Yes it is. Ma Nature does not give her plants an unbalanced diet and those "weeds" then are not all that attractive to the insect pests although some are just to help maintain the species. That concept is one of thpse that organic gardeners/farmers should be familiar with and one that I have talked about here with much derision from unbelievers.

Well I've seen weeds and wildflowers take a hit from disease and bugs but it's usually only in an extreme environment. You have to think about the breeding involved. We breed plants for taste and preservation to market and unfortunately have to give up some survival mechanisms for that. I do believe we have done too much breeding for dollars and not thought of the longterm affects but hopefully we can put that behind us and move on. Change is a fearful thing and the forefront people need to explain quietly, reassure the masses and keep chanting and pretty soon they will put down the koolaid and follow you.

kimmsr: I agree with you on the unbalanced diet -- I am presently trying to decide whether to give my onions a shot of nitrogen. But I'm unclear about your "not all that attractive to insect pests" idea. My notion of plant/pest co-evolution is that individual plant species or families developed resistance to all insect species except a few that were able to adapt to a point where they could break down the plant's natural pesticides. At that point the insect had a competitive advantage because its favourite food was not used by most other insect species.

So we have insects specializing in selected food plants -- soldier beetles don't eat potato leaves and Colorado beetles don't eat goldenrod pollen and so on. So, in a word, all weeds and wildflowers are the favourite food of something, to which they are attractive. But they still don't get eaten down to their stalks and plant ribs. Would this fit your theory: poulations of those insects we call pests and those fungi that cause diseases to cultivated crops are many times more numerous than they were before there were any cultivated crops? I can see that this certainly must be the case for Colorado beetles, which once made a living off a sparse population of horse nettles and their near relatives but now have wide acres of potatoes worldwide to feast on.

shebear: your point is an excellent argument for seed saving. One would only select seeds from plants that successfully resisted pests or disease. And so resistance builds with each generation. I save from half a dozen species; I should do more. Potatoes are a dead loss, however, being clones. I wonder what the situation was a century ago when plant breeders did select for pest and disease resistance. I mean, was there less damage to cultivated crops than at present?
Regards, Peter.

Most people, many organic gardeners included, tend to add far too much plant food in the form of readily available nutrients which causes lush growth that is attractive to insect pests, and we tend to plant large blocks of the same plants which makes it very easy for plant pests to find them. A lot more intercropping, companion planting, and less "fertilizer" and more attention to the soil would help. Think more in terms of what the soil needs and less about what I need to add to promote rapid, lush, insect pests and disease attracting growth and you will see less of that.

kimmsr: Thanks; obviously what you say is true. Does it follow then that before there were cultivated crops insects found it hard to make a living -- both those insects that eat crops and the insects that eat those insects? And, as a consequence, there were far fewer insects in pre-agricultural times? Or is it that weeds and wildflowers were much more affected by insect pests and diseases than they are now? I can't easily see either being the case, and so I am left wondering why weeds and wildflowers are apparently immune to insect damage and disease. Regards, Peter.

Insect see the yellow in less than healthy leaves and are attracted to those plants as they fly over an area. Vibrant healthy plants therefore, tend to resist eating insect. My guess is weeds are not attractive to insects for much the same reason they are not attractive to us.

I intercrop and companion plant, I don't add any fertilizer, and my soil, as far as I can tell, is just fine, and darn it if those stupid slugs STILL don't eat up my marigolds every spring.

Furthermore, those same slugs also ate up my Asclepias tuberosa seedlings -- which are weeds/wildflowers. Which reminds me that I used to have Asclepias incarnata plants, which are native plants, but some tussock moths (also natives) ate them down to their stalks, and that was the end of them.

And trees certainly can show signs of damage from pests and diseases; even native trees, with native pests and diseases.

So I don't think it's accurate to say that plants growing under optimal conditions don't suffer insect damage or disease, any more than it's accurate to say that one must use pesticides or everything will get eaten up or wither.

I have noticed exactly the opposite. My wildflowers and tree leaves are full of insect holes and the bergamot always has powdery mildew.

