September 3, 2021
Great News! We have been hearing from MPOA members that the Lymantria dispar dispar (LDD – formerly referred to as gypsy moth) invasion has subsided. Members are not seeing the expected egg masses in their trees this month.
In the FOCA (Federation of Ontario Cottagers’ Associations) August ‘Elert’ there is a Newsletter from the Lake Steward. The newsletter contains a comprehensive article on LDD including the map below. We though you might find the map particularly interesting as it shows that we were at the epicentre of the invasion.
This is the link to the Lake Stewards Newsletter. Scroll to page 14 for the LDD article
July 9, 2021
The MPO received this email about gypsy moth traps from Ross Breen, Stone Soup Farms Ltd. of Harlowe, ON
We are all struggling with the Gypsy Moth infestation and pheromone lures for trapping the male moths are in short supply. Petro-Canada Northbrook has them available for $5+taxes. This trapping stage of the battle against this pest is crucial to knock the 2022 population down by preventing males from mating with females and decreasing the number of eggs for next year’s hatch. These lures can be used in store-bought traps or homemade.
These lures are pheromone impregnated rubber bands and were freshly made by scientists. See attached picture – Gypsy Moth Lures.
The lures can be kept at room temperature pretty much all season. If there are spares at the end of the season, then they should be triple bagged and placed in the freezer. They will easily last until next season.
Spacing - 6 traps in 1 acre. But if you have many acres, more like 4 traps for every acre. You don't want the traps too close together, because the air will become saturated with pheromone. If that happens the moths become confused, don't know where to fly to, and tend not to fly into the traps at all, so you don't catch many.
A portion of sales will be donated to The Friends of Bon Echo Park and the Canadian Wildlife Federation.
See attached picture – Yoghurt Container Trap. Trials have shown this style of trap works 10X better than a bottle trap and is easier. If you would like to see instructions for a bottle trap there are several on YouTube including this one https://youtu.be/D02_42GtcU8. You would replace the pheromone shown with the impregnated rubber bands.
June 30, 2021
This post was on the 'What's Happening in Northbrook/Flinton/Kaladar/Cloyne' Facebook page. It's a great summary about gypsy moths and why you should not cut down the compromised trees:
Cultivated Art Inc.
Don’t cut down any of your defoliated trees and shrubs, even the evergreens.
Observations of a forest ecosystem during an extended population boom of foliage feeding caterpillars:
Over the six years we have been spending time with the land and forest a bit west of Perth, there have been 5 years of high population of tree feeding caterpillars. The Forest Tent Caterpillars arrived first, entirely defoliating cherry, oak and big toothed aspen trees and moderately feeding on wild apple, hawthorn and a few other species.
As their population peaked and declined, the LDD (Lymantria dispar dispar / Gipsy Moth) population began their climb. Last year they entirely defoliated the oaks and aspens, and then, to my surprise, moved on to the white pines and pretty much any other plant, including herbaceous perennials and raspberry bushes.
So, what happens to a mostly forest ecosystem with this many years of heavy foliar feeding?
The oak trees have proven to be startlingly resilient, re-leafing lushly every summer. Some, minor, thinning of the interior canopy has occurred, but even the very young trees have held their own overall.
Even the white pines branches that were stripped of foliage retained their growth tips and have started filling back in nicely.
The undergrowth is where I’ve seen the most significant shift. The combination of reduced sun and moisture competition in early summer (trees without leaves cast few shadows and drink little water), with fertilizer literally raining down for a month in the form of caterpillar droppings, made for awfully nice growing conditions.
The oak sedge is incredibly thick and lush and the small patch of wild leeks has the most flowers ever.
The defoliation feels pretty traumatic. It is shocking to see the leaves disappear. Even more so to see evergreens stripped of their previously permanent foliage. But the growth tips and leaf buds remain. Healthy trees can hold out through a few years of caterpillar loading.
Since evergreens generally hold needles for 2 to 5 years before naturally dropping them, they will take about three years to look like their old selves.
The nutrients from those leaves doesn’t leave the ecosystem. It rains down to the soil, where it is captured by the undergrowth, which will, in turn, release much of it back to the trees as the canopies fill back in.
