FOREST INSECT & DISEASE ISSUES IN ORNAMENTAL TREES GENERAL COMMENTS The distinction between “wild/native” and “ornamental” is fuzzy TRA Native forest plant values tend to be low, PEST MANAGEMENT WORKSHOP GRAND JUNCTION, CO which dictates fewer options & tactics FEBRUARY 2012 Likewise, higher-value ornamentals with issues may warrant action more often Many ornamental causal agents are typical of the surrounding forest (i.e., mobile) Dave Leatherman [email protected] Climate change influence on all of this is real and requires constant observation DOMINATE ISSUES IN THE NATIVE INSECTS AND FIRE FORESTS OF COLORADO Wild or out-of-prescription fire fires can create “habitat” for insects in the form of bark beetles dead or stressed trees Insect-caused mortality regional defoliators like budworm may lead to temporarily deer and elk increased ignition potential and fuel-loading borers Prescribed fire can be used to dispose of dwarf mistletoe susceptible or insect- infested woody debris decay FIRE MITIGATION REDUCTION OF Slash creation could SLASH INSECTS invite pest issues Ips beetle such as ips, twig PROMOTE DRYING (CHIPPING OR LOPPING-AND- beetles, and even SCATTERING IS BETTER THAN PILING) rodents IF PILES ARE PRODUCED, PLAN TO BURN PRIOR TO EMERGENCE OF BARK BEETLES Monitor stems TRY NOT TO PRODUCE SLASH DURING FLIGHT PERIODS Change timing of (Dendroctonus especially) actions if build-up BEST TIME TO CUT IS USUALLY LATE FALL-EARLY WINTER of pests noted REMOVAL FROM SITE IS ANOTHER OPTION 1 MOVEMENT OF BARK BEETLES FIREWOOD MOVEMENT IN FIREWOOD RULES OF THUMB *BARK BEETLE EXTERNAL EVIDENCE + NO EXIT HOLES = DANGER *EXTERNAL EVIDENCE + EXIT HOLES = OK *EXTERNAL EVIDENCE = PITCH TUBES, BORING DUST, WOODPECKERING, AND/OR CROWN FADING (AND, OF COURSE, LIVE LIFE STAGES UNDER THE BARK) MOUNTAIN PINE BEETLE Covered in detail in “Forest Pest Control” session (tomorrow, presenter: Roy Mask) Main “Green Industry” activity is preventive spraying Other activities might include: Identifying infested trees Removing infested trees Thinning of live forests Planting of replacement trees ENTRY EXIT OTHER BARK BEETLES RED TURPENTINE BEETLE (Dendroctonus valens) Attacks only the Secondary pine species (Ips spp., twig lower 3 feet of beetles, Red Turpentine Beetle) trunk Large red adults Douglas-fir species (Douglas-fir Beetle, Big pitch tubes Douglas-fir Pole Beetle, Scolytus spp.) Often occurs Spruce Beetle following fire Aspen Bark Beetles injury, grade change, root Fruit Tree Bark Beetles damage 2 IDENTIFICATION OF IPS EXTERNAL IPS INFESTATION CLUES Rarely does ips produce pitch tubes Most common sign is boring dust in little piles within Various species range from 1/16 to ¼ inch long (i.e., some as big as MPB) bark crevices CO has at least 14 spp., most in pine, some in spruce Woodpecker Adults all have spiny back ends (as opposed to rounded back activity may ends of Dendroctonus spp.) indicate where the problem trees are IPS GALLERIES TWIG BEETLES VERY SMALL, Multiple females MANY SPECIES involved, thus each USUALLY IN BRANCH ENDS gallery is branched or INDICATE WATER STRESS forked (result is a “Y” CAN BE IN TRUNKS OF or “X” pattern) TRANSPLANTS AFTERMATH OF OTHER Galleries made by BARK BEETLE EPIDEMICS adults usually clear CAN INCLUDE A BRIEF of frass OUTBREAK OF THESE PINE TWIG BEETLES TWIG BEETLES MOST IN THE GENUS Pityogenes sp. PITYOPHTHORUS USUALLY DO NOT REQUIRE TREATMENT* CAN BE AN INDICATOR OF DRY CONDITIONS *Transplants are the exception Pityophthorus sp. 3 DOUGLAS-FIR BEETLE BARK BEETLES OF DOUGLAS-FIR (Dendroctonus pseudotsugae) Although related to Douglas-fir Beetle MPB, not nearly as Restricted to large-diameter trees aggressive Attacked trees often set-up by fire or drought Rogaine user? Douglas-fir Pole Beetle Likes large-diameter Likes 6-10” diameter trees (i.e., “poles”) blowdown, fire- charred trees, Engraver Beetles in the genus Scolytus drought, and trees Like “Ips” in pines, often secondary, may stressed by budworm occur in all sizes of trees, often with the Photo by Contech defoliation above Flies in early summer SPRUCE BEETLE SPRUCE BARK BEETLES (Dendroctonus rufipennis) Spruce Beetle (requires large-diameter trees, outbreaks usualy start with a wind event blowing down areas of trees, can be a major influence on the landscape) Spruce Ips (at least 3 species: one in Likes standing, big, spruce near a stream blue spruce in urban areas can be Likes fresh windthrown spruce somewhat troublesome, others in forest Epidemics start in blowdown and move into standing trees situations are usually not serious) Major outbreaks in CO in the late 1940s (Trapper‟s Lake) and late 1990s (nw of Steamboat Springs) Other minor species (twig