The Icebergs are of the variety Maugli and have done exceptionally well in the polytunnel. In fact, this time a few days ago they were really looking the real deal. But then holes started appearing. Just a few small ones at first. I sprinkled some organic slug pellets around the lettuces, but the holes carried on, gradually increasing in size and frequency until some of the lettuces started to look a little ragged.
It was becoming clear that slugs were not the problem. No slime and no remedy despite the pellets. There were also now tell-tale piles of black poo. I delved into the leaves of a lettuce and there I found a bright green, looping caterpillar. The caterpillar hunt went into overdrive and I started finding more and more, bigger and juicier specimens. Beautiful as they were, they most certainly were not welcome. I picked off as many as I could, squishing them disgustingly between my fingers, but it was clear there were more tucked deep down, inaccessible between the hearting lettuce leaves.Research confirmed that these lime green loopers would, if allowed, grow up to be small white cabbage white butterflies. Not having grown lettuces particularly successfully before, I stupidly hadn't even realised that they would be targeted by cabbage whites.
As picking them off was not going to be effective, I decided to prepare a soap spray. Not ideal on salad leaves as it might scorch them and they would need a good wash before eating, but the best option available. I took to the interweb to remind myself of the best solution to mix up and very quickly came upon an alternative organic solution - flour!
So at 6am this morning, before the blazing sun was having too much effect (yesterday the thermometer in the polytunnel was at scorchio!), I sprayed the lettuces to simulate rain or dew and then applied the flour sifter.The icebergs had snow on them!
Apparently, the caterpillars are supposed to eat the flour which causes them to bloat and die.
ed - if you're wondering how I've got scorching weather here when you've got clouds and drizzle, this post was written just before the lightning storm took out my broadband. Things have moved on a bit since then. As for the lettuces, the flour was quite effective, but not before the caterpillars had done enough damage to really spoil them. I even found one which had made a cocoon inside the lettuce.
I have some more seedlings on the go though. I'll net the next ones!
I've had this problem before I put net over the poly door but you have to be careful not to keep out smaller pollinators, I also use crunchy cockle shells to deter slugs. Loathe to let my ducks in as they have very big feet!
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