Insects Associated with Maine Cranberries:

Pest Profiles — Insects found on Maine commercial cranberry beds (those found most often and most consistently from year to year):

How do they spend the winter?

  • Egg stage: Blackheaded fireworm | Bluntnosed leafhopper | Cranberry blossomworm | Redheaded flea beetle | Spongy moth | Green spanworm
  • Larval stage: Cranberry fruitworm, as a larva, but inside a protective structure called a hibernaculum
  • Pupal stage: Brown spanworm | Big spanworm | Cranberry tipworm
  • Adult stage: Cranberry weevil (beetle stage) | False armyworm (moth stage) | Winter moth (moth stage) | Yellowheaded fireworm (moth stage)

Emerging Insect Pests and/or pests less commonly encountered on Maine commercial cranberry beds:

  • Scale Insects (Putnam, Latania, Dearness): No scale insects have been observed yet on any cranberry vines in Maine (we can count ourselves very lucky if that remains true)! They are now a serious problem at a large number of Massachusetts cranberry sites. You can learn more about them, and find some excellent photos of the scale insects (and bog symptoms) that Massachusetts growers are seeing, by visiting the UMass Cranberry Experiment Station’s web site.
  • Winter Moth: Potentially a problem for Maine cranberries in the future, but it has not yet been reported or confirmed on any Maine cranberry beds; winter moth is a new and invasive spanworm pest that has caused problems in Massachusetts; it is always possible it could show up at a Maine cranberry site someday, but the females do not have wings so they cannot spread very quickly on their own.
  • Humped Green Fruitworm: Amphipyra pyramidoides (Guenée) [relatively rare but a few of these larvae are usually encountered each year at perhaps 5% of the locations that are monitored statewide, but never–thus far–at threshold levels except when added to False Armyworm counts]
  • Blunt-nosed Leafhopper: Limotettix (=Scleroracus) vaccinii (Van Duzee) [this insect is a vector for False Blossom disease] Not seen in Maine’s modern cranberry era until the 2009 growing season, when it was found at two separate locations, with a large outbreak at one of those locations.  Another location saw high numbers of them in 2015 and 2016, and they were found fairly routinely on many Maine cranberry beds in 2017 and 2018.
  • Sparganothis Fruitworm: Sparganothis sulfureana (Clemens) [Larvae are rarely detected anymore in commercial Maine cranberry beds, even at organic sites, but moths are captured easily and consistently from year to year whenever pheromone traps are used, though generally not in very high numbers; trap counts are often so low that it is difficult to judge when the peak flight has taken place]
  • Cranberry Girdler: Chrysoteuchia topiaria (Zeller) [larvae have not been found as yet on any Maine cranberry beds whenever searches have been conducted, but the moths are seen commonly]
  • Sawfly larvae: (Action threshold is 30 to 40 per 25 sweeps) (Found in Maine most often in June) Sawfly larvae have not ever been found at threshold yet in any Maine commercial cranberry bed, though it was close once in 1999 at one location in eastern Washington County. Note: The adult sawfly is a small, solitary, non-stinging wasp.

See also: