Kitchen Garden Forum

I have 2 cucumber plants in the greenhouse. They seem to have suddenly got red spider mites, it has spread so rapidly. I had a look in my books but there didn't seem to be much hope. Any ideas anyone? Is there a brand name of spray, my books lists chemical names I don't know much about.
Am I better off getting rid of the plants before the mites spread to everything else in there?

Lucy found this link for you. Has some products on it so may be worth googling to see how effective they are and where you can get them. Good luck.

http://www.lovethegarden.com/pests-dise ... fAodmRKdTQ

VPM
x

lucysmum, do be aware that there are natural and very effective biological controls for red spider mite. I've included a link below to Ladybird Plant Care, which gives some useful information. There are others, just search 'red spider biological control'. Using natural controls lessens any risk of harm to our wider environment.

http://www.ladybirdplantcare.co.uk/red_ ... 4QodrRWsGQ

Two of the pesticide products listed in the link in the previous post - BugClear Ultra/Ultra Gun - contain acetamiprid, one of the 'neonicotinoid' pesticides which are linked to problems with bees. It pays to read the small print.

For a full breakdown of all garden pesticides containing neonicotinoids - they are widely sold - there's a comprehensive listing on the Pesticides Action Network website:

http://www.pan-uk.org/home-garden/list- ... icotinoids

I have problems with these. indoor cucumbers seem to do really well for a while, then the mites get to them, they turn yellow and stop producing. I tried a sulphur candle in the hope of getting rid of any overwintering nasties, but just ended up with corroded metal fittings, and the mites still come.

Are the biological controls mobile enough to wander off, or will they stay put in a well ventilated greenhouse ? They look pricey, but maybe worth a go.

Tony, it's a hard job to clear red spider once you've got it - they overwinter in every nook and cranny so it's a tough call to expect to be able to eradicate them. With biological controls you can kind of 'predict and introduce' if you know that the mites are bound to make a comeback. You need a keen eye. If plants are yellowing from red spider damage then damage has already been done, so it's best to monitor plants regularly and introduce the predators ahead of a big build-up.

The predators are intended for greenhouse use - they need the usually warmer conditions to do their job so are unlikely to go walkabout. They'll spread out over any affected plants . Amblyseius (see the link in my last post) is a useful predator as it's not so temperature sensitive and can feed on pollen if the mite supply dries up.

Pricey? I guess they are (it's worth shopping around) but by using them we're not passing on any costs to the wider environment, which we do in the manufacturing (resources, energy, pollution), marketing and ultimately the use of synthetic pesticides (more pollution and unintended consequences). Looked at as part of a bigger picture, biologicals are actually rather good value...

Thanks for that. At the moment I'm taking the pragmatic approach of planting both greenhouse and outdoor cucumbers, so that the greenhouse ones give an early crop, and the outdoor ones take over when the mites strike. But I'll consider trying biological controls next year.

Thank you everyone, it good to know its not just my greenhouse. This is the first year I've had problems with them . It's looking like I might loose my cucumbers though, they,re not looking well at all.
The biological mites look a good idea, but I not sure about in a greenhouse with them being so sensitive to temperature. I might think about it next year before it gets too bad.

John Walker wrote:Two of the pesticide products listed in the link in the previous post - BugClear Ultra/Ultra Gun - contain acetamiprid, one of the 'neonicotinoid' pesticides which are linked to problems with bees. It pays to read the small print.

And they are not approved for use on cucumbers anyway.

And thanks for the link, John. Whether neonicotinoids are responsible or not it is clear that bee numbers are severely down and avoidance of neonicotinoids is at least a sensible move.