Use of fungicide and beneficials. Is there a middle ground?

14 years ago

I'm so tired of thrips so I am working on bringing beneficial insects into my garden. Living in hot and humid black spot is an issue. The more natural sprays, like baking soda just don't seem to do it. Does anyone spray fungicides and still have a healthy population of beneficial insects and worms? I won't spray insecticides.

nancy

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Comments (19)

zack_lau z6 CT ARS Consulting Rosarian
14 years ago
Yes, we spray fungicide only products. We also use granular Merit/Cyfluthrin for rose midge control. This results in enough beneficials to prevent spider mites. We also have lots of earthworms. A spider mite infestation is likely on anything sprayed with insecticides, unless it also has a miticide.
henry_kuska
14 years ago
See:
http://www.informaworld.com/smpp/content~content=a783868824~db=all

I was able to get the full paper. Probably the most interesting item is their Figure 9 which gives the results they obtained 75 days after spraying the rose "Edward". The no spray control had a "percent disease index of about 65, the chemical spray control (using Tridemorph) had a disease index of about 35, Pseudomonas fluoresens treatment had a disease index of about 45 and Trichoderma viride treatment had a disease index of about 40.

Here is a link that might be useful: link for above
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The damage from an over application of fungicide is to the soil microbes where the plant roots are. When the beneficial microbes are killed off, the plants growing there suffer. Those microbes are responsible for the nutrients your grass gets. You can also look for the soil to become extremely hard, not compacted, but hard. The soil can recover but not until all the fungicide is decomposed. Because of the negative effect on the soil, fungicide is one of the worst things you can apply to turf. It should be used with the most care. If this is St Augustine grass, there is an organic alternative which has worked for me every year since 2002. It seems to work for other types of grass, too, but it definitely works for me on the typical springtime diseases. The product is ordinary corn meal - yes the same stuff you cook with, only I get it at a feed store in 50-pound bags for the size and coverage I need. It cannot hurt your soil or grass...unless you completely smother the grass in it. The normal application rate is 20 pounds per 1,000 square feet. If you double that rate, no problem. If you quadruple that rate, you will know because you won't see grass anymore. Apply it, wet it, and let it work. Corn meal works through a biological process. First come the fungus species which decompose the corn meal. Then comes a predatory fungus called Trichoderma (try koh DER mah). The trichoderma wipes out the fungus growing on the corn meal and then looks for other fungi growing on the surface of the soil. The fungal disease is right there and becomes the next meal for the trichoderma. This process takes about 3 full weeks to see results. Corn meal is also a passable organic fertilizer. What this means is that if you only apply to the spots obviously affected by the fungus, those will turn dark green. To avoid having dark green spots in your yard, you should apply the corn meal to the entire lawn at the same rate. Corn meal will not work if you have already applied a chemical fungicide because the fungicide kills off the naturally occurring Trichoderma. Corn meal works on the most popular lawn diseases with the exception of any diseases characterized by red colors. So red thread and rust seem to not be affected by corn. At your feed store don't become confused by corn meal and corn GLUTEN meal. That is a different product and will have no effect on the disease in your yard. It is also much more expensive.
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It is a nice list, but I have companion planted forever and want to stress that it is far from a proven science. In fact, in multiple university studies, the companion planting claims do not hold up in controlled studies done to study their efficacy. I am at the point that I ignore all those comments about "improves growth or flavor" and I ignore 98% of the comments about any type of plant repelling specific pests. Very few of those supposed benefits have been observed in my garden, and I've been companion planting in this location ever since we moved here in 1999. The reason to companion plant is to attract beneficial insects, and that's why I do it. Here's one example from what I've learned over the years: I can surround my cabbage beds, for example, with a solid border of all the companion plants said to repel cabbage worms, and my cabbage plants (and all other brassicas susceptible to the same pests) will be totally devoured by cabbage worms anyway. 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Many other herbs will attract beneficial insects once they flower, and this includes catnip, catmint, lemon balm, sage, basil, mints (in pots only as they are incredibly invasive), borage, and wormwood. The beneficial insects that I most want to attract to my garden, in addition to bees of all kinds, are green lacewings, brown lacewings, hover flies, lady bugs, minute pirate bugs, big-eyed bugs, and all the little parasitic wasps like brachonid wasps, ichneumoid waspas, and trichogrammas wasps. The plants I listed above do attract them and I think the beneficial wasps, in specific, are why I don't have a lot of caterpillars anyway, notwithstanding the annual onslaught of cabbage worms. I believe the beneficial wasps eventually, in due time, would control the cabbage worms, but before that could happen, you'd have holey plants, so I just exclude them from the plants in the first place. You don't have to run out and buy tons of packets of flower and herb seeds. Many seed companies sell pollinator blends and good bug blends that attract bees and other pollinators as well as the beneficial insects I listed above. You can