[gib]

I’m wondering if there’s something wrong with my swan plant (a new one flowering for the first time this year.) I have observed several caterpillars grow to full size then become moribund. This morning I found a big one whose progress I’d been observing lying dead on the ground under the plant. It was about due to pupate. A week ago there were a lot of tiny caterpillars all over the plant, but now they all seem to have disappeared. Although I’ve killed a couple of wasps, they have been scarce this year, and I’m always on the lookout for any predators on the plant. I guess it’s possible that there are a lot more wasps that turn up when I’m not around, but last year I saw and killed many, in the end resorting to covering the plant with a fine mesh. Early in the season I located and destroyed a half-made paper-wasp nest, and killed its maker, and I think that has mitigated the wasp threat.

[Jacqui]

There are lots of predators if you sit down and make a list. I suggest covering the plant with net and seeing how it looks in two weeks – if there are second or third instar caterpillars there, you’ve eliminated the problem.

Also suggest you water and feed the plant well, in case it is too dry and the cardenolides (toxins) in the leaves are too strong for the caterpillars. Not sure where you are but if it’s dry, this is something to look out for.

[Author]

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