Sunday, August 06, 2006

On Pests and Diseases

I would love to be able to say that I’m a 100% organic gardener, but I can’t. I did try last year, but 2/3 of the way through the summer when I’d lost everything to red spider mite I gave up and drenched the whole balcony in insecticide. In order not to have to do that again, this year I’ve tried a sort of combination approach. I’m using organic remedies wherever possible for prevention, but at the first sign of real trouble use a limited amount of insecticide or fungicide and then go back to the organic remedies. It’s worked well so far – I’ve used relatively little in the way of chemicals, but have lost almost nothing. I would love to cut down still more though, so if you have any organic remedies which really work, let me know. One advantage of balcony gardening is that you can forget about pests like slugs and snails, but anything that can fly or is carried in the air still manages to arrive. Some of the problems I’ve had this summer are :

Rust : at the moment I’ve got a nasty attack on my begonias. I’ve picked off the leaves with the worst problems and I’m now spraying with milk. Apparently it’s an excellent fungicide and deals with various diseases, including rust. But it seems to be mainly recommended for powdery mildew, so I’m trying it on my calendulas too as they often get badly affected.

Caterpillars : these are a regular problem in the late summer. The type we mostly have come from a small brown moth and are green and “loopy”. I pick them off by hand and take them down into our courtyard and let them go on the rather weedy lawn. The idea is to avoid killing them, but I suspect I’m really just feeding the birds. When my son was little, we did have a "caterpillarium" one year. I planted some small spider plants in one those big containers which are used to store kids toys, covered it with foil wrap (with breathing holes) and transferred all the caterpillars we found to their new home. We then watched them as they ate, grew, pupated and turned into moths. It was fun, and as I always have thousands of baby spider plants growing on my "adults" (photo above), meant I lost nothing that couldn't be easily replaced.

Red Spider Mite : these are the bane of my existence and from April onwards take up most of my gardening time and energy. Last year I tried a garlic based spray, but it didn’t work, possibly because I waited too long before I started using it. It also meant that the whole balcony stank of garlic. This year I started looking for the beasts very early, and either picked off the leaves or, when I found just one or two, simply sprayed the undersides of the leaf with water and wiped the mites off. I then went on spraying all the plants that I thought might be at risk either with the garlic solution or just with water. With plants in smaller pots I simply upended them and stuck them under the kitchen tap. Except in a couple of cases it’s worked, and I’ve only had to use the chemical spray a couple of times for plants which I’d missed and where the mites had really taken hold. The chemical spray has been necessary though. My son was trying to grow runner beans, which we haven’t sprayed chemically at all, but despite all the water spraying and lots of tender loving care, they’ve ended up in a very sorry state.

Aphids : these have only been a minor problem this year. At one point I found a lot on my Mandevilla (photo right), but luckily the same day I found a ladybird wandering around the balcony - unusual, as they're not very common here. I transferred her to the Mandevilla and that solved the problem. But other years I’ve sprayed them with an oily mixture – it's supposed to clog the pores they breathe through.


Kel said...

have you tried predatory mites? they eat both spider mites and aphids - tiny, about 1/2 mm in length beige to reddish tan, predators to pest mites

lady beetles also eat spider mites

Sue said...

Yes, I have thought about the mites, but wouldn't have the faintest idea where to get them. My local garden centres aren't very into organic gardening ....

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