buy as little as one seed packet of pollinator or good bug attracting plants, or you can buy the mixes by the quarter pound or pound. I have used seed mixes like these from Peaceful Valley Farm Supply, Wildseed Farms and Botanical Interests, among others. Because many of the plants that attract pollinators are large, getting quite tall and spreading out wide, the easiest way to grow them is as border plants along the edges of your garden. You can choose smaller, more compact companion plants to grow in the same beds as your garden plants, but understand that even these can take up a lot of space if you aren't careful. It is hard enough to squeeze them into a large garden, and considerably harder to find space for them in small gardens. A lot of the herbs and flowers I grow to attract beneficials are grown as shorter border plants along the edges of raised beds or, if they are too tall to be true edging plants, I grow them at the ends of each raised bed, but not in the middles of the bed where the actual crop plants are growing. If you've ever seen a borage plant growing and spreading massively to try to outgrow the tomato plants beside it, you'll understand where I'm coming from. Of course, almost all my companion plants reseed readily, popping up anywhere and everywhere. I try to let them stay where they sprouted when I can, but if they start to outgrow the vegetable plants they're sitting next to, I either prune them back really hard or yank them out. I also grow tons of wildflowers outside the garden fence on all sides of the garden because they also attract beneficials. The area where most people fall short when planting to attract beneficials is that they fail to plan for the cool season. I have lady bugs, bees and other beneficial insects out even in January, frantically searching for food, so I do the best I can to provide for them. I always leave henbit wherever it pops up and let it bloom because so many beneficials depend on it in the cool-season. I have sweet alyssum and chamomile in bloom by February of most years and they attract many beneficials. I often have dianthus and violas blooming in February or early March. For early beneficials, you need extra-early plants to attract them and also to feed them. I never, ever, ever under any condition would consider ground ivy/Creeping Charlie to be a companion plant. It is a rampant, highly-invasive thug and I don't tolerate it anywhere. If you let it take hold and get established, you'll have it forever and it will be on a constant mission to take over every square inch of planting space, and it isn't just happy to occupy the garden. It will fight to stay in the lawn and in flower beds. Right now, if you walk out into my frozen garden, you'll still find green catnip plants (regrown since we dropped down to 4 degrees a few weeks ago), tansy and dianthus. You'll also find beneficial insects on them on all but the coldest days. You may not see the beneficial insects early in the morning on cold days, but you'll see them out by mid-day. When planting both cosmos and zinnias to attract beneficial insects, search out old-fashioned varieties that haven't had their nectar/pollen tampered with by modern plant breeders. Also, plant the shorter varieties that stay more compact and are easier to manage or you'll end up with huge cosmos and zinnia plants (easily attaining 4-5' in height) shading out surrounding plants. Same thing with nasturtiums. Grow only the short, busy ones, not the vining ones. While some of the more modern zinnias have tolerance of/resistance to powdery mildew bred into them and they look nice, they don't attract and keep beneficials like the old OP varieties do. I love companion planting and mixing in herbs and flowers with fruits and veggies all over the garden, but you have to manage the way you use companion plants or you'll find too much of your resources (soil, water, even light) going to them and not enough going to the edible plants you're growing. There are a few plants that make great trap plants, attracting pests to them. The way to use them is to grow them outside the garden itself in order to lure those pests away from the garden. Sunflowers are my favorite for this purpose. If you plant sunflowers outside the garden, maybe 10' from the garden, they'll attract stink bugs to them. Then, you can use the method of your choice to kill the stink bugs. Anything I can do to attract stinkbugs away from the garden in summer is worth doing. They are a horrible pest that feed on the fruits of most summer crops. The grain type amaranths are useful in this way to as they can lure some pests away from your garden.
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teka2rjleffel
Original Author
14 years ago
Thanks Zack and Henry. Henry it sounds like ( I couldn't open it) the article is talking about results of spraying vs not spraying and it's effects on how much disease the plant got. What about the effects on beneficial insects? Thanks for your help.
Nancy
henry_kuska
14 years ago
This is the abstract:

"Abstract
An attempt was made to study the biocontrol efficacy of antagonistic microorganisms in phylloplane of rose cv. Edward to manage the black spot (Diplocarpon rosae) disease. Eight antagonistic microorganisms were tested in vivo against the black spot pathogen. Among these, Trichoderma viride and Pseudomonas fluorescens pf1 reduces the mycelial growth significantly. These two biocontrol agents were evaluated for their ability to induce defense-related enzymes and chemicals in plants. Increased activity of phenylalanine ammonia lyase (PAL), peroxidase (PO), polyphenoloxidase (PPO) and total phenolics were recorded in all the biocontrol agents treated leaves. P. fluorescens Pf1 recorded early and increased synthesis of the entire defense-related enzymes and total phenol within 6 days. The application of biocontrol agents induced the defense-related enzymes involved in phenyl propanoid pathway in addition to direct antagonism, which collectively contribute for enhanced resistance against invasion of Diplocarpon rosae in rose."

