EAB Biological Control and Parasitoid Recovery in Minnesota Christopher Mallet, Monika Chandler, Jonathan Osthus, and Angie Ambourn, Minnesota Department of Agriculture. Brian Aukema and Rob Venette, University of Minnesota St. Paul. 10/14/2018 Outline Biocontrol Status Recovery Methods • Yellow Pan Trapping • Bark Sampling • Branch Sampling Recoveries in MN Research from MI Status Update • Biological control of emerald ash borer (Agrilus planipennis) (EAB) was initiated in Minnesota in 2010. Year Spathius galinae Tetrastichus planipennisi Oobius agrili Spathius agrili Total per year 2010 0 2154 0 1172 3326 2011 0 19480 3641 7596 30717 2012 0 19822 10241 15258 45321 2013 0 42579 8597 0 51176 2014 0 34434 12062 0 46496 2015 0 151022 31490 0 182512 2016 1613 45130 42300 0 89043 2017 2151 43245 23100 0 68496 2018 4636 27310 12600 0 44546 Total 8,400 385,176 144,031 24,026 561,633 The parasitoids were produced and supplied by the USDA EAB Parasitoid Rearing Facility in Brighton, MI. Current Parasitoids • Oobius agrili • Egg parasitoid • Tetrastichus planipennisi • Larval endoparasitoid • Spathius galinae • Larval ectoparasitoid Biocontrol Release Locations in Minnesota Optional Tagline Goes Here | mn.gov/websiteurl Recovery Methods Yellow Pan Traps Yellow Pan Traps • Yellow plastic bowls are affixed to stems of living ash trees. • Bowls are filled with a 20 % solution of clear propylene glycol. Insects are attracted to the yellow color and become trapped in the solution. • Samples are collected weekly June through September by pouring the contents through a paint filter. • Samples are frozen and screened under a scope. Yellow Pan Traps • First recovery of tetrastichus in the metro area at Fort Snelling State Park. 870 samples collected in 2016. 5 tetrastichus from 3 traps. • Detections of a native parasitoid Atanycolus simplex Cresson David Cappaert,Bugwood.org • 107 yellow pan traps placed at 4 locations in 2018. Sample contents under scope About 1500 samples were collected and are being screened. Bark Sampling Bark Sampling • Collect outer bark of the ash trees to collect EAB eggs and search for eggs parasitized by oobius agrili. • Measure 10 x 50cm area on trunk. Shear off with draw knife. • Bark is collected in a paper bag and allowed to dry completely (about 2 weeks) • Dried material is sieved using USDA Standard Testing Sieve No. 14 with 1.40mm openings for 2 mins. • Sifted debris, about 5 to 15 grams, is placed in a thin layer on a ceramic dish and viewed under a dissecting scope Bark Sampling • Healthy EAB eggs • Eggs filled with frass after larva emerges • Not all eggs remain intact Sifted bark debris with egg under dissecting scope Bark Sampling – Parasitized Eggs Oobius exit hole EAB eggs tend to turn dark Parasitoid meconium (larval Oobius present in egg after parasitism. waste) present in egg Bark Sampling • First recovery of oobius agrili in 2014/2015 winter at Great River Bluffs State Park. • 121 samples collected in the 2017/2018 winter among 11 sites resulting in 4 new established locations. Number of EAB Eggs Number of Parasitized Site Latitude Longitude Recovered Eggs 44.909166 -93.193194 23 1 Hidden Falls 44.986989 -93.114122 69 1 Wheelock Parkway 44.914340 -93.135757 93 1 Shepard Road 44.039037 -91.653745 22 3 Lake Winona J. Osthus, MDA Branch Sampling Branch Sampling • Whole trees are felled or branch samples are taken from the mid to upper canopy. • Bark is removed with a draw knife and EAB larvae and galleries are inspected for signs of parasitism. • Late instar EAB larvae are collected dissected to determine if parasitoids are present Branch Sampling • Clutches of tetrastichus planipennisi overwintering pupae or adults that failed to emerge can be found in EAB galleries. • First recovery of parasitoids (t. planipennisi) at Great River Bluffs State Park in fall of 2013 • Currently conducting branch sampling in areas of known establishment to try and determine impact on EAB Recoveries • 58 recoveries of released parasitoid species • 16 oobius • 42 tetrastichus • Multiple detections of native parasitoid Atanycolus spp. where yellow pan traps are deployed. Recoveries in the Twin Cities • Tetrastichus, Oobius, Atanycolus (native parasiotoid) recovered at Fort Snelling State Park through yellow pan trapping, bark sampling and branch sampling. • Oobius recovered at Hidden Falls Park, Shepard Road, and Wheelock Parkway through bark sampling in the winter of 2017/2018. Recoveries • Tetrastichus and Oobius recovered at Great River Bluffs State Park through branch sampling and bark sampling since 2013. • Oobius recovered from Lake Winona by bark sampling in 2017. • Tetrastichus recovered 4 miles away from Great River Bluffs release site by DNR ground-truthing dead ash trees after an aerial survey in 2016. Intensive Sampling • At locations with known Number of Trees Number of T. Site Latitude Longitude Number of Trees with T. planipennisi establishment of Oobius agrili Sampled planipennisi clutches 44.888060 -93.185214 and Tetrastichus planipennisi Fort Snelling 17 3 8 43.939280 -91.409170 • Branch sampling, bark Great River Bluffs 10 2 6 sampling, and yellow pan traps • Began in 2017/18 winter, Number of Bark Number of EAB Number of Percent of eggs continuing through 2019/20 Site Samples Eggs Parasitized Eggs Parasitized winter. Fort Snelling 27 111 5 4.50 28 297 7 2.36 • Hope to measure impact on Great River Bluffs EAB Research from MI Progress and challenges of protecting North American ash trees from the emerald ash borer using biological control. Duan, Jian; Bauer, Leah; van Driesche, Roy; Gould, Juli. 2018. • The suppression of EAB densities is likely to spread geographically as populations of O. agrili and T. planipennisi increase and spread to new areas, protecting the regenerating ash saplings and young trees • Over many decades, it is reasonable to assume that a diverse complex of mortality factors and lower ash density will reduce both the frequency and intensity of EAB outbreaks, permitting the growth, survival, reproduction, and conservation of Fraxinus species Thank you! http://www.mda.state.mn.us/plants/pestmanagement/eab/eabbiocontro l We acknowledge the Environment and Natural Resources Trust Fund and USDA APHIS for supplying the funding and resources for this project. Chris Mallet [email protected] 651-201-6249.