Monday, May 12, 2008

I'm Having Mitemares...



They're back. Punctually. I'd hoped this year would be different. I thought perhaps the cold, wet April which we had would have at least delayed them a bit. But no. Within days of turning the calendar, this is what I found.

Red spider mite.


Two days before there'd been no sign. My mallow, grown from a collected seed pod, was thriving, and I was looking forward to the first flowers. And then I go out to water, and what do I find - yellow, streaky wilting leaves.



Elsewhere, it can be the most idyllic month in the garden. But here in Milan, May onwards is a nightmare of microscopic red monsters sucking the lymph from my plants. I don't mind caterpillars, and I can cope with scale insects, but red spider mite has me waking on hot summer nights in a cold sweat. They are so insidious. You don't see the first few, but two days later there's a colony and your plants are dying, and if you wait any longer, that's it. They can reproduce from 36 hours old, for goodness sake, and will kill a plant in not much longer. This is what happens if you ignore it ...


What can you do about them? First of all, there are preventative measures. Simply misting the plants helps - pay particular attention to the back of the leaves, where the mites congregate. They thrive in hot, dry conditions - just what we have here on the balcony, and which are found in other enclosed spaces, like conservatories and greenhouses - so increasing the humidity helps. Before the infestations hit, I also spray with a mix of garlic, onion, cloves and cayenne pepper - but it doesn't kill off the mites if they do get a hold. Once that happens, the best thing to do is to pick off all the infected leaves, spray with water (or the mixture above) and wipe down the underside of all the remaining leaves. If you live somewhere where you can get them, there is a predatory mite - Phytoseiulus persimilis - which will clear any that you missed. If not, you may have to resort to spraying.

There are organic sprays on the market which you can use. I can't get them here so I can't comment on how effective they are, but I've spent the last month searching for Neem Oil - supposed not to harm bees and other insects - and according to
this article by the RHS, even the chemical companies produce organic sprays.

If you must use a chemical spray, choose one which specifies that it kills the eggs as well as the adults or you're wasting your time. If you combine it with misting and wiping, you should also be able to keep the amount you use to a minimum.


But even chemical sprays will only work if you catch them early. If not, give up. Pull the plant up and throw it away before the rest of the balcony, conservatory or greenhouse is affected too.

I seem to have caught my mallow early enough to save it. It looks a bit straggly where I've pulled off the leaves, but what remains seems green and healthy. And the infestation doesn't seem to have spread to anything else. But I know this is only the beginning. It's going to be a long hot, summer ...

There is of course another remedy, if you're really desperate. Just take the initial s off the word spraying, and possibly you have the only thing that could really work ...

6 comments:

Cheryl said...

Gosh I never realised how aggressive they were, what an absolute nightmare.

Helen said...

I hope you have caught your mallow in time - its really depressing to lose something that you have nutured from seed

Jane Marie said...

What a mitemare! You're right though, praying may be the only answer.

Yolanda Elizabet said...

Hope you are able to save your Mallow Sue and stop the infection from spreading. It certainly is a mitemare!

Andrea said...

Amen to that. That is EXACTLY what I do when I find an infested plant. In the garbage, right away! Or at least out of the greenhouse until I can get it sprayed but for the most part, I just send it back to the grower if I can and let them take care of it. Because if I sit on it, alot of times, it'll start infesting other things.

ladyluz said...

Argh...Sue, I do feel for your mallow. All the gardeners round here are complaining about black and green fly and the citrus mite. I've just spent three hours tackling the second honeysuckle and plumbago, which are covered.

Love your geraniums - they are certainly at their best here too, although have to be vigilant about the geranium moth that can destroy the pelargoniums in a matter of days.

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