Top 10 Notorious Landscape Pests (and How to Deal With Them) MAHSC Professional Landscape School, 2015 Leaf Chewers Pests that Suck Plant Juices Signs and symptoms Daniel A. Potter, Professor Caterpillars Stippling Bronzed foliage Turf & Landscape Entomology Beetles Sawflies Distortion Thinning Honeydew, sooty mold You Leaf chewers Signs & symptoms Correct Diagnosis is Important! Insects Holes Notches Scraping Frass Pay attention to signs and symptoms Sometimes the signs are right! Pests that Suck Plant Juices Things can look similar but somehow be different. Lace bugs Mites Aphids Psyllids Scale insects 1
Choose the Right Solution! Dealing with Tent Caterpillars #8 Bagworms Major Pest of Landscape Evergreens Scrape off egg masses Remove nest by hand Knock out with long stick Blow out with water hose 9 & 10: Web making Caterpillars Bagworms Behaving Badly! Eastern tent caterpillar Fall webworm Fall webworms are easy to deal with! Web making Caterpillars Mimosa webworm Pest of Honeylocust! Female bagworm is wingless, legless; never leaves her bag Adult male is a furry moth that emerges in late summer 2
S A W F L Y Bagworms mate in late summer Female Pyrethroids Are Very Effective Against Caterpillar Pests Sawfly larvae look like caterpillars, but they are not the same! Male Female lays eggs in her bag, where they overwinter Eggs hatch, young bagworms begin feeding in May Reduced-Risk Products for Turf Caterpillars Sawflies versus caterpillars Sawfly: 6 or more pairs of fleshy abdominal prolegs (enough to spell SAWFLY) No little hooks on prolegs Caterpillar: 5 or fewer pairs with little hooks Bagworm Control Tips Two other Leaf Chewers Sawfly larvae behaving badly Handpick bags with egg masses (Sept. to April) Target small larvae with insecticide (late May or June) #7 Sawflies #6 Japanese Beetles 3
Top 10 Landscape pests #6 Japanese Beetles Sawfly pupal cases (present in winter) Sawfly adult Roseslug a Sawfly! July 8 July 18 Japanese Beetle Damage to Linden Tree, Lexington, KY, 2007 Controlling Sawflies Effective sprays include: Acelepryn Provaunt Pyrethroids Or, prune out small infestations! Japanese beetles damage many plant species! Highly susceptible: Most lindens Purple leaf plum Purple sandcherry Norway & Jpn. maple Roses Certain crabapples Resistant: Red maples Dogwoods Redbud Beech Tuliptree Sweet gum 4
Japanese beetle adult control #5 Boxwood Leafminer Acelepryn (4 weeks residual) Pyrethroids Onyx (4 weeks) Talstar (2 3 wks) Scimitar Tempo Sevin (1 2 weeks residual) Systemics Blister like mines Early sign pale halos Larvae (maggots) in leaf Organics for Japanese Beetle (5 7 day protection) There s a Sucker Born Every Minute # 4: Various small sucking pests Test Plant Trap Aphids Mites Trap placement was evaluated in 24 home landscapes Untreated Treated Untreated Treated Lace bugs Psyllids #5 Boxwood Leafminer Honeydew Sucking beak like a syringe Adult flies emerge during spring leaf flush Female lays eggs in soft expanding leaves Stippling Distortion Sooty mold 5
Lace Bugs Pests!! Lacewings Beneficial predators!! Aphids Organic Aphid Control Insecticidal soap or horticultural oil Brisk water stream from hose Woolly beech aphid Lace bugs damage many plants: Aphid damage: Curled, cupped leaves; sticky honeydew; sooty mold, reduced vigor, disease Systemics work well for aphids, lace bugs, psyllids, and boxwood leafminer Sycamore Oak Hawthorn Pyracantha, cotoneaster, andromeda Azalea Lace Bugs Azalea Boxwood Psyllid Damage occurs during spring leaf flush Do You Know Your Aphid Natural Enemies? Warm Season Spider Mites Lady beetle Lady beetle larva Twospotted spider mite European red mite Cool Season Spider Mites Boxwood spider mite Lacewing larva Mummy (parasitized) Spruce spider mite Southern red mite Maple spider mite 6
