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 insects (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 Animal 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 moth 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 Centaurea 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 Centaurea stoebe = 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: Larva/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 fly of infested plants. All female Control: Good under rosettes. Disperse upon release. parasitized. species. May become available Collectability: Limited Urophora affinis soon. ODA biocontrol projects Release No. 50–100 Year: 1975 Timing: July Knapweed root beetle 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 Larinus 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