fall pest patrol: work now to foil deer, cabbage worms, viburnum beetle, squash bugs, voles

fall pest controlTHE MOST IMPORTANT SUBSET of the fall garden cleanup chores: pest control. Fortunately all our needed cutbacks and raking of leaves–those sanitation efforts we’re all heading out to do, anyhow—help to reduce places for many garden pests to overwinter. But I go farther in areas where outbreaks have occurred. I work to prevent a buildup next year of targeted troubles like viburnum leaf beetle, squash bugs and borers and cabbage worms, and minimize damage by deer, mice and voles. The routine is the same in every case. What it comes down to: Eliminate habitat and hiding places for the specific pests where they occurred, and eliminate some of the population. Pest by pest, some particulars:

cabbage worms

I HOSTED A cabbage-worm field day here one recent year, apparently, and squished eggs and larvae like mad. Now I’ll be certain to clean up any cruciferous plants extra-carefully, to reduce the chance of overwintering pupae, and am reading up on weeds in the cabbage family (wild mustards, for instance, and shepherd’s purse, among others) with a sterner eye to their removal, too.  Because kale and Brussels sprouts are so cold-hardy, and stand a long time into the winter garden for gradual harvesting (until Thanksgiving or longer), I have to be sure to pull the remains when they are done this year, even if it’s tempting to let some overwinter. The whole cabbage-worm story is here.

viburnum leaf beetle

SCOUTING FOR viburnum leaf beetle starts in late October here in Zone 5B, when leaves fall and their egg cases laid on this year’s viburnum growth are easier to see. Remove egg cases by pruning off affected wood, between now and April-ish, to reduce larvae and beetle issues in the coming year. The bump-like cases are usually on the underside of youngest twigs. I then also watch in May for larvae hatch (left) of any I missed, and rub the twigs then to squash the emerging pests.

I check every Viburnum, of which I have many species and varieties, but only a couple of cranberrybush types typically show any leaf damage, and now have egg cases. But why only those? Apparently there is natural resistance in many species, and you can get the list here if you wish to grow Viburnum but not ones that the beetle adores.

squash bugs and squash vine borers

THE KEY TO MANAGING squash bugs is to not let them build up—meaning vigilant egg removal in spring, and handpicking of adults, but also strict cleanup in the fall to reduce overwintering of unmated adults.  The same is true of squash vine borers, which overwinter as larvae or pupae. Debris from all squash relative plants should be removed (some people burn it if there was a bad infestation). Best would have been to remove it right at harvest time, not just cutting the fruits and leaving the vines until garden cleanup later.

Other hiding places such as rocks, boards and such must also be moved aside. A rough turning of the soil may dislodge some pests, exposing them to predation by birds or other animals. All of this must be followed by prompt attention in spring, when young plants are especially susceptible and insect populations are rising. Growing a resistant variety, such as ‘Butternut,’ is helpful, especially if you had a recent problem. The full squash-bug story, and a thorough pdf factsheet from the the National Sustainable Agriculture Information Service provides more information on both of these pests of Cucurbits.

If you have issues with cucumber beetles, whose unmated adults also like to overwinter in plant debris and beneath other material on the ground, following the same sanitation practices can help.


KEEPING DEER OUT, or choosing plants that are somewhat less palatable for the areas where you cannot bar them, was the topic of a recent podcast. I’m not a big believer in “deer-proof” or even “deer-resistant” plantings as enough of a defense; I believe instead in fences, and my full rundown on creative ways to fence (some of which are not so ugly) is in the article on just saying no to deer with fencing. In fall, before any snow flies, it’s critical to check the fenceline for any breaches (something I do regularly), and also for any overhanging limbs that might better be pruned now rather than risk having them fall in winter, damaging my deer barrier.

No fence? Unprotected shrubs and trees with branches low enough to be in deer-browse height range can be sprayed with a repellent containing putrescent egg solids and capsaicin (the heat in hot peppers), and individual garlic clips can be added to branches. But exclusion is even better–even if it’s  just around individual plants. Ohio State’s wildlife expert Marne Titchenell gave me a 101 on her tactics for outsmarting deer.

mice and voles

I LEAVE my small meadow above the house unmown in winter to benefit other wildlife, so I have to deal with more mice (and voles) than I might otherwise. Close cutting the lawn, with special care to clear weeds and turf around the trunks of woody plants, is just one possible step in this heroic battle against these small but voracious rodents. Mice are also an important link in the Lyme Disease chain, so I have zero tolerance of them getting indoors. Installing hardware-cloth or plastic tree guards is another—and so is trapping, which I accelerate my efforts at starting in late August.

I have some tricks—including an idea for a box (above left photo) built to enclose mousetraps that I borrowed from sustainable-agriculture expert Eliot Coleman—all of that is covered in this article.

Critical point: Never use highly toxic mothballs for rodent control or any other unregistered application.

A note on a larger mammal, the rabbit (who I am reminded is a lagomorph, not a rodent): They’ll browse woody plants in winter, too, and relentlessly. As with deer, I think they are best controlled by fencing, using 48-inch-high mesh no larger than an inch diameter, burying it about a foot with the rest above ground, supported with stakes or posts. Ohio State’s wildlife expert Marne Titchenell gave me some tips for outsmarting them, too.

An aside on moles (who are not rodents but insectivores): They can be frustrating with all their tunneling, yes, but they aerate the soil and eat grubs, so I generally celebrate their activity (well, after cursing every now and again when they uproot some lovely thing in the process of hunting food). I had long believed that reducing grubs (such as those of Japanese beetle) in the turf and beds would reduce their food source and therefore discourage the moles, but various experts including Purdue say this is not true, because earthworms are their primary food.

Are there pests you’re working to get ahead of for next year now?


    1. LB says:

      Here in Putnam County NY I have V dentatum, V prunifolium, V tirlobum, V acerifolium and V rhytidophylloides. The dentatum and prunifolium are decimated every year despite my efforts to remove egg casings in late winter and all the hand picking I do in the summer with larvae and then the adult beetles. The other species have not, yet, been effected. I didn’t know about VLB when I planted them; I would have planted something else if I had known. I wish nursery tags contained such information!

  1. Nora says:

    Thanks for all the tips. One more from a friend who professionally bands migrating birds. She recommends holding off on clearing leaf litter and “stuff” in the garden beds til migration is well and truly over. Apparently this is a prime area for birds like wood thrushes to rummage for food on the road south. So we hold off til that long Thanksgiving weekend, when we give thanks for a lovely year of the garden! Battening down our hatches here in NJ where the weather is bad, bad, bad! (But I get to stay home and read gardening stuff! WooHoo)

  2. Carole Clarin says:

    As the wind whistles outside, blowing yet more leaves around, it’s a good time to do some indoor clean-up that has been neglected due to all the outside work. Maybe if the power holds I’ll make some more soup and applesauce!

  3. Miriam says:

    Weathering the storm in NYC and it’s really not too bad here. Thinking about my gardens in the Berks and feeling better about not having cleaned up my garden yet thanks to one of your responders.
    Stay safe!

  4. Bob says:

    Lily beetles. Growing many more lilies in the new garden than previously, and it was a banner year! Following your advice and monitoring the foliage daily really reduced the damage drastically. I quickly lost any sqeamishness about squishing the beetles when I remembered how disgusting the larvae are. Love the foliage this time of year as it colors in the fall, but I’ll be sure to clean up meticulously when they’re ready to go!

  5. jessica says:

    What can you tell us aout gophers, Margaret? I don’t kill animals so I would like any advice other than that.

    From your book, I know hoe you feel about storms, so I hope you are ok.

    1. margaret says:

      We don’t have them here, Jessica, but prompted by your question I read this archived article from the SF paper on nontoxic control, and UC Davis Extension’s information here, but of course as with other animal pests most of it involves trapping. Note that in the UC Davis piece it does talk a bit about making the habitat less desirable (similar to how I have to be sure to mow short and remove all grass/weeds around tree trunks here, etc.).

  6. Lorie says:

    Am sending buckets of prayers your way re Sandy. We went through one of those a few years back; no power for 2 weeks; hundred year old trees down on roofs; Halloween cancelled (which was the least of anyone’s troubles)…you just feel like there’s no light at the end of the tunnel. But there is. Take care.

  7. Mary Jane says:

    Any ideas on getting rid of slugs in the fall? What’s their life cycle?
    I’m still finding them under outdoor pots and saucers, and just around. I searched and purged all summer. For baseball fans, I feel like I’m Detroit and they’re San Francisco!

    Hope everyone made it through Sandy; gardens help restore us.

  8. jessica says:

    Thank you so much for that research, Margaret. You don’t have Gophers!? Lucky you! I have found some interesting no kill solutions. One is Gopher Baskets and I have dug up the whole garden and replanted in the baskets. They
    protect the plant root ball, and I have so many that tunnel digging is now quite a chore down there (but they still manage). I also flood the tunnels when I can find openings, and they run out the other exits. Today a first – I actually saw the little bugger run out and I chased him out of the garden with the hose! Used cat litter clumps make nice door stops too. I am in Santa Fe and we don’t have fleas, snails, slugs, or mosquitoes, but lots of gophers!

