INSECTS THAT FEED ON COLORADO TREES AND SHRUBS1 Whitney Cranshaw David Leatherman Boris Kondratieff Bulletin 506A TABLE OF CONTENTS DEFOLIATORS .................................................... 8 Leaf Feeding Caterpillars .............................................. 8 Cecropia Moth ................................................ 8 Polyphemus Moth ............................................. 9 Nevada Buck Moth ............................................. 9 Pandora Moth ............................................... 10 Io Moth .................................................... 10 Fall Webworm ............................................... 11 Tiger Moth ................................................. 12 American Dagger Moth ......................................... 13 Redhumped Caterpillar ......................................... 13 Achemon Sphinx ............................................. 14 Table 1. Common sphinx moths of Colorado .......................... 14 Douglas-fir Tussock Moth ....................................... 15 1. Whitney Cranshaw, Colorado State University Cooperative Extension etnomologist and associate professor, entomology; David Leatherman, entomologist, Colorado State Forest Service; Boris Kondratieff, associate professor, entomology. 8/93. ©Colorado State University Cooperative Extension. 1994. For more information, contact your county Cooperative Extension office. Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, Milan Rewerts, interim director of Cooperative Extension, Colorado State University, Fort Collins, Colorado. Cooperative Extension programs are available to all without discrimination. No endorsement of products named is intended nor is criticism implied of products not mentioned. Insects That Feed on Colorado Trees and Shrubs Page 2 Western Spruce Budworm ....................................... 16 Pine Budworm ............................................... 17 Large Aspen Tortrix ........................................... 18 Cankerworms and other Loopers .................................. 18 Table 2. A summary of the life history of common inchworms (Family: Geometridae) developing on trees and shrubs in Colorado ............ 19 Uglynest Caterpillar ........................................... 19 Fruittree Leafroller ............................................ 19 Juniper Webworm ............................................ 20 Forest Tent Caterpillar ......................................... 21 Sonoran Tent Caterpillar ........................................ 21 Western Tent Caterpillar ........................................ 22 Table 3. Tent-making caterpillars and sawflies of Colorado ................ 22 Snailcase Bagworm ........................................... 23 Spiny Elm Caterpillar/Mourning Cloak .............................. 24 Hackberry Butterfly ........................................... 24 Pine Butterfly ............................................... 25 Leaf Feeding Beetles ................................................ 25 Rabbitbrush Beetle ............................................ 26 Cottonwood Leaf Beetle ........................................ 26 Elm Leaf Beetle .............................................. 27 Flea Beetles ................................................. 28 Ashgray Blister Beetle ......................................... 29 Black Vine Weevil ............................................ 29 Severity of Defoliation injuries ................................... 30 Leaf Feeding Sawflies ............................................... 32 Pearslug (Pear sawfly) ......................................... 32 Imported Currantworm ......................................... 33 Brownheaded Ash Sawfly ....................................... 33 Poplar Leaffolding Sawfly ....................................... 34 Conifer Sawflies .............................................. 34 Bull Pine Sawfly ............................................. 35 Juniper Sawfly ............................................... 36 Web-spinning Sawflies ......................................... 36 Table 4. Sawflies recorded from Colorado that feed on trees and shrubs7 ....... 30 Leafcutter Bees .............................................. 39 Grasshoppers ................................................ 39 LEAF AND NEEDLEMINERS ........................................ 41 Aspen Leafminer ............................................. 41 Spotted Tentiform Leafminer ..................................... 42 Lilac Leafminer .............................................. 42 Insects That Feed on Colorado Trees and Shrubs Page 3 Ponderosa Pine Needle Miner .................................... 43 Pinyon Needleminer ........................................... 43 Pine Needle Sheath Miner ....................................... 44 Spruce Needleminer ........................................... 44 White Fir Needleminer ......................................... 45 Poplar Blackmine Beetle ........................................ 45 Elm Leafminer ............................................... 46 Birch Leafminer .............................................. 46 Table 5. A Key to Common Insect Groups causing Foliage Injuries to Woody Plant Foliage ........................................... 47 GALL MAKERS .................................................. 48 Cooley Spruce Gall Adelgid ..................................... 48 Petiolegall Aphids ............................................ 50 Poplar Vagabond Aphid ........................................ 51 Hackberry Nipplegall Maker ..................................... 51 Hackberry Budgall Psyllid ....................................... 52 Eriophyid Mites .............................................. 53 Table 6. Common deformities to woody plants caused by eriophyid mites in Colorado ........................................ 54 Poplar Budgall Mite ........................................... 55 Ash Flowergall Mite ........................................... 55 Pinyon Spindlegall Midge ....................................... 55 Pinyon Stunt Needlegall Midge ................................... 57 Stubby Needlegall Midge ....................................... 57 Gouty Veingall Midge ......................................... 58 Honeylocust Podgall Midge ...................................... 58 Willow Cone Gall Midge ....................................... 59 Juniper Tip Midge ............................................ 59 Poplar Twiggall Fly ........................................... 60 Rabbitbrush Gall Makers ........................................ 61 Rose Gall Wasps ............................................. 62 Gall Wasps Associated With Oak .................................. 62 Rough Bulletgall Wasp ......................................... 63 Willow Gall Sawflies .......................................... 64 Willow Redgall Sawfly ......................................... 64 TIP MOTHS, TWIG AND TERMINAL BORERS ........................... 66 Southwestern Pine Tip Moth ..................................... 66 Pinyon Pitch Nodule Moth ...................................... 67 Cottonwood Twig Borer ........................................ 67 Peach Twig Borer ............................................ 68 Insects That Feed on Colorado Trees and Shrubs Page 4 Pinyon Tip Moth ............................................. 69 White Pine Weevil ............................................ 69 Gouty Pitch Midge ............................................ 71 Pemphredon Wasps ........................................... 71 Rose Stem-Boring Sawfly ....................................... 72 BARK AND TWIG BEETLES ........................................ 74 Twig Beetles ................................................ 74 Western Cedar Bark Beetles ..................................... 75 Mountain Pine Beetle .......................................... 75 Douglas-fir Beetle ............................................ 77 Red Turpentine Beetle ......................................... 78 Engraver Beetles ............................................. 78 Ash Bark Beetles ............................................. 79 Shothole Borer ............................................... 79 Smaller European Elm Bark Beetle ................................. 80 BORERS OF TRUNKS AND LARGER BRANCHES ........................ 82 Pinyon "Pitch Mass" Borer ...................................... 82 Table 7. Flight Periods and Hosts of Common Woody Plant Borers in Colorado ..................................................... 83 Zimmerman Pine Moth ......................................... 84 Carpenterworm .............................................. 85 Peach Tree Borer ............................................. 86 Table 8. Common Colorado Clearwing Borers (Sesiidae) Captured by Pheromone Traps ........................................ 86 Currant Borer ................................................ 87 Lilac/Ash Borer .............................................. 88 Raspberry Crown Borer ......................................... 89 Elder Shoot Borer ............................................ 90 Cottonwood Borer ............................................ 90 Locust Borer ................................................ 91 Pole Borer .................................................. 91 Blackhorned Pine Borer ........................................ 92 Ponderous Borer