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Looper Activity

Over the past 5 years, several areas on the Sacramento Mountains have experienced defoliation by geometrid moths, also known as loopers. Defoliation from these recent outbreaks was first observed during the 2002 aerial surveys in the Rio Peñasco and Wills canyons east of the Sunspot observatory. Continued defoliation has been observed each subsequent year. Abundant food and favorable conditions have allowed the looper populations to increase quickly. The map below shows the location of the outbreaks (displayed in yellow) on the Sacramento Ranger District of the Lincoln National Forest.



These insects are commonly known as "loopers" or "inch worms" because of how they move. Caterpillars of two different species of geometrid moth have been involved in this outbreak. The first caterpillar identified in 2002-2005 was the New Mexico fir looper. This insect is only known from New Mexico. The adult is a gray/brown moth. Previous outbreaks occurred in 1924, 1928, 1951, 1958 (Furniss and Carolin 2002). The other species involved is Nepytia janetae. This insect has no common name, but is similar to the New Mexico fir looper, being in the same family, Geometridae.

New Mexico fir looper

Nepytia janetae "looping"

Looper defoliation in Scott Able Canyon

Defoliated trees


Larvae (left) and pupae (right) of Neptyia janetae looper



Furniss, R.L. and V.M. Carolin. 1977. Western forest insects. USDA Forest Service. Miscellaneous Publication No. 1339. 654 pp.