Victoria Plum caterpillars

Just noticed the below on some of my plums.
Last year the tree did not fruit, the year before it fruited well and I did have an issue with what I expect was Plum Fruit Moth which I found upon opening the ripe fruits.

This year I am trying for the first time one of those plum fruit motn pheremone traps - it has been up for a few weeks and looking inside does not appear to have attracted much of anything, a few flying things of unknown sort.

Can anyone identify the caterpilars shown? I am wondering at this stage is the best option to jet spray each bunch of fruits this evening? Sorry not the best photo. They seem flattened against the skin of the fruit rather that a tube-like caterpillar.


Thanks.
GG

 

Hi GG,
http://www.gardenfocused.co.uk/fruitarticles/plums/pest-disease.php
The above link might be useful...they could be sawflies.
I think the pheromone traps come with a couple of capsules? You're supposed to refresh the capsule after a few weeks. If the weather there has been as silly as it has here, it'll be a tricky year to gauge when to put them up, and to replace the old one.
The jet wash might help, especially if you can borrow some chickens to clean up the fallen caterpillars

 

Hi Noisette
Yes it could be the sawfly.
Agreed the weather has been so dodgy it is difficult to calculate (if you can at all) when the moths might be doing their worst, I put it out to get a head start. I have a second pheremone capsule and will wait till the weather turns summery before changing it - think the two capsules are supposed to protect for one season.
I have jetted them and thinned a little. Fingers crossed as I have jam in mind for them.

Thanks
GG