  9. Lynda says:

    Anything further you can suggest for the fall to rid the lillies of the little red beetle and larve after a difficult summer of trying to remove them .
    In addition, any thoughts on my other favorite flower delphiniums who get this black pasty stuff on the flower bud and leaf. I removed some older infected ones but saw some sign of recurrence on my newer ones.

  10. Dawn Mathewson says:

    We put straw down in the vegetable garden for the first time to help with weed & moisture control. Worked out beautifully. We had a problem with powdery mildew & squash bugs.
    My question is, do I leave the straw through the winter or rake it up now & dispose of it?

    1. margaret says:

      Hi, Dawn. Nature abhors a vaccuum — ever heard that expression? Meaning, in this case, bare soil is an invitation to weeds galore — all the seeds in the soil or that blow in sprouting with exposure to light. That’s who planting cover crops, or leaving mulch in place, is preferable to bare soil. I leave the mulch in place, but one caveat: I keep an eye out for rodents in case they decide it’s a great hiding spot. I leave traps in high-traffic spots that I discover, like this.

    1. margaret says:

      Hi, CC. Similar to the approach to squash bugs, really, since adults overwinter in the plant debris and elsewhere. Here is some expert advice:

      “[Crop] rotation does not control this pest very effectively, because cucumber beetles are good fliers, but sanitation can help a great deal,” says Maine Organic Farmers and Gardeners in this report. “Keep the area around your fields mowed and free of trash. Plow down plant debris in the fall and plant a cover crop. Floating row covers make a great barrier that will keep the plants free from the pest, at least until the crops flower. Then you have to remove the covers to allow pollinators access. Remember to weed under the row covers, as these fabrics promote plant growth.”

      High Mowing Organic Seeds has an extensive article on chemical-free control as well, at this link.

  11. Linda hall says:

    I’ve been told by one of my neighbors, that fallen birdseed for feeders will bring a host of gophers. I haven’t had that experience, wonder if others have made that connection. My sister swears it’s true!
    My biggest problem this past summer was green looper caterpillars. They were eating everything, even my tomato leaves.I finally got some BT….that helped, but too little, too late it seems. The basil is all but gone. But, next year I’ll be ready!

  12. Amanda says:

    Grasshoppers! Just finishing the chicken coop. I’ve heard the chickens will eat them while they are small. For the other three million of them I don’t know. Maybe we won’t be so dry next year and they’re wont be so many.

  13. Margaret, the link to the pdf on squash bug control for fall leads me to a Maine.gov site on pesticide management. I would LOVE to read a “thorough pdf factsheet from the the National Sustainable Agriculture Information Service,” but alas, it’s not there. Can you re-post a direct link to the pdf? Many thanks for your wonderful newsletter, which keeps me on the straight and narrow when it comes to the garden tasks I should be doing right now.

    1. margaret says:

      Here is the link. I just did a fast search for squash bug and National Sustainable Agriculture Information Service, and voila! Sadly websites update themselves and don’t add what are called “redirects” to make sure old links go to the right places.

  14. Carl says:

    I’ve gardened for 30 plus years and each year I almost always learn something new.

    This year it concerned Japanese Beetles. They’ll kill a rhubarb plant if you don’t deal with them quickly. So I tried an experiment.

    I killed several of them by hand and smeared their remains on the rhubarb leaves. My rhubarb was being attacked by dozens of them. Within 10 minutes the survivors diaappeared and did not come back for at least two weeks. For the rest of the summer each time I’d see a beetle near my rhubarb I’d repeat the process.

    There is a downside to this. Dead Japanese Beetles STINK. Be sure to wear rubber gloves so the smell does not stay on your fingers.

    So where did the survivors go?? Most of them wound up in my beetle trap. Each time I did this proceedure I had to empty the beetle trap daily.

  15. Choral Eddie says:

    I have numerous potted containers on a deck, off the ground, that hosted veggies and flowers over the summer grown from seed in my basement with bagged organic starter soil. The soil in the deck pots was also bagged organic soil and compost. I was careful as I wanted to avoid getting the invasive Asian “jumping” Earthworm that has taken over the ground soil on my property for the past four years. However, in preparing the deck pots for winter storage I’m discovering that several of the pots contain the invasive Asian “jumping” Earthworm. Are we to assume that buying bagged organic soil may come with the eggs or even worms of the Asian Earthworm? It would seem so…

  16. Cynthia Tarail says:

    Margaret, thank you for this. Two questions: 1. When voles (I am thinking it’s the voles) are detaching Oriental poppies, parsley, and even onions from their tops, well away from grass you’re encouraging mowing, what can you do? 2. Will moles eat the snake worms? The worms are writhing throughout my yard and garden. They’re even right on top of the grass. My vegetable garden soil is like coffee grounds and when it’s dry, powdery, despite all the mulching, amending, and green manuring. Are there any other predators of them yet?

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