I don’t have any answers for you in my post this week, so there’s my initial confession or veg growing caveat. But I do have questions and ideas, and perhaps one or two of my readers may have some insider knowledge to share.
Something that I did in the garden has not gone as expected. I netted my brassicas, as usual, against pigeons and cabbage butterflies/caterpillars, and, as usual, it wasn’t completely fool-proof. There are always some butterflies that manage to get in and lay a few eggs and so of course there were lots of holes appearing in leaves courtesy of the newly hatched caterpillars.
After a particularly windy day, I took all the netting down, with the intention of putting it back over the brassicas properly once the wind had died down. In classic procrastination style, I never got around to it, and for a couple of weeks I berated myself every morning because the plants would be devoured by pigeons and caterpillars in no time at all and I really should re-cover them later that day.
When I finally got round to the task of re-covering them, I was surprised to find not a single caterpillar on the plants, and no sign of pigeon damage. Just a bit of slug damage, that’s all.
Confused, I wondered if I’d been getting it wrong all these years and questioned whether or not it might be better to uncover the brassicas once they are mature enough to withstand pigeon damage. Perhaps other garden birds were freely eating the caterpillars and keeping numbers down?
Google tells me that cabbage white caterpillars are unappealing to birds because of the heavy mustard content. Indeed, I’ve tried feeding them to my hens before and had no takers, so perhaps there is some truth in this. Equally, the hens aren’t very fond of any mustard leaves that I give them and never seem to eat the kale that I offer them.
I kept searching for an answer, and can only come up with two possible suggestions. The first is that some insect-munching birds do/will eat these caterpillars – like sparrows and goldfinches, and apparently skylarks. This idea is interesting to me purely for the fact that, for the first summer ever, we have had skylarks flying above the neighbouring fields. Perhaps they are feeding in my veg garden? The other idea is that, since it hasn’t been a very warm summer, there just haven’t been very many butterflies. If this is the case, I guess it could be true that there weren’t many caterpillars in the first place, but maybe more eggs will be laid over the next couple of weeks. I’d better keep an eye out.
There is a third option, but one that I have ruled out because I haven’t seen any evidence of it, and that is that the caterpillars are devoured by parasitic wasp larvae. I’d have thought that I’d see some caterpillars that are as yet untouched if that were the case, but even after very close inspection, I haven’t found a single one. Not even an egg. Interestingly there is no sign of caterpillars on the nasturtiums either, which is unusual.
I did wonder if perhaps there just aren’t any butterflies around, but I have seen several even just in the last couple of days. Are they just not laying eggs? Does anyone know what’s going on?