Biological Control of What is Biological Weed Control? DALMATIAN TOADFLAX GORSE Linaria dalmatica Ulex europaeus Invasive noxious weeds in Oregon cost millions of dollars It is important to make sure the correct species of biocontrol Key to Biocontrol Agent Status Noxious Weeds in Oregon in economic and environmental damage. Biological agents are released, to use the most effective species, and to Gorse seed weevil control is a tool vegetation managers employ to help The following general information is provided for each document the release and establishment of weed biocontrol Exapion ulicis naturally suppress weed infestations. This pamphlet agents. biocontrol agent. shows many of the common biological agents you may Year: 1956 Distribution: Widespread A guide to common biological Since 1947, 77 species of biocontrol agents have been released Year: Year of introduction. encounter in Oregon. Attack rate: Heavy Control: Good control agents found in Oregon in Oregon against 32 species of targeted weeds. A total of Distribution: Distribution of agent in host infested counties. Collectability: Mass Release No. 100 Classical biological control is the use of selected natural Dalmatian toadflax stem weevil 67 species are established. The majority of the bioagents Widespread >50% Limited <50% Timing: Apr–May Method: Sweep net/ enemies to control targeted weeds. Most of our worst are (71), plus three mites, one nematode, and two Mecinus janthiniformis racquet Stage: Adult Comment: No need for Attack rate: noxious weeds originated from other continents. pathogens. Successful projects can generate 15:1 benefit to Percent of plants attacked. Year: 2001 Distribution: Widespread redistribution. Prospective biocontrol agents are thoroughly tested to cost ratios. There are a number of non-approved natural Heavy >70% Medium >30% Light >10% Slight <10% Attack rate: Heavy Control: Excellent ensure they will be safe to release in North America. enemies found on some weeds. Biocontrol agents are listed Control: Observed reduction of weed density or seed Collectability: Mass Release No. 100 Once approved, they are released at nursery sites where here under host weed, type of agent, and scientific name. Timing: May–Jun Method: Sweep net/racquet they can establish resident populations. Surplus bioagents production. Stage: Adult Comment: Stand reductions at many Generally, the Oregon Department of Agriculture (ODA), are later harvested and released at other infestations Poor: little change <10% Fair: noticeable change >10% sites. A sibling species M. janthinus attacks yellow the USDA Plant Health Inspection Service (APHIS), throughout Oregon. It may take several years for their Good: significant control <90% Excellent >90% control toadflax. and cooperators can provide needed biocontrol agents at populations to reach levels that effectively control the Collectability: no cost. Whenever approved biocontrol agents are shipped Availability of agents for redistribution. target weeds. across state lines, a PPQ 526 permit from APHIS is required. Mass—available for mass collection. FIELD BINDWEED Biocontrol agents rarely eradicate entire infestations. Parties interested in implementing biocontrol are encouraged Limited—available in limited numbers or difficult to collect. Convolvulus arvense The goal is to weaken weeds so desirable vegetation can to contact ODA or APHIS to determine the availability and N/A—not available at this time. Gorse spider mite Field bindweed gall mite Tetranychus lintearius compete and suppress the weeds below an economically need for biocontrol agents of specific weeds. Release number: Recommended minimum number to Aceria malherbae or environmentally damaging level. Biocontrol works establish a new colony. Year: 1994 best when integrated with land management practices Nontarget Impacts Distribution: Widespread Timing: Year: 1999 that improve desirable competitive vegetation. Even after Optimum time of year to redistribute. Distribution: Widespread Attack rate: Light Most weed biocontrol agents are safe to use throughout control, some weed infestations may rebound. Generally Life stage: Attack rate: