get the raw materials :) And the best thing about them is that they are totally human and pet safe and even if you were to eat them and the Chitosan there would still not be any health concern!

Great suggestion. Bad news is that biologicals have to be approved and permitted for importation into the State of Hawaii. The good news is that Steinernema carpocapsae is one of the few biologicals that actually is approved and can be imported into the State with appropriate permits. Supposed to use 1 billion nematodes in a minimum of 200 gallons of water per acre. They are special ordered from the mainland through a Hawaiian distributor, sold in containers of 250 million nematodes in suspension, 6 months refrigerated life expectancy, has to be applied every 4 weeks, cost of $275 (US) for 5 containers (1.25 billion nematodes) and permit.

We used them to save a mature Teddy in 2011, and am not beyond going back to them, but as you know, they are more practical for treating individual infested palms than as a protecting/prevention strategy. If we find a hot spot that is a primary source of the buggers, the nematodes also may be a useful tool there.

Thanks - gmp

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Ugh, Dr. G, that's worse than the Gophers of Doom. That's more like the dreaded Red Palm Weevil.

The best hope will be a natural enemy biological control. Find out who's doing the research and help with funding, and, maybe volunteer to test what they find. That worked with the infamous Eugenia Psyllid.

Somewhere, there's a natural enemy out there.

Let's keep our forum fun and friendly.

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The nematodes Steinernema carpocapsae would be very efficient killing these things in a solution together with Chitosan,poured at the growing points of the palms till all green leaf bases are filled with/drenched by ir,and also applied at the root initiation zone as this is considered a susceptible area of the palms for borers too. These should be very effective as they are very efficient at killing borers that affect palms like the Rhynchophorus ferrugineus and the Paysandisia archon with 98% death of all forms of the borers with each application,compared to just 50-70% of imidacloprid(varies depending on application method) and other chemical treatments.

Its worth looking around to find a formulation of these nematodes with chitosan but f you can't find a product and cant find info on how to make a formulation of these,I could help with quantities if you can get the raw materials :) And the best thing about them is that they are totally human and pet safe and even if you were to eat them and the Chitosan there would still not be any health concern!

I don't see an advantage of using nematodes, when you have large palms. I use only chemicals and I have not ever lost one palm immediately to a borer. BTW I don't use imidacloprid anymore, i find it as the most unreliable among the neonicotinoids. RPW is well known to be attracted by male inflorescences of Phoenix spss and nevertheless I let all my Phoenix specimens bloom and get nevertheless no infestation.

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