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I do not see how benefical insects could affect a fungus.
Zyperiris
14 years ago
Well these guys have all the science..let me tell you what I have learned after one year of trying not to use harsh chemicals. When you need to use something for disease..try something just for the disease..not a bug killer at the same time..Try and treat or ignore the disease..or use something mild. I have learned not to expect perfection with the leaves..I can live with bugs..but the BS gets me. I am trying very hard to embrace organics. I think if you are aware of what you use and don't go get the strongest chemical on the market that kills all bugs and diseases you are ahead of the game. Also I have attended many rose lectures here and many many of the experts go organic..that means something to me. Work on getting the soil healthy and let the bag bugs stick around long enough for the good bugs to show up
roseseek
14 years ago
Spinosad - ORGANIC bacterial effective against chewing insects AND thrips. Lower effects on beneficials.

http://www.agorganics.com/products/Spinosad-Lawn--Garden-Spray--16oz-Conc--Green-Light/12/220.html

Serenade - ORGANIC bacterial fungicide.

http://www.serenadegarden.com/
buford
14 years ago
If you use a true fungicide, not one that also contains an insecticide, you should be ok. I regularly spray with Bayer Disease Control which is only a fungicide and have many insects including minute pirate bugs that eat thrips. However, I still get thrips :( I stopped using insecticides a few years ago (I used to use the Bayer drench that was feed, disease control and insect control) and since not using it have seen many more insects and worms. Including, unfortunately, thrips. The only thing I will spray for, if I have a deluge, is Japanese Beetles. But I haven't had many the past 3 years, knock on wood.
henry_kuska
14 years ago
Antitranspirants have not been mentioned.

One example where antitranspirants are mentioned plus a good collection of other treatments:

http://www.bbg.org/gar2/topics/sustainable/handbooks/naturaldisease/leasttoxic.html#s1f

Here is a link that might be useful: link for above
teka2rjleffel
Original Author
14 years ago
That's exactly where I am Buford. I use Bayer Disease Control and it works great on BS. My concern was that from various things that I have read that chemical fungicides harm the beneficial insects. It sounds like your results Buford don't agree with that. I have decided to sacrifice the summer garden to the thrips and won't use any insecticide, natural or chemical. Maybe if I leave a big feast of thrips for the beneficial insects they will hang around and I can get some natural balance back. I'm planting plants like dill and fennel to attract and keep them in the garden. If the Bayer Disease Control doesn't harm them I'll just keep using that.
Nancy
texaslynn
14 years ago
Nancy, I have to spray off and on (fungicide only and I also use the Bayer product) during the spring and fall (humid, humid, humid here - but gets hot enough in the summer to suspend spraying, thank goodness).

There is a lot of debate about this but in my experience, I haven't killed too many bugs, if any, good or bad, with fungicide. I have billions of thrips and aphids, much to my despair. I have millions of those beetles (from grubs) and they munch away quite nicely at my roses......it doesn't seem as if the fungicide has killed a single one of them, doggone it (I know I have looked around my flowers after spraying and I have never seen anything dead). The day after spraying, the thrips, aphids and beetles are all just as happy as if I hadn't done a thing. I have a lot of those large green spiders living on the plants (they come out a little later).

The fungicide wouldn't kill just the good bugs and leave the bad, it would kill them all. And along with all the bugs that ruin my blooms, I have ladybugs and bees and bumblebees and butterflies and walking sticks and preying mantis and birds in abundance. And millions of earthworms and healthy soil and lots of sun and openness...BUT I also live in a climate that encourages BS in a major way at particular times of the year and I do like to have foliage to go with my flowers! Unfortunately, all my composting and organic fertilizers and other eco-friendly methods that I adhere to don't seem to mean much to the BS spores when the temp/humidity around here hits that ideal range for the disease's growth. So I reluctantly get out the sprayer and spray very carefully and as few times as I can get away with.

