Pest and disease control 101: helpful hints for vegetable gardening
Keeping pests and diseases under control means a lot more than grabbing
for a chemical spray - especially if you're an organic gardener. I've
already raved on about why organic is better and
why you should ditch chemical gardening practices. It's better for
your soil, it's better for your little micro environment, and of course,
it's better for you.
So how do you achieve this organic bliss? The answer is easy - instead
of fighting nature, make nature work for you. It just requires a little
Pests and diseases can be combated in the organic garden by breaking
reproduction cycles, confusing pests - which keeps them away from your
garden, getting good insects to eat your bad insects, getting other animals
to eat your pests, and making your vegies and fruit unpalatable to pests.
We've titled this article 'Pest and disease control 101' as it introduces
the basics. A supplementary article, 'Pest and disease control 202' is
shortly on it's way and will go into details for specific symptoms and
Cutting a long story short crop rotation is about moving your vegetables
around your little patch each year. This way not only do you give your
soil a rest from having specific nutrients depleted each year, you also
help break the reproductive cycle of soil borne diseases and some pests
This is an important enough topic to warrant its own article, so you'll
find more specific and practical info on our crop
This is another one of those little organic miracles. By planting certain
vegetables, or herbs, together you can ward away pests, plus boost your
One of the best known examples is planting onions and garlic with carrots
(the allium's smell confuses pests, keeping them away from your carrots).
Any organic vegetable gardener should make companion planting an important
part of their planning. Again, for more detailed information see our companion
Don't reintroduce disease back into your garden
This sounds pretty obvious but it's amazing how many gardeners slip up.
Organic gardeners get fanatical about our compost - it's fantastic stuff,
full of basic elements and packed with micronutrients and micro-organisms.
But make sure your never put diseased plants in your compost bin or heap.
All you'll end up doing is bringing the disease back into your garden.
So toss diseased plants in the bin instead.
Get rid of bad insects with good insects. Confused? Don't be. There are
many insects you can encourage into your garden that pray on pests, or
use pests as the host for their young.
To get them into your garden try growing herbs with umbrella-style flowers
like coriander, fennel, parsley and Queen Anne's Lace. Their flowers attract
parasitic wasps (good wasps) that like laying their eggs into grubs, aphids
and other pests in the garden. The eggs hatch, and the larvae feast on
the host. Gruesome sounding stuff, but use it to your advantage.
These flowering herbs will also encourage ladybirds, which also enjoy
chewing on aphids. If you sow your beneficial herb mix but still don't
get any good insects, you might need to buy them in, try mail order, the
Internet or even some nurseries.
Other beneficial friends
You can also keep down the number of insects in your garden with other
animal friends. If you've got chickens or ducks you let them loose into
your garden and can just about guarantee you'll have no snails or slugs
left. Plus they'll dig up and eat other insect eggs on or just under the
soil. But keep on eye on your feathered friends, as they'll start into
your vegies too if you're not watching!
Or try turning to your natural environment and build a frog pond. Native
frogs and toads (not cane toads - for the Aussie audience) can make their
way into your vegie patch where they'll feast on your insect population
(indiscriminately though!) But you can't go past their croaking in summer
storms, or finding an amphibian acquaintance when you're out harvesting.
Pyrethrum - the big organic gun
When you want to indiscriminately (but organically) kill bugs you can't
go past pyrethrum sprays. A sweet smelling flower extract (bought from
nurseries) it should only be used on pests that you know (we've used it
on aphids when our ladybird population was low).
But be warned, pyrethrum residue lingers for a number of weeks, so it
can also kill beneficial or neutral insects that come by.
Deter pests with organic sprays
If you don't want to kill everything organically using pyrethrum, you
can always deter plant eating pests using handmade organic sprays.
These are aimed at any leaf eating insects - grubs, caterpillars, grasshoppers,
snails, slugs, etc, for almost all plants.
The idea is to create a foliar spray that will make the plant taste so
terrible, the pests will go away and annoy your neighbours, leaving your
vegetable patch alone. Not nice for your neighbours, but hopefully this'll
help you convert them to organic gardening!
Try mixing water with either (or a mix of) crushed garlic, chilli (hot
pepper) or onion. You might need to water it down a bit, otherwise it
might be so strong you mightn't want to eat your homegrown vegetables
Other gardeners swear by a mix of kelp (to help the vegies grow strong
and fast) and neem oil - which apparently tastes terrible. Neem oil is
an concentrated extract from the neem tree, native to India. We're currently
trialing this spray in our garden, so we'll let you know how well it goes
in the coming months. The only bad thing I can say about it at the moment
is that it is not cheap. I guess we'll soon find out if you get what you
Don't forget with any spray you'll need to reapply it after rain, or
if you water overhead with a sprinkler.
23 October, 2008
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