beetles, etc.) Presently active on Grand Mesa, elsewhere in w CO THE “BLOWDOWN” BARK SPRUCE BEETLE BEETLE SIGNS AND SYMPTOMS FINISHED HERE STANDING “FADER” STARTED HERE PITCH TUBES GALLERIES Area near Clark, Routt County CO. 1997 NEEDLE DROP 4 MORE SPRUCE BEETLE TRUE FIR BARK BEETLES BIOLOGY Balsam Bark Beetle - in genus Sometimes produces runny pitch tubes, (Dryocoetes, pronounced “dry-o-see’-teez” sometimes coagulated acts in concert with root disease fungi and ones. can result in large-scale mortality of high- elevation stands under moisture stress Crown discoloration of infested trees is Fir Engraver (Scolytus ventralis) can difficult to detect cause widespread top-kill and whole tree mortality 3-toed woodpecker is primary avian predator Other minor species BALSAM BARK BEETLE (Dryocoetes confusus) BALSAM BARK BEETLE EGG GALLERY Distinctive “stellate” pattern Note central nuptial chamber Female egg galleries (6 plus a partial 7th) radiate males (top), females (bottom) from the mating area by Jeff Witcosky of USFS Staining fungus Ophiostoma dryocoetidis Affecting subalpine fir (Abies lasiocarpa) statewide in involved in beetles‟ Usually acts in consort with root disease fungi such as Armillaria and success Fomes (together, called “SUBALPINE FIR DECLINE”) Prime suspect as being a consequence of climate change FIR ENGRAVER CEDAR BARK BEETLES (Scolytus ventralis) Ecologically similar to Ips in pine and Found only in spruce junipers and Usually only found Eastern Red Cedar in stressed white fir in our area Often attacks Require upper trunk first considerable stress Egg galleries are (usually lack of horizontal adequate water) Has been a an Galleries distinctive issue n of Durango We have 4 spp. 5 URBAN BARK BEETLES OF DECIDUOUS HOSTS ELM BARK BEETLES ELM Smaller Eur. Elm Bark Beetle (Scolytus multistriatus) Banded Elm Bark Beetle (Scolytus shevyrewi) ASH Ash Bark Beetles (few species in genus Hylesinus) HACKBERRY Hackberry Bark Beetle (Scolytus muticus) FRUIT TREES Shot-hole Borer (Scolytus rugulosus) Smaller European Elm BB Banded Elm BB ASPEN From Europe 100+ years Recently from Asia Two minor, unaggressive species Being replaced by BEBB? Now the default elm bb BLACK WALNUT Has been the major vector of Apparently a poor DED vector Walnut Twig Beetle (Pityophthorus juglandis) DED in NA ELM BARK BEETLE GALLERIES ASH BARK BEETLE SIGNS AND SYMPTOMS SMALLER EUROPEAN BANDED ASH BARK BEETLE SHOTHOLE BORER (Scolytus rugulosus) Essentially our only bark beetle in fruit trees (cherry, plum, peach, etc.) Usually stress is the problem, not these bark beetles Paying attention to water/borer issues is best prevention WITH BARK WITHOUT BARK 6 ASPEN BARK BEETLES (2 spp.) WALNUT TWIG BEETLE Vector of Thousand Canker Disease fungus (Geosmithia morbosum) New to CO How did they get here? Nothing known to date to stop them Native to Mexico and Southwest U.S. BARK BEETLE INFO AVAILABLE FROM CSU/CSFS WESTERN SPRUCE BUDWORM CSU Cooperative Extension Fact Sheets MOST IMPORTANT 5.563 “Firewood & House Log Insects” FOREST DEFOLIATOR 5.558 “Ips Beetles” IN CO 5.528 “Mountain Pine Beetle” DOUGLAS-FIR IS 2.948 “Pinyon Pine Diseases & Insects” FAVORED HOST Garden Insects of North America (book) CAN KILL TREES CSU Bioag Sci. and Pest Mgmt. Dept. website WITH 3+ YEARS OF Outreach and Extension HVY. FEEDING Thousand Cankers Disease/Walnut Twig Beetle PRESENTLY ACTIVE IN SAN JUAN AND LA “Whitney for President” GARITA MOUNTAINS WSBW EGG MASSES HOW DO BUDWORMS COPE OUT THERE IN FEBRUARY? Very tiny larvae live in shelters called OLD “hibernaculae” up in FRESH the tree crowns USED TO PREDICT POPULATIONS LAID IN EARLY SUMMER ON NEEDLES GREEN ONES ARE FRESH GRAY ONES ARE OLD AND HATCHED EACH MASS CONTAINS DOZENS OF EGGS 7 WSBW LARVA WSBW DEFOLIATION STARTS AT TOP OF EARLY TREE SUMMER STARTS AT BRANCH MINES OLD ENDS NEEDLES OCCURS IN EARLY THEN IN SUMMER BUDS CAN RESULT IN TOP- THEN IN KILL OR MORTALITY NEW NEEDLES WSBW TREATMENT TIMING WSBW AERIAL SPRAYING WILL BE RARE IN SPRAYING IS NOT ALWAYS NEEDED THE FUTURE BUT WHEN IT IS, BEST DONE TIMING IS WITH Bacillus CRITICAL thuringiensis BEST TIME IS PRODUCTS (low WHEN BUDBREAK impact on non- IS OCCURRING target species) FOR THE MOST- VALUABLE HOST MOST ECONOMICAL WAY TO TREAT BIG AREA TIGER MOTH PINE SAWFLIES Chew mostly “old” needles Longterm defoliation gives trees “tufted” appearance (needles at ends of branches OK, interior needles Forms a white tent at the very top gone) of various conifers Female has sawlike egg-laying organ, Larvae active in winter, stay in tent deposits eggs inside Larval hairs irritate skin needles May kill tree tops, at most Tend to like smallish Has been an issue in p-j near trees, often open-