Spider Mite help needed.

[vegmandan]

Yet again I have got red spider mite on my butternut squash plant leaves and they are shrivelling before my eyes.

As they are in a polytunnel with other plants, I can't really raise the temperature and humidity to help them as the other things wouldn't like it.

Is there any pesticide on the market which might work ?

Any thoughts would be appreciated. :)

[vegmandan]

[tim]

Parasites work. But if the mites are well established, it could be cheaper to buy your squashes?

[ceres]

If you don't mind spraying, Provado can be used on edibles.  It's widely available and not expensive.  I think Wilko's might have it.

[realfood]

For the first year ever, I have a red spider mite attack on my Winter squashes, and they are outside, open to the elements. I was a bit slow spotting what was wrong but I have now sprayed them with derris.

[Slug_killer]

Derris is good, if you can find it on sale anywhere as its now a banned substance (due to paperwork reasons, not chemical effect reasons)

Spider Mite like hot dry places. If you can raise the humidity, or lower the temp. they go elsewhere, however if the infestation is large, spraying is the only way.

[ceres]

Derris isn't banned until 10 October 2008.  Amateur growers have a year to use it up after that date.  My local 99p shop is selling it, so bargains to be had!

[Barnowl]

SB Plant Invigorator is an environmentally friendly spray. 

It's expensive but you use it very diluted and apply as a fine mist so it goes a long way. Ignore the instructions about spraying once a week, which are more about plant growth, just spray twice three days apart which will interrupt most insects breeding cycle. It's important to spray the underneath of the leaves not just their upper surface.

Spider Mite like a dry and still environment: I mist my GH plants most evenings and, again, it's important to spray the underneath of the leaves not just their upper surface.

[tonybloke]

you could try planting a sacrificial crop near the infestation (nicotiana, broad beans). the mite should move onto these plants!! ;)

[davyw1]

Red Spider Mite is not the easiest pest to get rid of, when its finished sucking the life out of your squash it will move onto some thing else if it has not already done so.
There is very few insecticides that will kill it, i know that Bug Clear, Doff and so on state it kills the mite but it does,nt as they are immune to them. You might try Duramytex available from pet shops at about £7.50 but read the instruction before you buy it. There is another product which show leek growers use but i think its only available on licence ( i will post the name tomorrow ).
What i would recommend is you don,t visit other people garden or let other gardeners in your tunnel as the mite will transfer to the warmth of the body, if you put your hand next to an infected plant you will see the mite come onto it.
I would remove my Polly tunnel skin and sterilize the whole area as the mite goes into the ground and any cracks that is available and over winters.
I am afraid you have have very few options.

[Barnowl]

Davyw1, aren't you being a bit of a doom merchant? :)

Surely unlike a greenhouse a poly tunnel doesn't have cracks for the mite to over winter in. Won't a good spring clean spray with Jeyes fluid, Armillatox, Citrox or similar should get rid of any mites trying to over winter?

In the present case I'd use a spray  once or twier then make sure the dryness doesn't reoccur by regular misting.

In each of my first two years with a GH I had spider mite infections and got rid of the first with an anti bug spray,  leaving the greenhouse door and windows open and misting every evening, The second I approached in the same way but without a spray. It worked but took longer and more damage was done in the meantime.

[manicscousers]

there is a biological control available, just google red spider mite, bit expensive but it works  :)

[davyw1]

BARNOWL, Perhaps i am but when i think of Polly tunnels i think of raise beds in them and the mite hides in whatever walls you are using for the bed as well as the soil. Also i tend to forget that our tunnels are self build and designed so we can roll the skin into the middle.

As you should change the soil in a Polly tunnel every couple of years because of a build up of minerals and salt or flush it through which takes a lot of water to do so you would be doing both jobs at once by using what you suggested Jeys Fluid etc and allowing the elements  to do the rest.
Most spider mite are now immune to most bug killers so my attitude is if i have to do it i do it once.
I did not mean to sound like a doom merchant but unfortunately as you have learned the mite is not easy to get rid of.

[tim]

Like I said on day one, Scousers?

I can only speak for greenhouse Cucumbers but, for them, vigilance is the key.

As soon as you see any sign of web at the leaf/stem junction, ACT!

1. Remove.
2. Regime - mist etc.
3, Predators.

[Tyke]

mmmm... I have a problem with my gooseberry. I bought it in February and put it in a large pot. It grew lots of leaves and doubled in size by May. It then produce 3 berries - which i cropped far too early!

However, it has started slowly looking very ill. The end leaves are slowly turning brown and dropping off, while there have been no more fruit or flowers. I have found no catapillars or slugs. I have scraped of soil to look for something in there and found nothing. A few leaves in the middle look like they have been nibbled.

The reason why i've put this post on this thread is that Tim's post might be a clue. About 10 of the leaves have a small amount of web-like stuff on them and the leaves were curled up. But i couldn't see any insect or catapillar in there. Do you think spider mites would attack gooseberr?

[realfood]

Provado was mentioned for red spider mite, but take care that you use the Provado that can be used for edible crops.
Provado ultimate bug killer cannot be used on edible crops.

[ceres]

Good point realfood.  Should have mentioned there are several Provados.  I don't use it, but an allotment neighbour swears by it for spider mite

[valmarg]

I really don't like using insecticides on anything we eat.

Red spider mite do not like damp conditions, so fine misting with water helps to control them.

valmarg

[star]

With you 100% Valmarg. Its the cheapest most effective way, they hate water!! But you must get all the undersides of the leaves.

[Barnowl]

BARNOWL, Perhaps i am but when i think of Polly tunnels i think of raise beds in them and the mite hides in whatever walls you are using for the bed as well as the soil. Also i tend to forget that our tunnels are self build and designed so we can roll the skin into the middle.

Good point. I hadn't thought of the raised beds etc - more difficult to sanitise.

[davyw1]

What we use for our show leeks should we get Red Spider Mite is Dynomec and Durrsban