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Post by pattyp on Mar 21, 2009 12:33:33 GMT -5
I just wanted to keep those interested abreast of some of the current scientific research regarding organic pest control. In a paper published last year in Frontiers in Ecology and Evolution, scientists Deborah K. Letourneau (from the Department of Environmental Studies, University of California, Santa Cruz, CA) and Sara G Bothwell published an article entitled "Comparison of organic and conventional farms: challenging ecologists to make biodiversity functional".
In a review of the literature, Letourneau and Bothwell found that species richness (or biodiversity) was higher among plants, predatory arthropods, non-predatory arthropods, and soil microorganisms on organic versus conventional farms. There was a statistically significant difference in the parasitoids that preyed upon herbivores, but also among the herbivores themselves.
This biodiversity helped with pest control on tomato crops: "Neither damage to tomato foliage by thrips, flea beetles, leafminers, or chewing insects, nor fruit damage by sucking insects and chewing insects, was significantly different on organic versus conventional tomato crops." Therefore organic farming methods, such as crop rotation, companion planting, and increased biodiversity were as effective in controlling for fruit and plant pest damage as pesticides were.
However, I should note that the authors end the paper on a cautionary note, calling for more research to confirm these trends.
Patty
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Post by ottawagardener on Mar 22, 2009 16:04:21 GMT -5
I just wrote about something similar but it had to do with intentionally letting weeds grow between rows (and within them) in a no till method to increase biodiversity as a means of having 'healtier' plants. It's in the soil building section entitled The Weedy Garden by Hida Manns or something like that.
There were a number of responses, I believe, that anecdotally supported this. I also remember talking to a nusery owner about his onion crop asking if he had any problem with leek moth or some other pest - don't remember which - and he replied, "No, but I have a big wild meadow right beside the field."
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Post by Alan on Mar 23, 2009 19:15:25 GMT -5
I've visited tons of bio-diverse, eco-logical, and organic farms in Indiana and Kentucky over the past several years and between my work here on this little farm experimenting and what I have seen, bio-diversity is the key to a well regulated and balanced farm eco-system.
Right now Kim and I are looking into bat houses for furthered insect control and crop pollination along with some further honey bee hives.
Honey bees are relatively widespread in their use on bio-diverse farms for pollination, but bats from what I have read and experience are a rarity, however their usefullness cannot be overstated on a small farm, pollination and insect control on wings!
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Post by ottawagardener on Mar 24, 2009 14:32:55 GMT -5
To do list:
Buy bat house
Wouldn't mind encouraging some barn swallows too - moisquito swallowers I like to call them.
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Post by grungy on Mar 24, 2009 16:31:24 GMT -5
Alan - curious - which plants do bats pollinate?
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Post by Owen on Mar 24, 2009 16:48:30 GMT -5
Although I've luckily never had to garden in a biologically denuded area, my observations on our farm are that biodiversity more than anything else (except maybe healthy soil) is the key to keeping pests in balance. Our garden is surrounded by meadows, brush and woods with all kinds of weeds, wildflowers and insects, and I've never really had a single species of insect proliferate to extent that they cause much damage. The other species keep them in balance. Of course in a good organic system it's not about eliminating pests or pest damage, but keeping them at an acceptable level.
The only exception to this trend that I can think of for me is the Colorado potato beetle, but who knows maybe they would be even worse without all this biodiversity!
One of the reasons we bought our place was the massive amount of life that we found in the old, formerly abandoned fields. Bats, toads, frogs, salamanders, spiders, crickets, butterflies of all kinds, bees, the occasional turtle, you name it. We're expanding the farm while retaining as much of their habitat as possible, and so far they seem to have stayed.
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Post by flowerpower on Mar 25, 2009 5:55:12 GMT -5
Bats are in decline here in NY and Vermont. They are getting some kind of disease and dying in big numbers. And rabid bats are not uncommon either. There are a good amt still in this area. But there are tons of natural caves too.
I live right up against a wetland area. So there are alot of frogs, toads, snakes, salamanders and birds around. I do let alot of areas stay wild. I suppose I could mow some of of these areas. But then I would get less blackberries and raspberries. I wouldn't see the Trillium, wild roses and asters bloom. Doesn't seem worth it to me. lol
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Post by ottawagardener on Mar 25, 2009 12:46:42 GMT -5
Owen: I am not sure if I have the true Colorado Potato beetle or the false one (I thought it was true and then something I read made me unsure) but they attack this annoying planting of chinese lanterns in preference to my crop solanums. I have often wondered if this was because they were up so early in the spring. They'll also eat the nicotina that's nearby but not the tomatoes, potatoes, eggplants, peppers, or annual physalias, sunberries or tomatillos. That's not to say that this year won't be their breakout year of course  |
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Post by pattyp on Mar 27, 2009 9:57:53 GMT -5
As a late addition to my original post (and perhaps one that takes us out of the realm of our own gardens and into the great garden that surrounds us), the professional journal Science published an article last week entitled "Humans Need Biodiversity". In it, the author describes the many ways in which we are dependent upon the diverse array of species around us, from archaebacteria to mangrove forests, poppies to sea squirts, red algae to dogfish sharks, and many more. He also notes that it is difficult to truly estimate the effects of biodiversity on humans since less than 10% of species have been described and we know even less about how those species participate in the ecosystem.
The argument for encouraging biodiversity around us is clear - if we cannot appreciate nurturing other species for their own sakes, we should do it for the health and welfare of our own.
Patty
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