Heavy Control: Poor Oregon. However, the thistle seed head weevil Rhinocyllus Life stage of biocontrol agent best suited for Collectability: Limited resident biocontrol agent populations regain control collection and establishment. Control: Good after several years. Biological control requires a long- conicus (see below) was found to attack native thistles a Collectability: Mass Release No. 500 term commitment to weed management and may not be decade after its introduction in 1979. It is therefore not Method: Preferred method to collect agents from Release No. 1000 Timing: Aug–Sep recommended for use as a biocontrol agent of thistles. well-established populations. Timing: Jun–Sep Method: Harvest infested suitable at all infestations. plant material ODA curtailed redistribution of this weevil in 1989 due to its Sweep net—heavy duty canvas net to dislodge agents from Method: Harvest Biocontrol agents affect weeds by either directly targeting Stage: All impact on native thistles. USDA APHIS restricted interstate vegetation, can be used in conjunction with a racquet. Stage: All plant tissues through their removal or destruction, or Comment: Ineffective movement of the weevil in 2000. Current protocols for host Aerial net—lightweight net for fragile flying insects. Comment: Mostly in indirectly by causing galls, that interfere with tissue Northeastern Oregon. Use about one sandwich bag of due to predatory mite. specificity testing would have prevented the introduction of Aspirate—special aspirator to suck insects into a vial. functions and stress the plants. infested plant material. Look for gnarled leaves. Multiple generations per this weevil. The weevil is widespread and commonly found Beating sheet—knock insects off plants with a racquet onto year. on bull, Canada, Italian, milk, musk, and slenderflower Benefits of biological control include: host specific canvas sheet and collect with aspirator. Field bindweed to target weed, self-perpetuating populations, thistles. It has however, significantly controlled weedy thistles Hand pick—collect by hand. synchronization with target weed lifecycle, ability at various locations in Oregon. Light trap—UV light to attract night flying insects to white Tyta luctuosa to locate host plants in variable environments, and sheet or funnel trap. Year: 1998 economic feasibility on low-value lands. Vacuum—motorized vacuum to suck insects from plants. Distribution: Limited Attack rate: Light Some of the disadvantages of biological control include: Harvest—collect infested plant materials (i.e. galls, seed heads, roots which can be released or rear agents out). Control: Poor slow rate of impact, dependence on minimum weed Collectability: Limited density, fluctuating availability of agents, and limited Release No. 50 efficacy in variable environments. Timing: Jun–Sept Method: Aerial net Stage: Adult Comment: Flush adults and sweep net, one to two Adult weevil and egg sites (brown bumps) on thistle bracts (R). adults per vial. Mostly in Willamette Valley.

KNAPWEED, DIFFUSE KNAPWEED, RUSSIAN for more information diffusa Acroptilon repens = Rhapanticum repens KNAPWEED, MEADOW Knapweed root weevil Knapweed seed head moth Russian knapweed gall wasp Centaurea jacea x nigra = C. moncktonii Cyphocleonus achates Metzneria paucipunctella Aulacidea acroptilonica Oregon Department of Agriculture Year: 1993 Year: 1981 Year: 2014 (ODA) KNAPWEED, SPOTTED Distribution: Limited Distribution: Widespread Distribution: Limited = C. maculata Attack rate: Heavy Attack rate: Light Control: Fair Attack rate: Slight Noxious Weed Control Program Control: Fair Collectability: Limited Control: Unknown 635 Capitol St. NE Sulfur knapweed root moth Collectability: Mass Release No. 200 Collectability: N/A Agapeta zoegana Release No. 50–100 Timing: March Release No. 50 Salem, OR 97301 Timing: Aug–Sept Method: Harvest seed heads Timing: May–Aug www.oregon.gov/ODA Year: 1987 Method: Hand pick Stage: /pupa Method: Harvest Stage: Pupa Distribution: Widespread Stage: Adult Comment: Displaced by seed Banded knapweed Comment: Collect bouquets (503) 986-4621 Attack rate: Heavy Comment: Collect adults head