I feel your pain with the thrip problem; they always ruin most of my lighter colored blooms and I just live with it - grrrrrrr. But I'm not going to surrender my garden, that I work so hard in, to BOTH bugs and BS. One of them has gotta go and I picked the fungicide as the lesser of two evils.
Lynn
Zyperiris
14 years ago
You guys said it better than me..Start with small ammo..don't go for the entire US military when a Boy Scout could do the trick
teka2rjleffel
Original Author
14 years ago
Lynn you make a great point. If the fungicide killed bugs it would kill the bad guys as well as the good guys. I would need to spray more often than once in a while here. It rains nearly every afternoon around 4 and is really humid all of the time. But I am encouraged by your bugs, birds and worms. I'm not giving up my garden entirely. I am just not fighting the thrips for this summer and hope that the invitation gets sent to the good bugs. I'll enjoy my tropicals this summer and enjoy the roses in the full and winter. It's a nice advantage is have a 12 month growing season.
I hear ya Zyperiris. I'm trying to do none and the disease troops are advancing on me. But I'm going to bring out one sniper (Bayer Disease Control)and hope for the best.
elemire
14 years ago
Well it also depends on how do you spray. Generally I tend to plant a few more sensitive roses in one place, so I can spray that small plot when I need to - but I have maybe 5 roses for such treatment, so area is quite small. Even if I spray it with insecticides, it does not seem to have a general effect on my whole garden, in which I do not use insecticides and only fungicides.

Also in my personal opinion, most commercial organic sprays are really a waste of money, over the years I have tried quite some and there was almost no to absolutely no difference if I used those or just left nature to sort things out. Also, what works better than most organic sprays is to gather all the bad guys manually - it is tedious and tiresome work, but it rather effectively cuts on the numbers of population, especially if done systematically before bad guys multiply.
teka2rjleffel
Original Author
14 years ago
Elemire, I sure wish I had thought to group more disease prone roses together, but I didn't. They are scattered around. In the end I may just end up shovel pruning some of the worst disease prone ones. My sister picks her Japanese Beetles off into a bucket of water. Fortunately we don't have them. But I can't even see the thrips which are my major pest and even harsh chemicals don't work on them for long. They adapt quickly. I have a few roses that don't seem to be appealing to them. There are days when it makes sense to me to dig all of the others out and replace them with the few that the thrips don't like. But I would have 20 each of the three that aren't bothered. Kind of boring.
Nancy
henry_kuska
14 years ago
The following is a Google search using the keywords antitranspirant and thrip:

http://www.google.com/search?source=ig&hl=en&rlz=1R2IRFC_en&q=Antitranspirant+thrip&btnG=Google+Search&aq=f&aqi=&aql=&oq=&gs_rfai=

Also see:
http://www.google.com/patents?hl=en&lr=&vid=USPAT6464995&id=soUKAAAAEBAJ&oi=fnd&dq=antitranspirant+and+thrip&printsec=abstract#v=onepage&q=&f=false

Here is a link that might be useful: Google search mentioned above
susan9santabarbara
14 years ago
Fungicides control fungal diseases. They have absolutely no effect on insects, harmful or beneficial. Fungicides and insecticides are two completely different products that do completely different things. Your only concern about a fungicide killing beneficials would be if you use a product that combines the two (not a good idea).

Susan
henry_kuska
14 years ago
Susan9santabarbara, it would be nice if your statement applied to all fungicides and all beneficials, but unfortunately each fungicide must be evaluated separately for each benefical.

The blackspot fungicide treatment that most appear to be using contains tebuconazole. The link below is to a 2007 paper concerning a beneficial that attacks aphids.:

http://www.ncbi.nlm.nih.gov/pubmed/18399430

Here is a link that might be useful: link for above
henry_kuska
14 years ago
Friendly fungi can control aphids. Tebuconazole "takes care" of the blackspot but also "takes care" of the friendly fungi.

"Other products reduced infectivity by between 50% and 100%. These are, from the least to the most toxic:flutriafol, prochloraz, epoxyconazole, iprodione, hexaconazole, triadimenol, azoxystrobine, cyproconazole, cyprodynil, flusilazole and tridemorph. Chlorothalonil,fenpropimorph, spiroxamine and tebuconazole totally inhibited infectivity of the fungi."

http://www.springerlink.com/content/45hpt4gy854rb7c2/

Here is a link that might be useful: link for above
dennisb1
14 years ago
I spray with only Fungicides and have no problem with beneficials. I say this because the only real insect pest i have is years when the Japanese beetles are around. Other than that I make have an outbreak of rose slugs which, if bad enough I will spot treat with Sevin. I also have tons of bees.

I don't think Fungicides bother insects.

Use of fungicide and beneficials. Is there a middle ground?

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Use of fungicide and beneficials. Is there a middle ground?

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