Less
Defoliation Of Trees Expected This Year
The Rhode Island Department of Environmental
Management (DEM) is advising homeowners that it does not anticipate widespread
defoliation of trees by gypsy moth caterpillars in Rhode Island this year, as
occurred in 2016 and 2017. There will still be some localized areas, however, where tree defoliation may be severe.
Surveys conducted last fall by DEM's Division of Forest
Environment showed a marked decline in the number and size of gypsy moth egg
masses in the environment; thus, there will be fewer caterpillars hatching this
spring.
Areas expected to be hit hardest include central Providence County and Washington County, although all forested lands, parks, and urban green spaces are still somewhat at risk.
Areas expected to be hit hardest include central Providence County and Washington County, although all forested lands, parks, and urban green spaces are still somewhat at risk.
Spring rains last year promoted the emergence and spread of the Entomophaga maimaiga fungus, a pathogen deadly to gypsy moth. This resulted in significant caterpillar mortality.
Spring rains this year will once again release Entomophaga, likely causing a total collapse of the caterpillar population. Unfortunately, some trees will be defoliated before this happens. A report on the status of the current outbreak can be found by clicking here.
Homeowners may opt to apply insecticides to control caterpillars
on their property, minimizing damage to their trees. Products containing the
active ingredient "Btk" are recommended and widely available at
retail outlets.
Many tree care specialists are licensed in pesticide application, and may be contracted to do so. Click here for information on contracting with a tree care specialist providing this service. DEM does not advocate for the widespread use of pesticides in forested areas because they also harm beneficial insects, such as bees and butterflies, and has no plans to apply pesticides this year.
Many tree care specialists are licensed in pesticide application, and may be contracted to do so. Click here for information on contracting with a tree care specialist providing this service. DEM does not advocate for the widespread use of pesticides in forested areas because they also harm beneficial insects, such as bees and butterflies, and has no plans to apply pesticides this year.
For more tips on caring for trees, visit www.dem.ri.gov. Follow
DEM on Twitter (@RhodeIslandDEM) or Facebook at www.facebook.com/RhodeIslandDEM
for timely updates.
Did You Know that the gypsy moth is an invasive species and most
of the gypsy moths in North America came from Europe?
It was accidentally introduced in the late 1860s in Medford, MA. One of the most devastating forest pests in the Northeast, the gypsy moth is continuing to spread its range.
It was accidentally introduced in the late 1860s in Medford, MA. One of the most devastating forest pests in the Northeast, the gypsy moth is continuing to spread its range.
Beginning in mid-late April and continuing through late June,
the caterpillars will consume leaves of many species of broadleaf trees and
shrubs – such as oaks, aspen, apple, speckled alder, basswood, gray and river
birch, and willow.
Less desired but still attacked are maple, black, yellow, and paper birch, cherry, cottonwood, elm, black gum, hickory, hornbeam, larch and sassafras. Older gypsy moth larvae devour foliage of several species that younger larvae normally avoid, such as hemlock, and pines and spruces native to the East.
Less desired but still attacked are maple, black, yellow, and paper birch, cherry, cottonwood, elm, black gum, hickory, hornbeam, larch and sassafras. Older gypsy moth larvae devour foliage of several species that younger larvae normally avoid, such as hemlock, and pines and spruces native to the East.
"Despite over 100 years of presence in North America,
researchers are still at a loss to explain and predict the extent of the
changes in forest vegetation likely to take place through gypsy moth
disturbance," according to the U.S. Forest Service.
"A major concern is the potential loss of economically critical and ecologically dominant oak species (Quercus, spp.). Most studies of forest compositional changes with gypsy moth defoliation indicate that less susceptible species will dominate the forest, so in effect, forests may have fewer gypsy moth problems in the future."
"A major concern is the potential loss of economically critical and ecologically dominant oak species (Quercus, spp.). Most studies of forest compositional changes with gypsy moth defoliation indicate that less susceptible species will dominate the forest, so in effect, forests may have fewer gypsy moth problems in the future."
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