Colorado State Forest Service

Insect and Disease Quarterly Report August 2010 Volume 2, Issue 3

Inside this Issue: The Bark Trifecta Feature: The Mountain pine beetle (MPB) little beetle has made large impacts and drought. In this epidemic, Trifecta 1 has been featured in the media on the pine forests of western MPB has impacted almost 3 mil- numerous times over the last sev- North America for more than a lion acres of Colorado’s forests

eral years as the epidemic in Colo- decade. since 1996. Thousand Cankers Disease rado continues. Yet, recently, MPB # 2 Ips Beetle Update 1 has been sharing headlines with Ips are bark beetles that other beetles. But who are all these have been gaining momentum in other beetles? Firewood and the Spread of the wake of MPB. “Ips beetle” is a Bark and Twig Beetles term used to identify Ips pini the Pests 2 Bark and twig beetles have sev- pine engraver. Ips is a dark reddish

eral characteristics in common. brown to black beetle that is 2-6

Spotlight: European Elm • In the same taxonomic family mm in length. Ips beetles also have characteristic spines on their elytra. Flea Weevil 2 • Phloem feeders The face of mountain pine bee- tle, Dendroctonus ponderosae. Relatively small and cylindrical • MPB is a native to Western for- Things to Watch For 4 There are over 100 species of bark beetles native to Colorado, but only ests and is part of Colorado’s forest

about 10 of them are key players in community. MPB usually kills a Events and Announcements 4 the forests. Even fewer make the small number of pine trees ever front page news. year in small clumps on the land- Let’s look at a few of the bark scape. The beetle attacks the main Spines on elytra of ips beetle, Ips bole or trunk of the tree. First kill- and twig beetles getting press for pini. their activities on Colorado’s for- ing trees suffering from another ested landscape. ailment like drought, dwarf mistle- Ips beetle is also native to the toe, a lightning strike or a fire dam- # 1 Mountain Pine Beetle western United States and part of age. Colorado’s pine forests. Ips beetle MPB, Dendroctonus pon- During the current epidemic usually top-kills a small number of derosae, is the most infamous bark MPB has become more active on pine trees on the landscape. The Ips beetle in Colorado’s forests today. the landscape in response to a num- beetle attacks the smaller diameter MPB is a dark brown to black bee- ber of forest conditions including tle that is 3.5-7 mm in length. This (continued on page 3) even-age stands of lodgepole pine Thousand Cankers Disease Update Thousand cankers disease Front Range communities is chang- Products from black walnuts (TCD) continues to be a concern ing the face of yards, neighbor- include high-quality wood veneer across the United States. Kansas, hoods and parks. The threat of products, fine woodworking mate- Missouri, Michigan and Nebraska TCD to the black walnut in its rial and numerous food and non- have recently authorized quaran- native range in the eastern United food items processed from the nuts, tines on all unprocessed walnut States has serious ecological and bark and leaves of black walnut. material from the western United economic impacts. The CSFS is part of several States. The state of Missouri estimates programs addressing TCD includ- TCD in Colorado is a predomi- a loss of $850 million in wood and ing education and outreach, urban nately urban forestry issue. The nut production if TCD reaches the community response, TCD surveys rapid decline and mortality of native walnut forests of the Eastern and ongoing research efforts at walnuts in many of Colorado’s United States. Colorado State University.

CSFS I&D Quarterly

Firewood and the Spread of Pests and pathogens don’t rec- heating a home in the winter, many lations in place regarding the move- ognize national, state or county Coloradoans enjoy a cheerful blaze. ment of firewood. These regulations boundaries. In today’s global econ- One can find firewood for sale al- target nine forest insects and patho- omy, products including raw wood most everywhere including camp- gens. Colorado does not currently material can rapidly circumnavigate grounds, grocery stores, gas stations have any firewood regulations. the globe. This means that insects and the Internet. In response to a recent proposal and diseases can be moved vast Firewood is also one of the most by the National Firewood Task distances before they are evident; common sources for the introduc- Force, several Colorado agencies these insects and pathogens often tion of exotic pests and patho- including the CSFS have begun find suitable conditions in their new gens. Several of the largest insect working on firewood proposals for locations. and disease threats that Colorado the possible regulation of firewood Firewood is a good example of a faces are commonly transported by movement and increasing outreach Political cartoon from Joe Heller. raw wood material that can travel firewood and other unfinished wood and education efforts. Published here with permission. great distances. Firewood is part of products, including emerald ash Colorado’s forests are very di- many peoples’ daily lives. Whether borer (EAB) and gypsy moth (GM). verse and will likely face threats enjoying a summer campfire or Thirty states currently have regu- (continued page 3) European Elm Flea Weevil The European elm flea wee- and a large hind femur. liation damage is usually heavi- vil, a common weevil through- Adult weevils appear in the est in late spring and early sum- out Europe was first identified in spring and feed on the underside mer. Trees typically recover the northeastern United States in of newly emerging leaves. They even from heavier defoliation the early 1980s. It is now com- feed in a sporadic shotgun pat- events. Repeat defoliation by monly found throughout most of tern giving damaged leaves a European elm flea weevil may the United States including lacy look similar to the damage predispose trees to other biotic Colorado. Its damage signature, caused by the more conspicuous and abiotic stressors. similar to other common insects, adult elm leaf beetle. and small size left it unobserved While the damage to leaves is in many areas for years. very similar to the feeding pat- tern of the elm leaf beetle the European elm flea weevil is a less conspicuous beetle. The Feeding damage caused by the adults have a habit of jumping adult European elm flea weevil. off of leaves. Adult European elm flea weevil lay eggs along the leaf Leaf mining by a European elm veins. The larvae mine the inside leaf flea weevil. Adult European elm flea weevil. of the leaf for several weeks creating a serpentine pattern There are no currently pre- The European elm flea wee- prior to pupating and emerging scribed management control vil is a tiny brown weevil about throughout the summer. strategies for European elm flea 2 mm in length with darker The European elm flea wee- weevil. Several products tar- brown or black splotches with a vil infests American, Siberian, geted at other leaf miners and prominent proboscis, or snout, Chinese and hybrid elms. Defo- defoliators are suggested.