In areas where the cycle has just started, protect your evergreens next year by removing as many of the egg masses as you can find between their laying in a couple of weeks and their hatching next spring. Wrap the trunks in burlap, fold it down and then empty the resulting trap daily for a few weeks next spring.
The up side of having multiple years of high caterpillar population is that the virus that reduces their population (multicapsid nuclear polyhedrosis virus or LdMNPV) is now becoming quite established in the local ecosystem and, despite the thousands of egg masses and the tens of thousands of tiny hatchlings I saw this spring, the damage to the trees is far less than I was expecting this summer.
I’m actually seeing the highest number of caterpillar fatalities on the evergreens that had the most feeding last year. Enough that they have less feeding than the trees that weren’t munched on before, which makes me doubly glad that I didn’t clip off the defoliated branches.
May 23, 2021
Entomologist questions safety, benefits of gypsy moth spraying.
Click the link below for interview with Gard Otis, a Professor Emeritus at Guelph University.
Addington Highlands on the gypsy moth outbreak this spring:
Anyone who has had the time to patrol their property and look for gypsy moth egg masses will know that there are a lot of egg masses out there! The Ministry of Natural Resources and Forestry did some detailed sampling across the infected zone and have forecasted that, should all of these eggs hatch successfully and develop through all of their larval stages, we should expect “severe” defoliation. Use the link below for the full article.
The Ontario Government has an excellent web site on gypsy moth.
Our MPOA Lake Stewart - Vern Haggerty advises that there is useful information on the site. One point of interest he notes is that the Ministry is predicting severe defoliation for our district again this year. He is also hopeful that Mother Nature proves them wrong.
Gypsy moth Pheromone traps
Due to the extensive Gypsy moth outbreak we are currently experiencing, the MPOA will not be offering gypsy moth traps for sale this year. Traps probably reduce the number of fertilized females when moth populations are low between major outbreaks, however they offer virtually no benefit currently.
it may be satisfying to empty a trap full of dead moths every few days during a major outbreak this does nothing to reduce defoliation. The caterpillars do all the munching, only males can fly and females are generally found on or near the trees they fed upon. Due to the number of male moths in flight last year and the expected number this year the use of female pheromone traps would do little to disrupt males from finding and fertilizing the real females.
Aerial spraying of Baccilus thuringiensis Aerial spraying by a company like Zimmer aviation is expensive (about $400 per lot up to one acre) but, if done at the critical time when eggs have just hatched around mid to late May, will definitely reduce defoliation on the sprayed area. Contracts with Zimmer are required no later than March 1, 2021. Some, including experts from the MNRF, argue that spraying may delay the emergence of some natural pests such as those listed below. For this reason and due to the expense of widespread spraying MNRF does not plan to do spraying on crown land near Mazinaw.
Natural enemies of the Gypsy moth This NPV (nucleopolyhedrosis virus) is usually the most important factor in the collapse of gypsy moth outbreaks in North America. The virus is always present in a gypsy moth population and can be transmitted from the female moth to her offspring. It spreads naturally through the gypsy moth population, especially when caterpillars are abundant. During a gypsy moth outbreak, caterpillars become more susceptible to this virus disease because they are stressed from competing with one another for food and space. Typically, 1 to 2 years after an outbreak begins, the NPV disease causes a major die-off of caterpillars.
Another natural killer of gypsy moth caterpillars is a fungus called Entomophaga maimaiga. Fungal spores that overwinter in the soil will infect young caterpillars early in the summer. When the young caterpillars die, their bodies produce windblown spores that can spread and infect older caterpillars. Large caterpillars killed by the fungus will hang head down from the tree trunk, and the bodies of the dead caterpillars appear dry, stiff and brittle. Within several days, the cadavers fall to the soil and disintegrate, releasing the spores that will overwinter back into the soil.
Destroying egg masses The best bet for management of future gypsy moth damage to your property in the short term if you choose not to spray is to remove and destroy egg masses in the late summer. Use a hand-held vacuum or scraper and collect eggs into a bucket that you fill with soapy water for 48 hours to kill them.