weevils. Ineffective, often seed gall of infested plants. All female Control: Good under rosettes. Disperse upon release. parasitized. species. May become available Collectability: Limited soon. ODA biocontrol projects Release No. 50–100 Year: 1975 Timing: July Knapweed root http://go.usa.gov/39rkG Sphenoptera jugoslavica Distribution: Method: Light trap Stage: Adult Widespread Comment: Hard to collect in sufficient number. Year: 1980 Attack rate: Heavy Distribution: Widespread Control: Good Biocontrol release form Broad-nosed knapweed Lesser knapweed Attack rate: Heavy Collectability: Mass http://go.usa.gov/39rkz seed head weevil flower weevil Control: Fair Release No. 100 Bangasternus fausti minutus Collectability: Limited Timing: Jun–Aug Method: Aerial net Year: 1992 Release No. 100 Stage: Adult Comment: Little need for redistribution. USDA APHIS PPQ Year: 1989 Timing: Jun–Jul Method: Sweep net Stage: Adult Produces hard gall. Distribution: Widespread Distribution: Widespread Comment: Low density, hard to collect. Larva most Airport Business Center Attack rate: Heavy commonly encountered. Control: Good Attack rate: Heavy UV knapweed seed gall fly 6135 NE 80th Ave. Suite A-5 Collectability: Mass Control: Excellent Urophora quadrifasciata Collectability: Mass Release No. 100 Russian knapweed gall midge Portland, OR 97218 Release No. 100 Year: 1975 Timing: Jun–Jul Timing: Jun–Jul Method: Sweep net/racquet Jaapiella ivannikovi (503) 326-2814 Stage: Adult Comment: Best at 20% bloom. Distribution: Widespread Method: Sweep net/racquet Stage: Adult Attack rate: Heavy Year: 2011 Comment: Best when flowers are in bud stage. Best control on diffuse knapweed. Control: Good Distribution: Limited USDA APHIS PPQ permit 526 Collectability: Mass Attack rate: Medium Knapweed peacock seed fly Blunt knapweed flower weevil Release No. 100 Control: Fair http://go.usa.gov/cSMGk acrolophi Larinus obtusus Timing: Jun–Aug Collectability: Mass Green knapweed seed fly Method: Aerial net Release No. 20–50 Year: 1993 Year: 1942 Terellia virens Stage: Adult Timing: May–Aug Information compiled by: Distribution: Limited Distribution: Widespread Comment: Little need for Method: Harvest Stage: Pupa Eric M. Coombs, Oregon Department of Attack rate: Light Control: Fair Attack rate: Heavy Year: 1993 redistribution. Produces Comment: Collect bouquets of Collectability: Limited Control: Excellent Distribution: Limited soft gall. infested plants with mature galls. Agriculture; Wyatt Williams, Oregon Department Release No. 100 Timing: Jun–Jul Collectability: Mass Attack rate: Medium of Forestry; and Colin Park, United States Method: Aerial net Stage: Adult Release No. 100 Control: Good Department of Agriculture, Animal Plant Health Comment: Gently sweep during Timing: Jun–Jul Collectability: Limited Inspection Service. bud stage, aspirate from net. Best Method: Sweep net/racquet Release No. 100 at moister sites. Stage: Adult Timing: Jun–Jul Method: Aerial net Stage: Adult Created: June 2015 Layout & design by: Liz Beeles Comment: Best at 20% bloom. Comment: Gently sweep during bud stage, aspirate Abundant on meadow knapweed. from net. Best at moister sites. LEAFY SPURGE MEDITeRRANEAN SAGE RUSH SKELETONWEED ST. JOHNSWORT Euphorbia esula Salvia aethiopis Hypericum perforatum Black leafy spurge flea beetle Mediterranean sage Rush skeletonweed Rush skeletonweed St. Johnswort root borer St. Johnswort leaf Aphthona lacertosa crown/root weevil root moth bud gall mite Agrilus hyperici Year: 1993 Phrydiuchus tau gilveolella Eriophyes chondrillae Year: 1986 Chrysolina hyperici Distribution: Widespread Year: 1971 Year: 2005 Year: 1978 Distribution: Limited Year: 1947 Attack rate: Heavy Distribution: Widespread Distribution: Limited Distribution: Widespread Attack rate: Heavy Distribution: Widespread Control: Excellent Attack rate: Heavy Attack rate: Light Attack rate: Heavy Control: Excellent Attack rate: Heavy Collectability: Mass Control: Good Collectability: Mass Release No. 100 Control: Unknown Control: Excellent Collectability: Mass Control: Excellent Release No. 500 Timing: Jul, Oct–Nov Method: Sweep net, aspirate Collectability: Limited Collectability: Mass Release No. 50–100 Collectability: Mass Timing: Jun–Jul Stage: Adult Comment: Sweep at 50% bloom or Release No. 50-100 Release No. 1000 Timing: Jun–Jul Release No. 100 Method: Sweep net aspirate from fall rosettes. Timing: Jun–Aug Method: Aerial net Stage: Adult Timing: Jun–Aug Method: Sweep net/racquet Timing: Jun–Jul Stage: Adult Comment: Import from Idaho. Flush adults and net. Method: Harvest Stage: Adult Method: Sweep net Comment: Mixed with PUNCTUREVINE Stage: All Comment: Collect bouquets of galled Comment: Collect at >50% bloom. Best at drier sites. Stage: Adult Comment: Most common in Western similar species A. czwalinae. Best at wetter sites. Rush skeletonweed plants. Inoculate with infested sprigs. Spotty availability. Oregon. May be mixed with C. quadrigemina. Tribulus terrestris gall midge Black-dot leafy spurge beetle Cystiphora schmidti Rush skeletonweed St. Johnswort looper St. Johnswort leaf Puncturevine seed weevil rust fungus Aplocera plagiata beetles Aphthona nigriscutis Microlarinus lareynii Year: 1978 Puccinia chondrillina Chrysolina quadrigemina Year: 1989 Distribution: Widespread Year: 1989 Year: 1963 Attack rate: Heavy Year: 1978 Distribution: Widespread Distribution: Widespread Distribution: Limited Year: 1948 Attack rate: Heavy Control: Good Distribution: Widespread Attack rate: Medium Distribution: Widespread Attack rate: Medium Collectability: Mass Attack rate: Heavy Control: Poor Control: Excellent Control: Fair Attack rate: Heavy Collectability: Mass Release No. 250 Control: Good Collectability: Mass Control: Excellent Collectability: Mass Timing: Jun–Aug Collectability: Mass Release No. 100–200 Release No. 500 Release No. 100 Collectability: Mass Timing: Jun–Jul Method: Harvest Release No. 1 bouquet Timing: Jun–Jul Release No. 100 Timing: Aug–Sep Method: Aspirate Stage: Adult Stage: Pupa Timing: May–Jun Method: Sweep net/racquet Method: Sweep net Comment: Not cold winter hardy. Common in Rogue Timing: Jun–Jul Method: Sweep net Stage: Adult Comment: Collect bouquets of galled plants. Heavily Method: Harvest Stage: Spore Stage: Larva Stage: Adult Comment: Most common in Eastern Valley. Look for oval feeding scars under stems and parasitized. Plants may appear purple. Comment: Collect bouquets of infested plants. Comment: Release 2-3 larvae Comment: Best at dry pitting on goatheads. Oregon. May be mixed with C. hyperici. sites. Often mixed with other Photo: UGA 5083047 per square yard. species A. cyparissiae and A. flava. PURPLE LOOSESTRIFE SALTCEDAR Lythrum salicaria Tamarix ramosissima Redheaded leafy spurge borer Oberea erythrocephala Black-margined loosestrife Purple loosestrife Purple loosestrife Saltcedar beetle Year: 1982 leaf beetle root weevil seed capsule weevil Diorhabda carinulata Distribution: Galerucella calmariensis Hylobius transversovittatus Nanophyes marmoratus Widespread Year: 2003 Attack rate: Heavy Golden loosestrife leaf beetle Year: 1992 Year: 1994 Distribution: Widespread Control: Good Galerucella pusilla Distribution: Widespread Distribution: Widespread Attack rate: Heavy Collectability: Mass Attack rate: Heavy Attack rate: Medium Control: Excellent Year: 1992 Control: Good Control: Fair Collectability: Mass Release No. 100 Distribution: Widespread Timing: Jun–Jul Collectability: Limited Collectability: Mass Release No. 500 Attack rate: Heavy Release No. 100 Timing: Jul–Aug Release No. Mass Timing: Jul Timing: Jul–Aug Method: Sweep net/racquet Method: Sweep net Control: Excellent Stage: Adult Method: Handpick Stage: Adult Method: Sweep net/beating sheet Stage: Adult Stage: Adult Comment: Release in one spot. Collectability: Mass Release No. 500 Comment: Difficult to collect. Adults are nocturnal. Comment: Collect from flowering plants. Adults congregate. Interstate shipment prohibited. Comment: Look for dying upper stems. Timing: May and Jul Method: Sweep net/racquet Attacks larger plants. Best reared from infested roots. May be limited by leaf beetle competition. Originally released as D. elongata. Two generations Stage: Adult Comment: Collect during breeding. per year. May be mixed species. Release at one spot.

