3 keys to battling your winter moth infestation

If you noticed ugly grey moths flitting around your property in late November and early December, I have some bad news for you — you have a serious bug problem that will erupt in about a month.

But there are some things you can do about it, and that’s what we’ll talk about in this week’s blog.

Those bugs were winter moths, a European invasive species that has been steadily chewing its way through the Northeast United States and Eastern Canada. Their offspring hatch as tiny green worms in April, and they’ll emerge by the millions — as many as 250,000 in a single large tree.

Here are some telltale signs that you have a winter moth infestation:

  • Lots of moths flying around your property at night in late November/early December.
  • Dozens (or hundreds) of tiny lime-green worms hanging from silk-like strands in April and May.
  • Cars and outdoor furniture covered with tiny black pellets in April/May (this, I hate to say, is their poop).
  • Leaves on your maple, ash, and flowering trees chewed heavily, if not completely denuded.
  • No fruits on your fruit trees and blueberry bushes.

They love to eat all sorts of flowering trees and bushes — crabapples, apples, plums, cherries, and blueberries, to name a few (they don’t seem to like peaches or raspberries…hmmm…). They also eat the leaves of maples, ash, and many other hardwood species of native trees. They’ll wipe out the buds on these trees and bushes when they are most vulnerable — when the buds are swelling and starting to blossom. They will wipe out your fruit crops and do serious, potentially deadly, damage to your trees.

This is the time of year when you can start to fight back. They’ve laid their eggs in the bark of your trees, and so they are somewhat vulnerable. Winter moths don’t have a natural predator here in North America to keep them in check, so it’s crucial to take steps to reduce their numbers.

There’s a two=phase strategy you should employ.

Phase 1 –Dormant oil sprays and insecticidal soap

Before your trees start to break open their buds, you can apply sprays that will kill at least some of the eggs that winter moths have laid on the bark.

Spraying your trees isn’t as much of a hassle as it sounds — as long as they are fairly small trees, like no taller than 10-15 feet. If they are taller than that, I’m afraid they’re a lost cause (but there’s some hope — see Phase 3).

You can buy a 2-gallon spray can for about $20, and the  ingredients for dormant oil and insecticidal soap compounds are cheap and easy to come by.

Here are a few recipes:

RECIPE 1: 2 tablespoons of ultrafine canola oil and 1 tablespoon of baking soda mixed with a gallon of water.

RECIPE 2: 2 tablespoons of horticultural oil, 1 tablespoon of baking soda, 1 tablespoon of kelp and 1 tablespoon of mild dish soap mixed with 1 gallon of water.

RECIPE 3: 2 tablespoons of baking soda, 5 tablespoons of hydrogen peroxide, 2 tablespoons of castile soap and 1 gallon of water.

You should apply the spray when the trees are dry, and the temperature is above freezing. These sprays can potentially do some damage to the tree itself, so you need to be careful.

These sprays will apply a thin film that will suffocate the eggs, but I’ve found they aren’t terribly effective on their own. Winter moths are clever at laying eggs in crevices and nooks that make it hard to get a solid dose of spray on them. Still, you’ll  put a dent in the population, and that’s good.

Phase 2 — Organic bacteria spray

Once your trees start to bud out, you need to change your strategy. The winter moth larva hatch and start to crawl to buds to begin their feeding. They are voracious, so you need to pin their ears back by applying some generous sprayings of an organic insecticide called b.t. kurstaki. A quart of it will cost you about $15 to $20, and that’s enough to apply about 20 sprayings to your trees and blueberry bushes. You’ll want to spray about every 3-4 days from around mid April to mid May.

B.t. does a number on the moth larva’s digestive system. It will kill them in large numbers if you are diligent and thorough with your spray applications. This is your best and last option for spray controlling them — once they begin to mature the b.t. is ineffective.

Phase 3 — The poultry option

Nature always seems to provide remedies to balance things out, and in the case of winter moths there is a bonafide natural solution. It’s backyard chickens. They eat just about every bug you can imagine, including some species that pose serious health problems to humans such as deer ticks that carry Lyme disease. Chickens will plow through a big population of winter moths and will utterly devastate it, as long as they have access to the ground underneath the tree or bush.

Chickens are a natural, low-cost and low-impact solution to many bug problems that we currently use expensive and environmentally-damaging pesticides to deal with.  Some communities have progressive laws regarding backyard chickens that allow homeowners the flexibility to own small flocks. Unfortunately, my hometown of Amesbury isn’t one of them. Most people here are prohibited from having chickens due to the size of their lots. And even those who have large enough lots must adhere to onerous regulations. These laws can be changed, but for now, most Amesbury residents need to spray and pray in order to knock back the winter moths.

