Hippeastrum and lily borer: treatment tips for the tropics?

I think it’s a Hippeastrum not an Amaryllis, but it was gorgeous.

There I was yesterday morning quietly eating my breakfast while perusing the garden. First I saw that the possums had been wreaking havoc on my new tomato bushes…nothing new there. Need a new strategy.

All of a sudden I realised my pot of beautiful Hippeastrum plants looked like a plague of phytophthera had hit it…the leaves were like mush and wilted and in short the whole thing looked on the brink of death. Porridge forgotten I shot into the pool area to see what was going on. As I pulled one leaf after another from the plant, landing mush-like on the ground I had images of my Irish ancestors checking each potato tuber after the Blight had infected their food source. At least I was only obsessing about some flowers, not my food and sustenance. But I wasn’t happy!

You can see the borer track and how it’s turned the bulb reddish.

Then I noticed there were some black and white-striped caterpillar/grubs on some of the leaves (no photos of my own, too busy killing!). One thing led to another and I kept finding more of these critters. Don’t know why I pulled up some bulbs, but they too were going mushy – and there were worm holes down which the grubs had burrowed, cutting through the bulb in a wormy tunnel. Well I sliced and diced, stamped and stomped, battered and pulverised every one of those little *** I could get my trowel on. Stuck skewers down the tubes and squished with all my might. No grotty little grub messes with my flowers!

This is one of the little monsters that caused all the trouble…long since deceased.

In the end I sorted out which bulbs will probably not survive, though I replanted them in the contaminated pot, which I hope I’ve cleared of bugs. The healthy-looking bulbs I’ve planted in another pot, with my fingers crossed. Then I remembered that last week there’d been a maze of tiny fruit-fly sized flies around the adjacent Thai basil. Were the two things connected? Spotting some more of the flies I zapped them with common house fly spray.

A good deal of googling suggests that those wretched grubs are lily borers and they are remarkably efficient in decimating a plant. I’m still not sure if the flies are linked to the grubs but I’m thinking so. Some comments suggest these grubs are incredibly difficult to control but I’m hoping my homicidal tendencies have taken care of them. I’ve also learnt the bulbs themselves are toxic – kind of handy to know when there are children around.

I’ve had them in the pot for about 4 years (and yes, I should have divided them up), and they get a steady amount of water and during the Wet Season they’re deluged.  Ironically the rain had dried up in the past week and the temperatures dropped. Typical for this time of year, but did the changed conditions contribute to the infestation or was it just bad luck?

But what of my remaining bulbs? Any suggestions? Can I save them? There’s really no point in replacing them while these voracious monsters are still potentially in the garden.

Update 19th May: I sprayed the pots several times with a mix of water and tabasco sauce, as per some clue I found on the web. Whether it works in the long term remains to be seen but at least I’m now seeing some little shoots regrowing. Fingers crossed.