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Thursday, October 8, 2009

Organic Pest and Weed Control

written by Gavin from The Greening of Gavin

As I attempt to grow my vegetables in line with organic farming principles, without artificial fertilisers and petrochemical pesticides or herbicides, sometimes after a really hot day my broccoli and other brassica get attached by cabbage moth caterpillars. You see, the heat makes the usually strong plants wilt and I don't know if they have an immune system like up, but I do know that this is when the beasties are more likely to attack.

I started picking off the caterpillars at night with a torch by hand and throw them over the fence for the magpies (they love them). That works for a few days and then it is out with the torch again for another caterpillar throwing contest.

There had to be a better way, I thought. There must be some friendly way of deterring the little buggers (no pun intended). I performed a little research and there were only a few products on the market that are organically certified. I went to our local Hardware store to check out the pesticide section. I was gob smacked with the so many types of poisonous products on the markets just to grow vegetables. I can just imagine all of the harmful chemicals that you would ingest if you used these sprays and powders. 

I found only two organically certified pest control products out of about 60 that were available. Some people must not understand the issues with using these type of poisons, or they wouldn't buy them and the chemical companies would stop making them. Anyway, the two type available were Derris Dust and a product called Beat-A-Bug. Derris Dust is made from the Derris root which is native to Central and South America and contains a compound called Rotenone. It is long lasting and relatively safe for humans. It is a poison in large quantities, so follow the instructions on the label. I have found it very effective on brassica and silverbeet. It stops the caterpillars in their tracks. Just make sure that you don't use it if rain is expected as it is water soluble.

Even though Derris Dust is a good deterrent, it is not very good for sorting out aphids which is another pest I have to deal with. Aphids suck the life out of the new growth and they stunt the growth of just about all the plants they attack.  They are usually moved around by ants, so watch for them as well. This is where the Beat-A-Bug would come in handy, but it is quite expensive for a 1 litre bottle, so I make my own version. It is called the "All purpose onion, garlic and, chilli pest spray", and I found the recipe in a gardening book called "The Organic Garden" by Jeffrey Hodges. The spray is also a mild fungicide, antiseptic and antibiotic and has a very strong odour, just like someone opening their lunch box on a hot day that contained onion & garlic sandwiches! Here are the preparation directions;

"Combine 2 finely chopped onions and 6 cloves of freshly crushed garlic with 1 tablespoon of hot chilli powder (or 6 finely chopped red chillies), cover with 2 cm of water, stir well and allow to steep for 24 hours. Dissolve 1 cup of pure soap flakes in 5 litres of warm water, and then add the strained onion, garlic and chilli mixture and stir well. Use within 24 hours."

Now with most things there are some safety tips.

  • Always use gloves and wear a long sleeved shirt and trousers, as the chilli in the spray really stings on bare skin.
  • Make sure that if you do get some spray on your skin to wash it off immediately with soapy water.
  • Don't spray in windy, rainy, or very hot conditions. The best time to spray is early in the morning as the bugs are less active.
  • Don't harvest sprayed plants for about 2 days. Natural sprays will breakdown after about 12 hours unlike petroleum based sprays. And of course you don't want you fresh vege to stink of garlic and onions.
I make the pest spray up whenever I need it and spray the next day. I have also found that the plants go through a growth spurt a few days after spraying for pests, so the plants must absorb some of the nutrients in the spray! An beneficial side effect in the best possible way. I use the spray about once a month to keep things under control and hand pick caterpillars or aphid damaged vegetation in between sprays. If you really don't want to mix up this potent natural pest spray, try Beat-A-Bug instead. I think that the only extra ingredient it has is pyrethrum so it is a good alternative if you can afford it.

Now that you know about organic pest sprays and powders, the weed control is so much easier. Mulch is the answer to all organic gardeners problems. Mulch thickly in spring and summer and the weeds hardly get a chance to germinate. Any of the few that do get through, I pull by hand and throw in the compost bin. Any grasses that manage to pop through the weed matting under my paths are simply killed off by pouring boiling water on them. They die within a week as their cell walls bust and the plant wither and expires. I use left over cooking water or boil up a kettle of water. It works well and beats having to pull them out by hand. It is also very friendly on the garden and is so much better than using glyphosate (roundup and zero manufactured by Monsanto) which is harmful to all life and causes cancer in humans.

By using these easy tips, I hope you avoid the poisons and switch to organic pest sprays, and that you have a successful and healthy organically grown garden just like mine!


Chiot's Run said...

Several years ago I switched to "organic" sprays, but then the more I read the more I realized that even organic ones are not beneficial since they don't discriminate. They kill beneficial bugs along with the bad ones. I decided that to truly be an "organic" garden I would have to cease using all products and only use natural methods. Any method should only be used as a last resort, if absolutely necessary. I personally would rather lose a cabbage crop than put any kind of treatment on my plants.

This summer I was at my wits end with cabbage loopers and my plants were looking like swiss cheese. I had placed wren houses around the garden in the spring and had 2 nesting pair of wrens.