Caterpillars always eat my milkweeds down to stalks. :-)

But the native plants, can withstand the insect damage... they are not ruined by them, they keep coming back year after year. (At least in my yard?)

Not having evidence of insect damage on a plant in my yard is a void in the ecosystem.

{{gwi:141213}}

So then we here in California don't have to worry about sudden oak death that is sweeping through our forests because there is a balanced nutrient diet in those soils? Whew, that's a relief.

Yes it is. Ma Nature does not give her plants an unbalanced diet

Of course she does. Weeds (native plants) sow seed randomly. Some land on ground ideal for them, others land on ground they can't even germinate in and others somewhere inbetween.

When I walk through forests that nobody spreads Miracle Grow or compost in I see plants in all stages of health/death.

Insect predation is certainly not uncommon, sunlight starvation is not uncommon and neither is nutrient deficiency. Certainly the forest, overall, is healthy and the plants not making it will just become food for those that are, but the idea that weeds are immune to pest problems is just... not accurate.

If not for weeds those of us in the north wouldn't see cucumber beetles migrating in. They certainly don't make the trek just for my veggie garden. Garden pests subsist not on human grown plants, but weeds (native plants) and find our garden plants appetizing as well.

joeypieweed what's the cute little guy in the photo?

People that are elemtary organic gardeners/farmers often think that any insect damage to any plant is unacceptable while those that are more mature know that there will always be some insect damage. Ma Nature provides balance, nutrients, insect populations (the beneficials would die off if there was nothing for them to prey upon many of which we consider pests), other insect predators and predators of all kinds. We establish a garden without considering that natural balance and expect that what we plant will grow up and not be bothered by any insect or plant disease. We plant mono cultures, many plants of the same species together, which helps the insect pests and diseases spread around. We spray often with highly toxic poisons and wonder where the butterflies and Lightening bugs have gone. We disrupt the balance of nature and wonder why plants die of strange, exotic diseases or strange, exotic insects, because many of us do not understand what that balance is or needs to be.

So what balances out the populations of cucumber beetles and japanese beetles? Last I checked very little eats either and many gardens are infested with them simply because there is a high population in the general area.

If we are to seek a balance, please let us know how we balance out the pest/predator relationship with pests that have no predators other than humans.

Cucumber beetles are native, which suggests to me that first, they found something to eat long before I arrived with my lemon cucumbers and costata romanesca zucchini, and second, there was something out there to eat them -- for example, soldier beetles, tachinid flies, braconid wasps, certain nematodes, and bats. (Thank you, ATTRA. http://attra.ncat.org/attra-pub/cucumberbeetle.html)

Japanese beetles are not native, it is true. Nonetheless, as my ecology professor liked to point out, "The world is green." Something must be limiting the Japanese beetle population.

Malcolm Beck wrote an article in the book Lessons in Nature about an observance he had that large farm plantings of crops (Now not quite a monoculture, just a plot of many on a traditional farm) had less overall damage due to safety in numbers vs. the small home garden where you literally have just a few cucumber or squash plants that once found, are the sole feast around.

trancegemini, the cutie is a monarch butterfly caterpillar eating asclepias incanarta (a native milkweed) in my rain garden.

Predatory organisms can be used to control populations of cucumber beetles. Natural predators of this pest include soldier beetles, tachinid flies (Celatoria diabroticae), braconid wasps, certain nematodes (38), and bats. (29) In California, where the tachinid fly is the most important natural enemy, it is rarely sufficient to reduce populations of western spotted cucumber beetles to below economically damaging levels.

Get it? Natural predators are rarely sufficient. So please tell me again how to achieve a natural balance?

I don't know where you live, but I have seen plenty of insect damage to native plants. AND I have seen plenty of insect damage in organic gardens also. You might have to get out of an area that is heavily populated to see it but there is plenty there.
JMO,
Tom

joepieweed that is a great photo. I just did a search on google to see what the monarch looks like and I'm pretty sure I get them here, but I've never seen the caterpillars. I think my garden is in need of some good host plants, he's adorable :)

I'm not used to doing close readings at 6:30 am, but it seems to me that what this says is that TACHINID FLIES are not sufficient in CALIFORNIA to reduce WESTERN SPOTTED CUCUMBER BEETLES. It doesn't say anything about other predators, or, for that matter, gardens -- unless you're selling your garden produce?

