Wildlife & Nature

Gypsy Moth Caterpillars Take Rhode Island By Surprise


Gypsy moths are back, and, according to Rhode Island officials, it’s a full-fledged outbreak not seen since the early 1980s.

“We don’t know where it came from. We were totally taken by surprise by the extent of the infestation,” said Paul Ricard, forest health program coordination for the state Department of Environmental Management (DEM).

Worst hit are oak and other hardwood trees in rural regions such as North Smithfield, Smithfield, Coventry, Glocester, Cumberland and West Greenwich. Urban areas, so far, have been spared.

The outbreak is most troubling because it comes just as trees were recovering from the damage inflicted by the winter moth, which defoliated hardwood trees across the state. The gypsy moth caterpillar started appearing around Memorial Day weekend, the exact time the winter moth finished making Swiss cheese out of deciduous tree leaves.

The number of gypsy moths was small at first, Ricard said, showing up in small pockets as they do most years. During the Past week, however, the gypsy moth caterpillar population exploded statewide and is hitting trees with another round of intense leaf-eating.

To make matters worse, there is nothing the state or tree owners can do to halt the damage. Had there been advanced warning, the state could have sent out public warnings and broadcast preventative tips, such as adding barrier capes around tree trunks.

Most of the damage is already done, as the moths are nearing the pupal stage, which begins in July. For preventative steps to work, they need to begin in the fall.

Ricard advises the public not to cut down trees that look like they have little or no leaves remaining.

“Healthy trees can survive years of defoliation,” he said. “Trees are very resilient. They have been around a long time.”

Drought, however, can be a death knell for a defoliated tree. Richard suggests watering damaged trees if they go a week or more without an inch of rain.

It can’t hurt to pull the caterpillars off trees, as well, he said. Caterpillars feed at night when they are less visible to predators, and can be seen climbing tree trunks in the evening.

It’s too late for aerial spraying, but it’s not to early to plan for next year when the gypsy moth may return, Ricard said.

“If there is ever going to be (spraying), it’s going to take political backing and it will help to take action between now and next spring,” he said.

Unlike the spraying done in the 1980s, the spray used today is less toxic. Bacillus thuringiensis kurstaki (Btk) is a naturally occurring bacteria that kills moths, and causes nothing more than eye irritation in humans.

The black caterpillars don’t bite but some people develop a rash from their hair that can last four to five days. The caterpillars’ tiny black droppings also create a sticky nuisance for lawn furniture and parked cars.

It’s not easy to know if the gypsy moth will return next year, but they can survive in extremely cold weather and snow.

For now, Ricard is answering the nonstop stream of phone calls from a worried public. “It’s taken everyone by surprise,” he said.


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  1. This is the damage the Caterpillar’s have done to this Oak tree


  2. They damaged my trees in Smithfield but I would rather have the damage than any spray even if it is "less toxic". We can’t afford to keep spraying chemicals into the environment. Many other life forms are affected by the poison…including humans.

  3. I’ve noticed an number seem to be succumbing to the pathogen that makes them "v" in death and some look very quiet! Perhaps there is hope they will self destruct.

  4. We do not need to spray, There are hanging traps, they can be trapped and may not be as wide spread effective but the spray will affect all other moths and therefor the food chain. Do not support spraying. These catapillers suddenly become huge (approx 4inches) I look up in my trees and there are bundles of them together. Makes me want to spray with bee spray or ant spray. Something that can aim and just kill the section I am pointing at vs my whole yard or city. Whatever happened to the white netting type nests? They use to be obvious to spot, and now they aren’t. Yuck

  5. Apparently, caterpillars cannot swim. I have several dead ones that did not survive the 2 heavy rainfalls we had recently.

  6. Currently I have started to physically remove the eggs which are the yellow patches all over the trees, on rock walls, under everything, however as I look up into the trees surrounding my yard in town, I can see thousands of the yellow patches, they are everywhere, in the maple trees here in Wakefield. This year was really bad, but I imagine that when these eggs hatch next year we will be in a full out invasion. There is no way I can remove a fraction of them. MLR

  7. The unusually dry spring reduced the activity of the virus and fungus that usually kill the caterpillars. Same thing happens with Japanese Beetles. If there is a lot of rain when they emerge, not as many survive.

  8. It’s June 1, 2016… There are more caterpillars now than I remember from the mid 80’s when there were no leaves on the trees by July…

  9. Actually. I read last summer they were in surprisingly large volume and that an outbreak was possible this year. They are known to be in outbreak numbers for up to four years according to experts.

  10. I have been house bound because of these caterpillars! I can’t even walk my dog around my yard. The grass,trees,patio, driveway are infested. You can literally hear them chomping on the trees. It’s so disgusting. My husband sprayed around the outside of the house, deck, and even the plants and some trees outside. It didn’t seem to make a difference. I hate being forced to stay indoors. It’s either that or take off everyday. I can’t wait till this is over!! Ugh!!
    Western Coventry RI

  11. I have gotten a nasty rash all over my arms and legs,from the caterpillars.Had to go on prednisone.Rash lasted two weeks. I then cut my grass and now have the rash again. Due to all the dead caterpillars in the lawn.I am glad there turning into moths now. Hopefully this is a one year thing.

  12. I have had gypsy moths for the last two years, I hope DEM will not be surprised again next year and do some spraying!!!! Bruce , Smithfield

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