The amazing thing is that the wrens chicks hatched out in perfect harmony with the worst of the cabbage worm infestation and within a few days I couldn't spot a single cabbage worm in my gardens. The wrens captured every single last one of them and fed them to their little chickies. If I had used an organic pesticide the wrens probably wouldn't have had enough food for the chicks and they probably would not have come back to my gardens next year.

Often the things we see as "pests" in the garden are actually beneficial for other birds, bugs and animals and occationally even for the plants they're attacking. We don't know the damage we're doing by "treating" for them.

Anne said...

As well as a large vegetable patch I am trying to establish over 100 roses. Over the past few weeks the aphids have been out in their billions. I have been picking these off or spraying with soapy water. My main strategy is to let the lady bugs build up and they will take care of the roses. As of yesterday the lady bugs are definitely winning. There are only a few aphids left. The only casualty has been a few rose buds. Last year this happened and we had aphid free roses until June.

Deb said...

Someone "planted" perch, bass and goldfish in a mountain lake near here (Canadian Rockies) a few years back. They are prolific breeders, and ate all the insects in the lake, starving out the native trout and amphibians in the process. Bird populations plummeted.

So this week the Fish and Wildlife folks poisoned the lake with Rotenone. Kills everything, fish by the thousands on the shore, and any bird who eats them will die too. I wonder about any deer, moose, bears, elk, goats etc that drink that water. In *that* concentration it's toxic to everything.

That lake serves as drinking water for several small communities who now will have to have water trucked in, or drink bottled all winter.

Thanks, but seeing the Hazmat suits on those guys just reinforced my belief that poisons, even "natural" ones, do us no favours.

I feed the birds all winter and right into breeding season, even though my neighbours say it attracts mice. Once insect populations swell I quit feeding the birds and they get busy eating bugs. I have watched Finches beat the stuffing out of big Tomato hornworms, very entertaining, except for the hornworm.

I have used a garlic, soap and chili pepper spray to repel *racoons* in my garden, and it worked well. They left my stuff strictly alone.

For my neighbour's aphid problem I bought a sheet of yellow poster board, cut it into three inch squares, punched a hole in one corner, smeared a coat of vaseline on it and hung it on the infested plants. Aphids love the colour yellow and will leave a leaf (no pun intended) for a bright yellow card. And there they stay.

For what it's worth I had no aphid problem, though our plots in the community garden were adjacent and we grew many of the same plants. I used ground red volcanic ore as a supplement, just minerals basically. Had few insect problems but the critters loved my stuff!

Love your blog Gav, read every post. Deb in British Columbia

Helen said...

I don't know if someone already said this, but I was told a really good tip recently - make little bows out of white ribbon, about the same size and the moths, and spread them around the garden - hang them from string, stick them in the ground with wire, etc. Apparently this lets the moths know that this territory is full already, and they stay away!

Gavin said...

@ Chiot. I don't have the privilege of having wrens around here in Australia. Most of the native birds not only eat the bugs but will take the plants with them as well. I would love to go totally organic i.e no spray at all, but in my small garden, there wouldn't be much of a crop left for me.

@ Anne. I too use the soapy water methods for roses and it works well.

@ Deb. I did mention that Rotenone was a poison in large quantities. I would not recommend it as the first line of defence. This year, I simply picked the cabbage moth caterpillars off by hand and fed them to the chickens. It worked better than the spray! Also, thanks for the tip about aphids and the yellow card. Haven't heard that one before.

@ Helen. Yet another good tip. Will have to give that one a go next year when I grow brassicas again.


Chookie said...

Hi Gavin, I had so much to comment that I thought I'd better just put a post on my blog about these caterpillars. Hope you like it!

Damn The Broccoli said...

One thing to be careful of with Garlic based sprays is the level of sulphate they contain which is naturally present in the garlic. I have found this sort of home remedy in several sources that all warn that some types of plant don't like it, I think it is mainly squashes though, as I was researching powdery mildew on squashes at the time.

Anonymous said...

Dear Gavin,
I live in Perth, Western Australia and in the city. I feed the magpies with birdseed and in Spring I regularly give them a few small pieces of bread. Well, they reward me with pest control. I don't spray spiders and the large Wattle Birds come around at dusk and dawn and clean them up. I talk to the bird whenever I'm outside(just like Jackie French) and believe they become used to you. I don't have a dog or cat though.

msbetterhome said...

I'm growing container veggies in a very small inner city back yard, but fortunately we have lots of mature trees, & lots of birds. I'm trying to send friendly vibes to the praying mantids, ladybirds, spiders & wattlebirds, as we have quite a few of those.

I don't have many brassicas, so the 'picking the caterpillars off' method works for me, too. I did have some leafminer in my pumpkin leaves, but seem to have subdued it at last. The one thing I seem to get swamped by, though, is whitefly, and I'm not sure what to do about them, other than soapy water. I guess Beat-a-bug might be a last resort there.

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