SCOTCH BROOM TANSY RAGWORT THISTLE, BULL THISTLE, ITALIAN YELLOW STARTHISTLE Cytisus scoparius Senecio jacobaea = vulgare pycnocephalus Tansy ragwort seed head fly Bull thistle THISTLE, MUSK Yellow starthistle bud weevil Yellow starthistle seneciella seed head fly Carduus nutans Bangasternus orientalis flower weevil Urophora stylata Larinus curtus Year: 1966 THISTLE, SLENDERFLOWER Year: 1985 Distribution: Widespread Year: 1988 Distribution: Widespread Year: 1992 Attack rate: Light Distribution: Widespread Carduus tenuiflorus Attack rate: Light Distribution: Widespread Control: Poor Attack rate: Heavy Control: Poor Attack rate: Heavy Collectability: Mass Control: Good Thistle seed head weevil Collectability: Limited Control: Excellent Release No. 100 Collectability: Mass Release No. 100 Collectability: Mass Scotch broom seed beetle Timing: Aug Release No. 50 Timing: May–Jun Release No. 100 Bruchidius villosus Method: Harvest Timing: Nov–Mar Year: 1979 Method: Sweep net Timing: Jul–Aug Stage: Pupa Method: Harvest Distribution: Widespread Stage: Adult Year: 1998 Distribution: Widespread Method: Sweep net Comment: Little need for Stage: Pupa Attack rate: Heavy Comment: Has been mostly displaced by other Stage: Adult Attack rate: Heavy Control: Good further redistribution. Look for spittle on seed heads. Comment: Collect galls in fall. Spread out at new site. Control: Good biocontrol agents. Best at bud stage. Collectability: Mass Release No. 100 Comment: Limited in Western Oregon. Use bouquets of infested seed heads. Collectability: Mass May be diseased, interstate movement prohibited. Timing: May–Jun Method: Sweep net/racquet Release No. 100 Yellow starthistle seed fly Stage: Adult Comment: Little need for THISTLE, CANADA Timing: May–Jun redistribution. Also attacks French broom. Tansy ragwort flea beetle Cirsium arvense Method: Sweep net/racquet Chaetorellia australis, C. succinea Yellow starthistle seed head gall fly Look for eggs on seed pods. Longitarsus jacobaeae Stage: Adult Year: 1988 Urophora sirunaseva Comment: Not recommended, attacks many native Year: 1971 Canada thistle stem weevil Distribution: Widespread Year: 1985 Ceutorhynchus litura thistles. Interstate shipment prohibited. Common on Attack rate: Heavy Distribution: Widespread Distribution: Widespread all weedy thistles. Attack rate: Heavy Control: Excellent Attack rate: Light Year: 1981 Collectability: Mass Control: Excellent Distribution: Limited Control: Poor Collectability: Mass Thistle crown/ Release No. 100 Collectability: Limited Attack rate: Heavy Timing: May–Jun Release No. 100 Control: Good root weevil Release No. 100 Timing: Oct–Nov Trichosirocalus horridus Method: Aerial net Timing: May–Jun Collectability: Mass Stage: Adult Method: Vacuum Release No. 100 Method: Aerial net Stage: Adult Year: 1994 Comment: Aspirate from net. Adventive sibling Stage: Adult Scotch broom Timing: Apr–May Distribution: Limited species C. succinea most common (pictured). Photo: UGA 0022065 seed weevil Comment: Most effective agent. Little need for Method: Aspirate Comment: Has been mostly redistribution. Look for shot holes in older leaves. Attack rate: Heavy displaced by other agents. Produces hard gall. Exapion fuscirostre Stage: Adult Comment: Collect when plants are 2-4 Control: Good inches. Best in Eastern Oregon. Yellow starthistle seed head weevil Year: 1983 Collectability: Mass Eustenopus villosus YELLOW TOADFLAX Distribution: Widespread Release No. 100 Attack rate: Heavy Tyria jacobaeae Canada thistle gall fly Timing: Mar and Jul Year: 1990 Distribution: Widespread Linaria vulgaris Control: Good Urophora cardui Method: Sweep net/racquet Attack rate: Heavy Control: Excellent Year: 1960 Stage: Adult Collectability: Mass Release No. 100 Yellow toadflax Collectability: Mass Distribution: Year: 1980 Release No. 100 Comment: Found on musk, Italian, and slenderflower Timing: Jun–Jul Method: Sweep net stem weevil Widespread Distribution: Widespread thistles. May attack native thistles.Aspirate in spring Stage: Adult Comment: Best at 5–10% bloom. Timing: Apr–May Method: Beating sheet Mecinus janthinus Attack rate: Heavy Attack rate: Heavy on rosettes on musk thistle. Most effective agent. Stage: Adult Comment: Aspirate from beating Control: Excellent Control: Fair sheet. May be displaced by seed beetle. Year: 2011 Collectability: Collectability: Mass Distribution: Limited Mass Release No. 50 Attack rate: Heavy Release No. Timing: Oct–Nov Control: Excellent 250–500 Method: Harvest Stage: Pupa Collectability: Limited Timing: Jun–Jul Comment: Collect galls after Release No. 100 Timing: May–Jun Method: Handpick Stage: Larva killing frost, scatter widely at site. Method: Sweep net Stage: Adult Comment: Best at large infestations. Stunts plants, reduces flowering. Comment: Emerging success. Specific to yellow Not recommended for Eastern Oregon. toadflax.