You Bet Your Garden

How to protect your neighborhood from unwanted pesticides

Listen to the full show:

Mike explains how to rid your lawn of clover, which pear trees are the best to plant, how your lawn care could be killing your trees, why the genetically modified issue is an herbicide issue and how to protect your neighborhood from unwanted pesticides.

Question of the Week:

“A friend recently called my attention to the fact that our township sprayed weedkillers from a truck along the side of a stream at a local ball field. The vegetation was brown and wilted for quite a distance, and a wide variety of plants seem to have been affected, including a neighbor’s arborvitaes on the opposite bank. A dog was nosing around in the water, and I noticed a couple of dead frogs. There is also a playground about 100 yards downstream. Is this safe? If not, what can I do about it?”

— Larry in Bucks County, PA

How to protect your neighborhood from unwanted pesticides »

Highlights from show for September 14, 2013:

Rid your lawn of clovers

Sandy from Flower Town, Pennsylvania is hoping to find an organic way to eliminate white clovers that are disrupting the green of her lawn. Mike offers a surprising twist that clover was actually an integral part of every grass mixture up until the mid 1960s, as it is a source of nitrogen and can actually feed the lawn if the clippings are returned after mowing. However, Mike explains, having a proliferating clover problem is a general sign that the lawn is under fed and/or over watered. ” But if you’re not over watering and you get on a good feeding schedule (once in the fall, once in the spring, never in the summer, just twice a year) and you still see the clover, then one of these upcoming falls you should have your lawn aerated. That’s running a machine over it to pull little plugs out, and that’ll relieve the soil compaction. Your lawn will drain better. And then the amount of water it gets becomes less important because the soil compaction is less and the roots can take it up and use it. “

Picking the right pear tree

Mike from Winterville, North Carolina has a Bradford pear tree he wants to replace, considering the many problems it produces. Inundated with the many varieties of trees, he phones in to ask Mike which trees grow well in a yard. Taking into account that the caller is blind, Mike offers this suggestion: “If you have somebody to help you with the pears, then you’re going to have that taste and know you grew it on your own property. Because pears really do grow themselves.” Mike goes on to say, “If you’re going to grow a fruit tree, and you want something to eat, a disease resistant pear would be the absolute right thing to do.”

The genetically modified issue is an herbicide issue

Doug, a scientist from Newark, Delaware, is concerned about the misplaced caution for genetically modified foods. Prompted by a previous call regarding the dangers of using genetically modified foods in composting, Doug calls to talk more in depth about the true culprit behind the health concerns of genetically modified (GM) foods: herbicides. Mike, being an organic advocate, explains that although there might be little genetic difference between GM foods and organic foods, GM foods are modified to tolerate systemic weed killers that are then ingested by people. This increased use of herbicides is undoing the potentially useful advances of GM foods. Mike says, “When GM crops first appeared, the promise was that they would increase yield and reduce pesticide use. And so far the main, the most popular genetically modified crops, the roundup ready ones (the roundup ready soybean and corn), they’ve dramatically increased the use of an herbicide that some researchers have linked to the killing of amphibians and especially in the egg and tadpole stage.” Mike just doesn’t believe that Genetically Modified foods fulfills the original promise of reducing pesticide use.

  • Related: Tim Mountz on GMO’s

“When GM crops first appeared, the promise was that they would increase yield and reduce pesticide use. And so far, … they’ve dramatically increased the use of an herbicide that some researchers have linked to the killing of amphibians.”

Mike McGrath

Caring for your lawn could be killing your trees

Vern from Akron, Ohio has a crab apple tree that’s going in a flower bed surrounded by a lawn. The tree has always been healthy until a few years ago, when the leaves started falling off after the flowers bloomed, and would become completely bare by June. Vern has been fertilizing his lawn for the past five years by following a four-step program put out by lawn care companies, but Mike advises against this. He says, “These four-step programs are bad for lawns. If you feed your lawn in the summer your lawn is going to have brown spots, bare spots, and lots of problems. You should feed your lawn naturally in the spring and in the fall. Because the tree is so close to it, the feedings you give your lawn are going to affect the tree. So you want to keep cheep chemical fertilizers away from there.”

  • First Officer

    Recently i hear your discussion about GMO’s and weed killers and hw they encouurage massive use of herbicides. You also mentioned that GMO’s have allowed the use of Roundup, glyphosate, to be more specific, that has been linked to toxicity in amphibians. It is true that glyphosate carries some toxicity for amphibians. It is also true that glyphosate is much less toxic to fish, fowl, mammals and amphibians than the herbicides that GMO’s have allowed glyphosate to replace, such as Altrazine. You also did not mention at all the Bt GMO’s which have allowed the foregoing of much use of broadband insecticides. You could have also mentioned Golden Rice, a set of GM rices that have been modified to have beta-carotene and iron. These rices will help combat Vitamin A deficiency throughout the world which claims hundreds of thousands of lives a year.

  • First Officer

    Ther is another thing you mentioned about GMO’s that isn’t really true. That is it stops seed saving. While it is true that famrers do have to abide by the contract of using patented seeds and not save them, commercial farmers haven’t been saving seeds for many decades now for such things as corn. They don’t because they find buying the then hybrid and now GM seeds produce superior results over saving seeds. If they didn’t, farmers would quickly go back to what they bought before. Farmers are pretty smart, afterall. Farmers buy, rather than save, seeds because they can see they get real world benefits from doing so.

