The entire state of Massachusetts is quarantined for Emerald Ash Borer (EAB) in an effort to stop its spread, pursuant to USDA-APHIS Federal Regulation -7 CFR, 301.53. The full state quarantine regulation took effect on Feb. 9, 2015.
“Emerald ash borer has spread quickly across the United States since its first documented find in the Detroit, MI area in 2002 and is now found in 30 states. The insect’s rapid spread is primarily due to people moving ash wood products. This can be as firewood or by people in the green industry who move wood products as part of their occupation,” said Ken Gooch, of the Massachusetts Department of Conservation and Recreation (DCR) who spoke at the Invasive Insect Certification Program for Landscape, Nursery, and Urban Forest Pests provided by UMass Extension late February. “EAB’s natural spread is half to one mile a year; people do the rest.”
The USDA APHIS and Massachusetts Department of Conservation and Recreation Forest Health Program work together as part of the Cooperative Emerald Ash Borer Project. EAB was initially confirmed to be in Massachusetts on August 2012, found on a purple panel trap in the Berkshire County town of Dalton and has since been located in other counties across the state including Essex, Suffolk, Worcester and Hampden. “Seems like every year we find EAB in a new community.” Therefore, it makes sense “if you are moving wood, keep it local,” said Gooch.
Unlike another invasive insect affecting trees in Massachusetts, the Asian longhorned beetle (ALB), which has shown affected trees can live infested for eight to 10 years or more, EAB can kill a healthy ash tree in two to three years.
“Our job is to monitor the spread of EAB,” said Gooch, plus establish other insect biological controls. In 2016, they girdled 38 trees, and set out 14 green funnel traps and 31 purple panel traps as part of their monitoring. In 2017 they will be working with the green funnel traps provided by the USDA APHIS, steering away from purple panel traps due to lack of funding. Traps and girdled ash trees are strategically placed across the state in areas known to have EAB to track the spread of the invasive insect. They girdle ash trees in the spring and return in the fall to peel back the bark to see where the infestations are.
Recently an EAB infestation was confirmed close to the Connecticut River in the town of Longmeadow. This EAB infestation is very light and is not yet at the level where it makes sense to release biological control insects, he said.
Another method to monitor for the presence of EAB is called biosurveillance. The DCR along with the Massachusetts Department of Agriculture and the USDA APHIS monitor for a native, ground nesting wasp called Cerceris fumipennis, which emerges around July 4 each year. “It’s a very cool insect,” said Gooch. A predatory wasp, it is non-stinging but unfortunately “everybody goes out and tries to kill it.” It builds its nests in hard-packed sandy areas including baseball and sometimes soccer fields. “It brings back not only EAB, but other insects in the Buprestid beetle family as well to feed its young.”
Since 2013, the DCR has released 1,304 adult and 3,338 larval EAB parasitoids called Tetrastichus planipennisi; tiny, non-stinging parasitic wasps which are raised at a USDA insect rearing lab in Detroit, MI. The parasitic insects are shipped in the larval stage inside wooden bolts which are nailed onto infested trees. This wasp lays its eggs into EAB larvae. The wasp larvae then eats EAB from the inside out. The DCR has also released 4,050 Oobius agrili larvae which are an EAB egg parasitoid. A third parasitoid, Spathius galinae, previously released in New York, is being considered for possible release in Massachusetts this year by the DCR.
Some of the biocontrol insects the DCR is working with for Hemlock Woolly Adelgid (HWA) include Laricobius nigrinus, Pseudoscymnus tsugae, and Laricobius osakensis. Unfortunately, there are issues in getting the biocontrols established. “Not having much luck in recovering the Laricobius nigrinus insect on Mt. Tom,” said Gooch. Issues could be compatibility with weather conditions: one Laricobius strain was from out west and another raised in a lab at Virginia Tech.
“There is federal funding and state funding available to do pesticide treatments. One of our major problems is elongate hemlock scale (EHS),” said Gooch. Dinotefuran is a pesticide applied directly to the hemlock tree trunk at the base of the tree and is absorbed through the bark. The DCR Forest Health Program has plans to treat hemlocks affected with hemlock woolly adelgid and elongate hemlock scale this spring, using dinotefuran which manages both insects, at Mt. Tom State Reservation as well as other DCR properties across the state.
The Southern Pine Beetle (SPB) was recently found for the first time in Massachusetts during 2015. The insect leaves visible resin marks or pitch tubes on tree trunks during heavy insect feeding. It is a very aggressive insect and, when established within pine stands, can cause rapid tree mortality causing concern in our state for areas with large populations of pitch pine. “We will be doing trapping again this year.” The insect was documented to be killing pitch pines on Long Island, NY in 2014 which led the U.S. Forest Service to ask their cooperating states throughout New England to trap for SPB in 2015. There is the fear of it getting established [in Massachusetts] as our climate is getting warmer.” It took multiple SPB generations per year for it to be established in Long Island.
“Currently in Massachusetts, the SPB has one to two generations per year but as it gets warmer, causing multiple generations, the trees can’t fight it off,” said Gooch.
The DCR Forest Health Program also catalogs past big insect outbreaks, including non-natives like browntail moth and pear thrips. Pear thrips affected sugar maples in the Connecticut River Valley in the late 1980’s-early 1990’s then went away. Pear thrips could again be an issue if the right conditions exist for the insect to thrive. Other past native insect outbreaks seen in Massachusetts include Nantucket pine tip moth, forest tent caterpillar, eastern hemlock looper — an insect which makes V-shaped notches in hemlock needles — and cherry scallop shell moth which defoliates cherry trees.
“Insects are smart,” he said. In forested settings “they are dispersing a lot wider than they would in an urban area.” Vigilance is key.