Serious pest

[KARL]

This is probably the third or fourth year that I am aware of an increasing problem in my greenhouse. It manifests itself in the spring to early summer when the emerging leaves are attacked. Both things that grow there are suffering and it started on the peach tree (which is nearer to the doorway) and then spread to the nearest branch of the grapevine. The peach leaves grow to full size but, as they approach it, show increasing signs of insect attack (tiny spots and distortion of colour and shape) and ulimately dry up and die. The grape leaves form in a kind of miniature size and then die. At the end of it all there is a clearly visible, extremely fine web covering the entire branches. I have looked for the insects and occasionally have caught sight of what are tiny bugs, darkish in colour, but whether they are the culprit I cannot say for certain. Up to now the braches usually grow a second lot of leaves which appear far less affected or not at all - they then drop off in the autumn.

In anticipation of a repeated attack I sprayed the peach and previously affected branch of the vine with Ultimate Bug Killer which served me well before against a scale insect attack. We then went away for three weeks and on return everything was dead (leaves) and the web is there. Before cutting the vine branch off and felling the peach tree, I really would like to know what this pest is and whether I can hope to eradicate it and save the vegetation without any drastic cutting/pruning. Any advice would be most welcome.

[Hawkwalk]

I think there are two things happening here. I would suspect that you have peach leaf curl which is a fungus that attacks peach trees and then I think you also have red spider mite that is attacking the grape vine and possibly crossing over to the peach tree. If you look up both of those on the RHS website you will find some usefull info on them.

[KARL]

Peach leaf curl it is not because I know what that looks like. Thank you for your suggestion.

[murraymints]

i had something very like it and it was a red spider mite.... a very fine web with no obvious sign of pest... a nightmate and took a lot of time to deal with...lots of diluted fairy liquid in a spray....

[KARL]

Thank you murraymints for an interesting description of your way of tackling it. Having read the RHS description I am now pretty certain it is red spider mite (as, frankly, I had already suspected). It definitely started on the peach tree and went over to the nearest vine branch - the vine is enormous and the rest of it is perfectly healthy, hence my inclination to cut off the affected branch. By all accounts this pest is very difficult to control so reducing it to the peach tree might improve the odds. But ultimately I might sacrifice the tree - except I read that the bugs overwinter in soil and/or crevices in structures......what about cracks in bark, etc. too? So the battle may not be that easily won.

[murraymints]

Karl..after lots of fairy liquid...it did not over winter.....good luck !!

[mightymouse]

Red spider mite is a nightmare in the greenhouse, and can kill plants. The little blighters, which can only be seen with a magnifying glass are resistant to anything you can buy in garden centres. Prevention is advised........spray all plants at least once a day on the undersides of the leaves, they hate humidity.......only do this in overcast conditions.

Hope you have some luck, as they can kill plants. I grow many ornamentals and this spring is almost a nightmare.

[katerich48]

I read somewhere that giving them a good blast with the garden hose should do the trick.. I think I've got them at the moment - so I am blasting the affected plants when I water..