Neonicotoids can flare mite problems on woody landscape plants Stimulates mite egg laying Kills natural predators Stippling Loss of chlorophyll Fine webbing Armored scales encrust branches or leaves; cause dieback and death of plant Beating foliage over paper to dislodge and detect mites Haircut for Potter s bug lectures Obscure scale on pin oak Armored Scales Form a Shell-like Cover Mite Control Tips: Use a Miticide! (Most insecticides won t work for mites) Good ones include: Akari, Avid, Floramite, Forbid, Hexygon, Kontos, Promite, Pylon, Shuttle, Sanmite, TetraSan, Ultiflora # 2: Scale Insects Armored Scales Soft Scales Oystershell Scale Attacks lilac, maple, willow, apple, hawthorn, dogwood, others 7
Pine Needle Scale Other Tricks for Managing Scale Insects Soft scale damage: Sticky honeydew Sooty mold Crown thinning, dieback Black sticky electrical tape monitors crawler hatch Gentle scrubbing Stiff water spray Euonymus Scale Scale Insect Control: Scale Control by Ant Exclusion Crawler sprays Distance and Talus are good choices Systemic treatments Usually more effective against species that infest leaves than those on twigs Ants tend soft scales to get sugary honeydew, while defending their livestock from predators Soft Scales lack detachable cover The body resembles an inverted, leathery bowl Timing Scale Crawler Hatch by Plant Bloom: When ants were excluded, predators reduced calico and magnolia scale densities by 60 80%! Cottony maple scale Magnolia scale Soft Scales Calico scale Oystershell scale coincides with full bloom of Sargent crabapple Euonymus scale coincides with 50% bloom of Kousa dogwood Sticky band to exclude ants 8
#1: Borers in Trees and Shrubs Common clearwing borers Lilac Borer Peachtree and Lesser Peachtree borers Clearwing borer Flat headed borer Dogwood borer Banded ash borer Clearwing borers expel frass from cracks in the bark Some Borer Prone Woody Plants Pupal case of clearwing borer moth that has emerged Dogwood Lilac Flowering cherry and plum White birch Ash Recently transplanted or stressed hardwood trees Clearwing borer larvae are whitish caterpillars with a brown head Clearwing (moth) Borers Cleawing Borer symptoms Controlling Clearwing borers Apply preventive bark spray when adults begin to emerge and lay eggs Effective products: Lilac Borer Moth Dogwood Borer Moth Crown Thinning & Dieback 9
Stressed trees attract borers! Plant Health Care helps prevent them Controlling flatheaded borers in small trees Apply preventive bark spray when adults begin to emerge and lay eggs Effective products: Bronze Birch Borer Flatheaded apple tree borer Flatheaded Borers Adults are flattened, metallic colored beetles Larvae flattened Do not plant European white birch North American birches (paper or canoe birch, gray birch) are less susceptible but still attacked Timing Borer Control By Plant Bloom (Examples): Lilac borer: Common lilac; full bloom Dogwood borer: Oakleaf hydrangea; first bloom Bronze birch borer: America holly, first bloom Winding tunnels under bark girdle the branches and trunk River birch is resistant! Flat headed borers leave D shaped holes when adult emerges Flatheaded appletree borer also attacks many species of stressed landscape trees Crabapples, maples, hawthorn, dogwood, many others are susceptible Emerald Ash Borer Newly transplanted trees Stressed trees 10
Emerald Ash Borer Toledo, Ohio, USA Systemic insecticides for Emerald Ash Borer Rule of thumb: Under 30% canopy dieback, tree can be saved Before (2006) After (2009) 2 3 year s protection 1 year protection Tree can still be saved Too far gone to save Emerald Ash Borer Some systemic insecticides can also be applied as trunk sprays Advantage: Fast and non invasive You Thinning, dieback Tunnels under bark Suckering D shaped holes Insecticide translocated upward to where pest feeds Insects Emerald Ash Borer Attacks & kills all sizes and species of ash Systemic Treatments CAN Protect Trees from Emerald Ash Borer Not Treated Two Great Websites for More Information Not Treated Treated Bowling Green State University golf course 11
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