I stand by my premise, certainly as it relates to weeds. I have seldom seen any serious insect or disease damage on weeds, and I still seek a convincing reason. Certainly a part of the reason is that they grow where they choose, not where we choose. I do admit to observing more damage to wildflowers and wonder why wildflowers and weeds differ i8n this resprct -- if they do. But as to wildflowers, damage to wildflowers grown in a garden doesn't count -- they are cultivated wildflowers subject to the same pressures as vegetables and floral cultivars.

On the positive side, can anyone report success in breeding insect or disease resistance into garden plant by seed saving?

Regards, Peter.

Peter, Define weed. A weed is a plant out of place. Its a plant, any plant, growing where its not intended. Kentucky blue grass is a weed in a corn field and corn is a weed in a Kentucky blue grass lawn.

Its about "plants" and lets not tag some plants with the term "weed" or the term "wildflower"...

joepyeweed: I plead not guilty to you soft impeachment. You're a gardener, I'm a gardener, and we both know which species are weeds. So although your observation, which I've heard before -- believe me -- sounds wise, it's really unhelpful. Those things you and I call weeds (or do you never do any weeding?) are -- it appears to me -- highly resistant to insect pests and disease; and I'm still looking for more ideas as to why this might be. Regards, Peter.

Peter, the largest plant in the back yard here is a maple tree. For the last three and a half years this maple tree has (by weight, volume, mass, surface area -- whatever measure you wish to apply) displayed the largest amount of disease infestation and damage of any plant, or any group of plants, in the entire back yard here.

Over the course of the growing season during those years, nearly every leaf I've examined on this maple tree clearly and obviously shows the signs of what I think is a black spot fungus.

Now, I'm not a plant disease expert, but I grew up around both cultivated and wild maple trees. They grew in the front and back yards of the house where I was raised, they grew in the wild all over the property of our family cottage where I spent many winter and summer weekends from the age of five until 35. I've climbed maple trees, cut down maple trees with axes and chainsaws, split maplewood and burned maple logs and leaves and branches from an early age. As a carpenter and woodworker, I've worked with maplewood. Including green and kiln-dried and spalted maple.

So, p'haps you'll take it somewhat seriously when I tell you: this maple tree shows more pronounced and more obvious signs of illness than any garden plant I've grown in the last three and a half years. Including tomatoes, onions, peppers, lettuce, garlic, basil, parsley, and many other plants which aren't native to this city, province, country, continent, or this hemisphere. Much less this local ecological region.

And if you're tempted to say "but trees aren't weeds!" all I can do is mention the day I spent a week ago, digging young maple trees out of the back yard flowerbeds. Those trees sprouted from maple keys dropped by the same diseased tree. They grew like weeds. And I have little doubt they would have acquired the same disease their parent tree displays.

You keep describing your personal experiences in your local property. These are mine. My personal experiences are different from yours. And therefore, your personal experience is not universal.

IMO, you're entirely welcome to write here about your personal experiences. I do it all the time -- see above.

But... as soon as you claim your personal experience is 100% true for all situations, and the experience of others is 100% invalid and therefore to be dismissed -- I demand evidence, sir. Proof. From you.

You began this thread with a question, Peter. You have continued this thread with an assertion -- that weeds are highly resistant to insect pests and disease.

Your assertion is not correct. Not in my experience. It may be true of some weeds, at some times, in some places. Yet in my time in the wild -- which includes not just the weekend visits of three decades into unspoiled country, but two solid years working in the virgin uncut forests of northwestern Ontario, north of Lake Superior; forests which had never been cut prior to the time I spent up there -- I saw regular and recurrant evidence of plant diseases and insect damage to native plants.

