June is proving to be a busy month for new pest reports. Beech leaf disease, which has been spreading from the midwest since 2012, was confirmed in Derry this month. Additionally we received reports of hammerhead worms in Henniker and Kensington. While not a forest pest, it's important to be aware of this worm as it's toxic and should be handled with care. We are also once again seeing very heavy defoliation from spongy moth in areas where we saw it last year. To date we have mapped over 32,000 acres of defoliation in Carroll County. The good news is we are starting to see caterpillars dying from diseases (nucleopolyhedrosis virus (NPV) &Entomophaga maimaiga fungi) which typically cause outbreaks to collapse. Aerial surveys are underway to delineate the extent of forest damage from this and other agents throughout the state. Read on for more info on these and other important forest pests in NH.
You can find more info and submit reports at nhbugs.org
Graphic: Ontario's Invading Species Awareness Program
Pest Spotlight - Beech Leaf Disease
Beech leaf disease (BLD), which first appeared in Ohio in 2012, and Maine and Massachusetts last year, was confirmed in leaf samples this month from a European beech in Derry. BLD is a foliar disease of American beech, European beech and Oriental beech caused by the Asian nematode Litylenchus crenatae and potentially by several bacteria’s and fungi the nematode transmits. Nematode feeding can begin at bud break causing dark banding between the veins of tender foliage. As the season progresses and damage worsens the leaves become leathery in texture and dark banding can turn yellow and kill affected branch tips. Tree mortality can occur within a few years and there are currently no treatment options available for this disease.
Spotted Lanternfly has not been detected in NH yet but has been intercepted in nursery stock. You can help us keep an eye out for it, especially if you recently purchased landscape trees or traveled from an infested area. They are particularly fond of tree of heaven so if you have these in your area you can monitor them for early signs of an infestation. Report any sightings in NH to nhbugs.org.
Jumping Worms have been reported in every county in the state. Adults are easiest to ID July-October. We are currently conducting a survey and looking for sites to visit to determine the impact on NH's forests. You can help by filling out our survey below.
Since the past newsletter, emerald ash borer was detected in two additional towns during the completion of our annual winter survey. These towns are Orford and Thornton and represent the continued spread of the ash borer northward and westward. In past years, the New Hampshire Forest Health Program would deploy purple prism traps that many people may be familiar with across the state. These traps served as one of our primary detection methods for finding infestations in new locations, but as the affected area is now nearly the entire state with the exception of Coos County and far northern Grafton and Carroll Counties, we have foregone the deployment of these traps. Visual surveillance of the North Country will still be carried out to locating the ash borer as it moves the region.
We continue to utilize biological control as a means to attempt to manage emerald ash borer into the future and will be releasing natural enemies at locations in Rindge, Croydon and Wakefield. We are also continue to monitor the establishment and spread of the parasitic wasps released through the biocontrol program at our past release sites with encouraging results. Wasps were recovered from five of the eight sites that we evaluated, some of which were up to five miles from the nearest release location. This past winter we stored EAB-infested logs from eight additional locations throughout the state in barrels to monitor for the presence of the parasitic wasps and expect results to be in later in the summer.
We are also in the third year of a multi-year project where we aim to protect clusters of healthy, forested ash trees with insecticide at 100 locations throughout the state. Sixty sites were treated in the first two years of the project and we are currently seeking additional sites. An appropriate site should have at least a few dozen healthy, mature ash trees located in a natural forested setting. If you or anyone you know have a suitable site and would be willing to participate in the program please contact Bill Davidson at William.davidson@dncr.nh.gov.
Ash is a masting species, meaning across wide regions they only produce seeds every few years, and 2022 is turning out to be the first big ash seed year since 2018. This mast year came at a great time as it will likely be the last for many of the mature ash trees across the region before they succumb to the emerald ash borer. This year’s large influx of ash seeds to New Hampshire’s forests should serve to propagate a bountiful generation of seedlings which can begin the process of filling the gaps created by their dead and dying parent trees. In an optimistic future where the biological control program is successful, some of these trees may live to incorporate into the forest and reach maturity themselves.
Ash produce clusters of seeds coated with a papery wing known as a samara. Trees across the state can be seen producing large amounts of these seeds this year. (Photo: Bill Davidson)