CSFS I&D Quarterly 2

Ask Questions About Firewood ( continued from page 2 ) from insects and pathogens of di- these insects and have helped slow • Where is this wood from? verse origin. At present, the largest their movement into new areas. • Can I buy local? insect and disease risks to Colo- However, states that are currently rado’s forests are EAB and GM. not impacted but at risk need to raise • Can I buy firewood (especially for Despite the fact that EAB and awareness of these threats. camping) at my destination? GM are poor flyers, both insects Two key education messages - • Has the wood been treated (kiln have rapidly spread from their origi- “Don’t Move Firewood” and “Buy It dried, debarked)? nal introduction sites and continue to Where You Burn It” - are meant to • Is it a high risk species (ex. ash)? cause severe economic and ecologi- make people ask questions about the cal damage in impacted areas. EAB firewood they purchase, its origins For more information visit: has recently been detected in Kansas and destinations. Be proactive and City, Mo. Massive education and help prevent the spread of insects http://www.colorado.gov/cs/ Satellite/Agriculture-Main/ outreach campaigns throughout and pathogens into Colorado’s for- Two firewood education and outreach states currently impacted with EAB ests by asking some questions before CDAG/1167928360848 slogans. and GM have raised awareness of you purchase or transport firewood:

The Bark Beetle Trifecta ( continued from page 1 ) portions of a tree trunk, causing the branches, just like MPB girdles a large number of dead and declin- top of the tree to discolor and die. larger diameter stems, causing die- ing pines on the landscape however, Like trees attacked by MPB, trees back. Twig beetles are secondary twig beetles have been found in attacked by Ips beetles are usually insects and are almost always found trees also containing MPB and Ips suffering from additional biotic and in association with other bark bee- beetles. abiotic stressors. Ips beetles are tles like MPB and Ips, whose activ- The Trifecta often found in conjunction with ity in trees allows twig beetle to be It can be very difficult for an other bark beetles. more successful. untrained person to recognize the Kingdom: Animalia During the current MPB epi- small characteristics that separate demic, Ips beetle populations have these bark and twig beetles, espe- Phylum: Arthropoda risen as MPB have increased the cially without equipment to magnify Class: Insecta number of dead and dying pines on the beetles. Several species go com- Order: Coleoptera the landscape. pletely unnoticed because of their Family: # 3 Pityophthorus and size alone. Genera: Dendroctonus Twig beetles belong to several Even with multiple bark and twig Ips genera including Pityophthorus and beetle species active in the lodge- Pityogenes Pityogenes. Twig beetles are minute A twig beetle, . pole and ponderosa pine forests of Pityophthorus dark brown to black beetles that are Colorado, the MPB remains the Others 0.8-3.0 mm in length. Many twig The name twig beetle can be primary agent of tree mortality. Ips beetle species have conspicuous misleading. Twig beetles are not beetle and the various twig beetles Species: Numerous down-turned spines. One twig bee- only found in the small diameter continue to be secondary agents and tle, Pityogenes knechteli (also know twigs and branches. They can use their activity levels in Colorado’s Scientific classification of bark and as Pityogenes plagiatus knechteli), dead and dying material of a larger forests are in response to the in- twig beetles (Curculionidae). received recent press because of its diameter and are sometimes found creased number of dead and dying association with MPB. in the large branches and even in the trees attacked by MPB and other Numerous twig beetle species are trunk of the tree. primary agents of mortality. native to the western United States During the current MPB epi- The Entomologist Mail Bag and are part of Colorado’s forests. demic, twig beetle has received A 4-inch by 6-inch section of Twig beetles are usually found in some of the spotlight. Twig beetle, lodgepole pine recently obtained the small diameter twigs and because of its very small size and from the Steamboat Springs area branches of trees. Their feeding small impact on the forest land- contained four species of bark and patterns girdle these twigs and scape, usually goes unnoticed. With twig beetles! CSFS I&D Quarterly 3

Things to watch for:

• CSFS Quick Guides ◊ Spruce beetle ◊ Thousand cankers disease ◊ Sudden aspen decline • Gypsy moth and emerald ash borer trap vandalism Report missing or damaged traps at 970-491-6303. • Aerial detection survey flights continue through September.

Upcoming events & announcements

August 2010 October 2010 18 - Northern Colorado Pest Group Meeting, Fort 1 - ISA-RMC Annual Conference (cont), Denver Collins 4-8 - Bark Beetle Technical Working Group Meeting, 25 - Denver Metro Pest Group, Denver Rapid City, South Dakota

Colorado State Forest Service September 2010 Colorado State University 16 - Front Range Urban Community Forestry Coun- 5060 Campus Delivery cil, TBD Submissions for I&D Quarterly Report: Fort Collins, CO 80523 17 - Western Colorado Community Forestry Confer- Do you have a FAQ? ence, New Castle Phone: (970) 491-7282 Is there something you want to know more about? 22 - Northern Colorado Pest Group Meeting, Fort Fax: (970) 491-7736 Submit your event or announcement, ask a question or Collins suggest an insect, disease or product to feature: 29 - Denver Metro Pest Group, Denver [email protected]. Email: [email protected] 30 - ISA-RMC Annual Conference, Denver Deadline for submissions is October 15, 2010.

CSFS I&D Quarterly 4