John Macone operates Farmer John’s Organic Foods, a neighborhood organic farm in Amesbury. Add https://www.facebook.com/Farmerjohnsfoods/ to your list of Facebook likes to keep up to date on fruits, vegetables, plants and fresh eggs that are sold at the farm.


Winter is coming… and so are the moths

It’s mid November and we’ve had enough hard frosts to pretty much kill off nearly every insect, but there’s one remaining pest that’s about to hit us with its full fury. Now’s the time to take some steps to protect your trees and shrubs from this ravaging creature.

It’s the winter moth, an invasive species imported from Europe that can cause devastating damage to your plants. They first arrived in Nova Scotia over a half century ago and slowly migrated southward. They have hit much of New England hard, doing immense damage. They are particularly fond of trees that produce fruited blossoms, like apples, crabapples, pears, cherries, plums, and especially blueberry bushes. They also attack ash and maple trees — sometimes completely defoliating them — as well as other species of native trees.

Around the end of November they will emerge from the ground. The males – ugly grey moths, about 2 inches across – will flock in great droves to lights at night. That’s the signal that the entire population is active and reproducing. The females can’t fly; Instead  they climb up trees and lay their eggs by the tens of thousands.

Next spring — around April — the eggs will hatch, and the small green worms will burrow their way into fruit blossoms and destroy them. They will then move on to the leaves, and in many cases they will strip them bare. If you have winter moth larvae in your trees, you’ll no doubt have seen their “ballooning” migration — they attach themselves to thin, silk-like strands and billow down from trees by the hundreds. After about 6 weeks of heavy feeding, they burrow into the ground, waiting for the winter to arrive to start the process all over again.

The numbers are unbelievable. Scientists say up to 250,000 winter moth larva can hatch in a single tree. Sounds like a locust plague, and in some ways it is. They don’t have any native predators to speak of, so their numbers grow substantially each year as they spread to new territory. In my own experience, they hit our neighborhood like a freight train 2 years ago. They ate their way through many of our neighborhood trees. I have 5 large blueberry bushes that produced 40 quarts each year — until the winter moths arrived.  I haven’t gotten a single berry since then.

What to do

With numbers like this, it’s hard to put a big dent in their population. But you can protect your most cherished trees, such as flowering crabapples or fruit trees. Right now your goal is to stop the females from climbing up the trunk. There’s a few ways to do this.

One way is to get some sticky tree wrap. It’s available in many garden centers. It’s a paper wrap that goes around the trunk, with a sticky coating on the outside that creates a barrier that the moths get stuck on. It’s semi effective — you really need to monitor it, as it can get overwhelmed by the sheer number of climbing moths. They can also crawl underneath it if the bark surface is fairly bumpy — or they will lay their eggs further down the trunk. If you use sticky tree wrap, check on it daily and replace the band as needed.

You can also spray heavy-duty insecticides on the female moths while they are climbing. I’m not a big fan of this approach, as I like to stick with organic solutions. It also requires frequent spraying, and no doubt many moths will muscle through when you aren’t monitoring and spraying. It’s not an effective remedy.

I have a third solution that’s proven highly effective — get some chickens and let them do the dirty work for you. Chickens are a fantastic alternative to pesticides in general. They spend their entire day eating bugs. It’s what they are hardwired to do. Here’s an example — I have a flower crabtree in my yard that was devastated by winter moths. Two years ago they stripped it bare of all its flowers and most of its leaves. The next year I built a chicken run under it,  and the following spring the tree was full of flowers and leaves — and also quite robust from the other “gifts” the chickens laid at its roots.

This year I’ve extended a temporary chicken run around my blueberry bushes. The chickens are already busy digging around underneath them, no doubt finding a trove of winter moths. I look forward to seeing what kind of impact they have on the winter moth population.

In many towns in the local area, raising chickens in your yard is legal and the regulations are common sense. Unfortunately in the town I live in, the rules arechix far too restrictive — it’s too bad, as chickens can solve some of the environmental woes that our government officials spend tons of time and money trying to regulate. But that’s a topic for another day.

This time of year provides you with your first opportunity to fight against the winter moths. If you have them, you should take steps to knock back the adult population by preventing the females from getting up into your most prized trees. In the spring you can wage another campaign against their larva. We’ll talk about that in a few months.

John Macone operates a small organic farm in Amesbury, Mass.