  • Jim Corrodi


    My neighbor and I share a hedge (I believe it is a yew) about 3ft high, 3 ft wide, and 40 feet long. It has been in place since long before we moved here 7 years ago, and 95% of it appears extremely healthy. However, two strips about 2 ft wide from the ground up to the “shoulder” of the hedge have turned yellow and then brown (obviously dying). Each of these dead strips is directly across the hedge from each other (i.e., one on my neighbor’s side of the hedge and one on our side), with about 1 ft of healthy-looking dark green hedge separating them in the middle (of the top) of the hedge. [If you give me your email address, I’d love to send you a picture.]
    Do you have any idea what might be causing these two strip to die (in the middle of a healthy hedge)?

    • Sarah Kaizar

      Hi Jim — I shared your question with Mike and he can’t offer a quick answer with the information you provided. He would like to know: “Have you been feeding them? If so, with what? Are they mulched?If so, with what? Are they growing in or near a treated lawn? And how do you water?”

  • biorat 484-318-3789

    Your problem is, most likely, that apple scab fungus is defoliating your crab apple tree. Many crab apples varieties are very susceptible to this scab and loose most of their leaves by late summer, especially in years with a lot of rain; as we have had this year in the mid-Atlantic region. The same goes for apple fruit trees, though they generally don’t defoliate so severely. It is not related to lawn fertilization; except as it relates to whether the infected leaves overwinter or decompose; thus stopping the scab fungus infected leaves from releasing spores in spring and beginning the cycle anew. Rake up and compost all falling leaves to destroy overwintering fungus which reinfects the tree next spring, during rainy periods, just as the new leaves begin to grow out. Spray with a good compost tea weekly, [Holganix is a commercial brand with distribution up and down the east coast, to lawn service providers; it is shelf stable for a year if kept in a refrigerator]. Start spraying at 1/4″ green, and continue until June or spring rains subside, this will help to protect new leaves from infection. Then again in fall at leaf drop, when half the leaves are off the tree (assuming they stay on that long) , spray the tree and dropped leaves on the ground, add a nitrogen source such as manure tea or urea to the spray, or spread corn gluten on the ground(lawn) around the trees. Follow with a mower set low to chop the leaves and grass; this will help to decompose the leaves and thus reduce or prevent overwintering scab fungus from developing spores in the spring to reinfect the tree.
    Adding a liquid seaweed to your sprays (diluted 500:1) and spreading kelp meal on the ground (1/2 lb. per 100 sq. feet) will help the tree to resist infection also, and make it much healthier over all.
    In 2 or 3 seasons you should be able to get the scab reduced to tolerable levels or nearly eliminated.

    • Sarah Kaizar

      Hi DanL — I shared your comment with Mike to see if he had anything to add to the conversation, and this is his response: “Apple Scab is certainly a possibility–and one I probably should have mentioned–but I don’t endorse any of these proposed remedies other than excellent sanitation (the need for which I agree with 100%) and maybe a mulch of real compost. To my feeble mind, excess nitrogen would make the problem worse, modern urea is a pretty nasty chemical fertilizer, and I am impossibly suspicious of ‘shelf stable’ compost tea. But the disease possibility is itself an excellent thought. Thanks, DanL…. “

  • Les from East Detroit, MI

    Mike, I am a 6 year Gardener. In Fall of 2011 I Planted Heritage Raspberries “Everbearing” which are Certified Stock from a reputable Seed Company. It is September 2013 and I am starting to get some decent production. I have noticed throughout the Season something has been chewing elongated holes in the Plants Leaves. Also I see many Ants crawling in and out of Pinholes which have been made in the Fruit. What type of Pest or Pests could be the suspected culprits and what can I do to prevent Fruit loss and Plant Damage as well? Thank You Mike and I enjoy listening to You Bet Your Garden and appreciate your knowledge.

    • Sarah Kaizar

      Hi Les — I passed your question on to Mike and he advises: “Read the articles on raspberries at our site and check for small white (Asian fruit fly) maggots in the ripe berries…” Mike had a recent caller with this latter problem; you can listen to this conversation in the post titled “Don’t let stinging insects get the best of you!” Good luck, and thanks for listening!

  • Kathy

    RE: Concerned for the Honeybees


    I live just north of Philadelphia in a 49-unit Over 55 Community run by a Homeowners Association. Our landscaping services include fertilizing and weed & grub control. In addition to fertilizer (Turflo Plus Liquid Fertilizer), our spraying includes Prodiamine (crabgrass pre-emergent), Triplet SF (broadleaf weed control), and Imidicloprid (preventative grub control).

    The MSDS on the grub control clearly states “highly toxic to bees exposed to direct treatment or residues on blooming crops or weeds.” I requested that it not be sprayed at least in the area where I live, but some Board Members are hesitant in granting my request because they feel stopping the application will cause the lawn to degrade & result in costly repairs.

    Any suggestions on how to handle my dilemma?

  • Trisha

    It was mentioned by Kathy that she is concerned about the honeybees and the effect of fertilizer on them. Isn’t clover a good thing for honey bees? I see it as still green with a little white. So I will tolerate it for the bees sake. There was a big article in TIME magazine a few months ago about how important bees are and how hives are dying off at an alarming rate due to chemicals.

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