cankerworm

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cankerworm,

name for two destructive inchwormsinchworm,
name for the larvae of moths of the family Geometridae, a large, cosmopolitan group with over 1,200 species indigenous to North America. Also called measuring worms, spanworms, and loopers, inchworms lack appendages in the middle portion of their body, causing them to
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, or larvae of geometrid moths. The spring cankerworm (Paleacrita vernata) and the fall cankerworm (Alsophila pometaria) are named for the seasons at which the adults emerge from underground pupation. The spring cankerworm larva overwinters as a pupa, the fall cankerworm as an egg. The larvae, dark green to brown and about 1 in. (2.5 cm) long, feed on the leaves of orchard and shade trees. The spring cankerworm has two pairs of posterior appendages (prolegs); the fall cankerworm has three. The wingless female lays her eggs on the bark, and one control method is the placing of bands of sticky paper around the tree trunks to trap the females before laying. When alarmed, cankerworms drop and hang suspended in midair at the end of a long silken thread secreted from their mouths; they ascend this thread after the danger has passed. The English sparrow was originally introduced in the United States to combat the spring cankerworm. Cankerworms are classified in the phylum ArthropodaArthropoda
[Gr.,=jointed feet], largest and most diverse animal phylum. The arthropods include crustaceans, insects, centipedes, millipedes, spiders, scorpions, and the extinct trilobites.
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, class Insecta, order Lepidoptera, family Geometridae. For control methods see bulletins of the U.S. Dept. of Agriculture.
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cankerworm

[′kaŋ·kər‚wərm]
(invertebrate zoology)
Any of several lepidopteran insect larvae in the family Geometridae which cause severe plant damage by feeding on buds and foliage.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Fall cankerworm (Alsophila pometaria Han., Lepidoptera: Geometridae) is a univoltine pest species native to North America (Porter and Alden 1924).
The timing of late instar cankerworm dispersal is heavily dependent on box elder infestation levels, which varied considerably from tree to tree.
The experiment was started on 19 April 1996, before cankerworm egg hatch began.
A second experiment was performed to determine how cankerworm attack on cottonwood decreases as a function of distance from "source" box elders.
To document the host preferences of fall cankerworm, we performed observational and experimental tests of cankerworm preference.
Increased cankerworm densities translated into higher defoliation levels for cottonwoods associated with box elder.
Potted cottonwoods placed under box elder had almost three times greater cankerworm densities than trees placed under mature cottonwoods, and two times greater cankerworm densities than trees located in the open (treatment F = 15.445; df = 2, 36; P [less than] 0.001; Fig.
When potted cottonwoods were experimentally placed varying distances from box elder trees, we found that cankerworm numbers significantly declined with increasing distance from source box elders, showing that increased distance from box elder resulted in decreased susceptibility to fall cankerworm (Page's [L.sub.a] 309, P [less than] 0.001; Fig.
Clearly, associational susceptibility to fall cankerworm occurs when cottonwoods grow in the immediate vicinity of box elder.
Observationally, cankerworm egg densities were 26 times greater on box elder than cottonwood (U = 8, n = 39, P [less than] 0.001; Fig.
However, 20 of 30 larvae consumed at least some cottonwood, indicating that even though cottonwood is not preferred, it is a potential host for fall cankerworm.
Both experimental and observational results support the conclusion that cottonwood suffers associational susceptibility to fall cankerworm when growing under box elder.