So, please: feel free to provide the evidence, so all of us can learn. Evidence which proves your personal experience and your ideas are more correct than my personal experience and ideas.

I look forward to learning from you.

All the best,
-Patrick

p.s. Note flag, below. The leaf at centre is not from a tomato, onion, pepper, garlic, basil, or parsley plant. All of which currently grow in my back yard gardens with less disease than the maple also growing in my back yard.
{{gwi:141214}}

madmagic: interesting response. I too have observed maples in bad shape; they were Norway maples and/or singletons in cities. Is your maple either or both of these? It seems to me that trees not only need their leaves back but any boughs that fall (and, eventually, the trunk) to feed the soil and keep them fed and disease resistant. And what we do in urban settings is to remove all that stuff. The native maples I observe in undisturbed tracts of woodland do have lots of insect galls but are in perfect health. I have to accept that American chestnut, American elm, and the ashes haven't done at all well, but that's our fault by unwittingly introducing foreign invaders. It is with the species we call weeds, however, where I note the greatest resistance, not only in gardens but in hedgerows, farms, along railways, and in old fields. I admit my observations are idiosyncratic but I don't regard them as inconsequential.

How's this for a hypothesis: a chap called Bruce Taino (a microbiologist if I remember aright) has done lots of tissue analysis of nutrient levels in wild plants. He avers that most have a pH level of 6.4 and that no insect or disease will bother them when that is the case. Are you able to measure the pH of the sap from your maple's leaves? It's a bit tricky to extract enough sap.

By the way, I'm old enough to remember pre-Lester Pearson days when the country's flag was the Union flag. Regards Peter.

I grow native plants. I cultivate plants that many would consider weeds...so when you say "we both know which species are weeds"; I laugh, because we probably differ on that point to begin with...

Anyway, your original statement was "have you noticed weeds and wildflowers seldom if ever show signs of insect damage?"

IN general, most weeds are just plants, and many bugs/disease don't distinguish between weeds and cultivated plants.

However, there are exceptions. Introduced species often become prolific, sometimes so much so they are labeled invasive. Introduced plants didn't evolve with the local flora and fauna so sometimes they are not recognized as a food source by insects and the indigenous diseases don't grow on them either.

Cultivated plants often grow larger and more lush than non-cultivated plants, possibly making them more attractive to insects as well.

So your point has merit...but its not something that I have observed in my native landscape or my garden.

Peter, you haven't directly responded to the primary content of most of my posts in this thread. Instead you keep posting leading questions in support of your ideas; and in your post of Sat, Jun 7, 08 just above, you describe your ongoing questions as a hypothesis and observations.

Respectfully, questions and speculations and anecdotal observations are not evidence. Your assertion remains unproven.

All the best,
-Patrick

p.s. By the way, when I was growing up in the 1950s and 1960s, the standard flag of Canada in official use was the Red Ensign defaced with the shield of the Canadian coat of arms. The "official" flag of Canada was the Union flag, but it hasn't been flown over our schools or government buildings or carried by our troops for over a century.

Here is a link that might be useful: Canadian Red Ensign

What about the cedar apple rust (native) on my service berry (native) ten feet away from an eastern red cedar (native)? (Drat.)

joepyweed: how interesting that our exeriences differ. Our garden is also a native wildflower garden (southeast Michigan, particularly lush in May) among native shrubs and trees. And we don't have whit of insect pest or disease damage; touch wood, it might be dumb luck thus far. Animal damage is quite another matter. Have you considered what are you doing that attracts trouble?

alfie: I have a worse example: crabapples -- all their species (insofar as anyone can separate their species). But they keep on living and reproducing whereas a cabbage, say, would succumb.

madmagic: what do you think about Taino's idea? It's testable you understand. I remember that flag too.

Regards, Peter.

I'm not doing anything that attracts trouble, but I am attracting insects, loads of them. The insects are part of the bonus of growing wildflowers, not trouble. The bugs are attracted to the plants and the birds are attracted to the bugs. I'm trying to attract bugs and birds to my yard....

I detect scepticism about my hypothesis that weeds, unlike cultivars, don't suffer debilitating damage from insects or diseases. (I'm excluding wilflowers here because only some readers will have experience with them, whereas all readers have experience with weeds -- define weeds how you will.)

So I issue a challenge for anyone to come forward who has experience that confounds the hypothesis. To make it generally understandable I suggest you limit yourselves to the more common weeds that are growing in you area at this time. If there is damage, here in the Northwest it would be on lamb's quarters, red rooted pigweed, ground ivy, galinsoga, ragweed, great ragweed, Canada thistle, lady's thumb, yellow wood sorrel, yellow nut sedge, crabgrass, quackgrass, velvet leaf, and cocklebur. I know, because those are the ones I pulled today -- all healthy as fleas by the way.

And, if I do happen to be right there might be lessons here. Regards, Peter.

I am in the "confused by the difference between wildflowers and weeds" camp. I grow a lot of things on purpose that other people call weeds, and I call wildflowers. On the other hand, I have so much goldenrod in my yard that I always pull it out of my gardens, and I thus consider it a weed. Technically it is also a wildflower. Anyway, I have a LOT of it that is stunted, because it is a favorite target of whatever it is that goes around to plants and puts a milky colored frothy sticky substance with some kind of baby bug in it. The baby bug then eats at the plant while maturing. I have found this goop on a wide variety of plants but there is more on the goldenrod than anything else put together.

Hence I have significant insect damage on a native weed/wildflower. But not knowing if you call that a weed or not, I am not sure if I invalidate your theory or not. I have even seen creeping charlie with some sort of big lumps in the stem that suggested a creature had attacked it and laid eggs. Certainly creeping charlie is a weed. Alas, it did not spread enough to wipe out my creeping charlie. But it was really freaky looking.

Marcia

The most prolific uncultivated plant in my yard is some type of mercury (acalypha rhomboidea/virginica?) and its leaves have more insect holes in it than any other plant in my yard.

Even doing an internet search for the plant, its hard to find a picture of one without bug holes in it...

Every sowthistle (Sonchus oleraceus) in my yard has powdery mildew and is infested with aphids.

led zep rules, joepyweed, and dicot: excellent observations; I can't say I've had similar experience, but they confound my thesis. Have you noticed this though, that in the goldenrod case (bet it's Canada goldenrod) and the mercury case, these are still highly successful weeds despite insect predation. This says that the insect pressure hasn't disabled their reproductive "fitness" at all (which isn't the thing I was claiming of course). Here's an end on't, as they say. Regards, Peter.

I was thinking of you pete, yesterday, when I noticed the joepyeweed in my yard was not only full of insect holes, but some of the plants have a fungus growing on the lower leaves.

Its probably the worst I've seen, on that particular species.

There is no doubt whatever that in my gardens at least, "weeds" suffer less insect predation than the "cultivated" plants. And among the cultivated plants, "lush", lusty ones suffer less than more spindly ones.

Further anecdotal observation is that the more mix of plant species exist together - including weeds - the better from the perspective of reducing pest infestations.

I've seen lambsquarters ('midden weed' - great name for it by the way Peter, it is sprouting all over the thin layer of horse manure I applied last fall) affected by what looks like leaf miner. If anything, weeds have given me a lesson in allowing some insect damage to crops. But in general they do seem sturdier and more resistant.

I'm disappointed to see this perfectly good topic become contentious.

Was it contentious? I thought it was very civil.

I have tons of leaf miner damage on my columbine. I noticed the columbine at my brohter's house has so much leaf miner activity, you would think the plants were varigated.

I think another difference is that, though the damage is there, leaf miner damage is not as annoying on a plant that you don't plan to eat, compared to having leaf miner damage on a plant that you intended to eat.

It could be that our perception of weeds vs crops colours our perception of damage, ie we see damage more readily on those things we are carefully tending and anticipating a harvest from. But I also defer to Peter's gardening wisdom and many years of experience observing both weeds and food crops, which experience I have benefited from many times on these forums.