Exotic Diseases in California

By Kim Corella CAL FIRE Exotic Diseases

. Invasive Shot Hole Borer . Goldspotted Borer . Polyphagous Shot Hole Borer (PSHB)/ Kuroshio Shot Hole Borer (KSHB) PSHB KSHB . From Vietnam • From Taiwan . Attack over 303 • Attacks over 200 tree species tree species . • 15 trees species 41 tree species are reproductive are reproductive hosts hosts • Transmits 2 . Transmits 3 species of fungi species of fungi PSHB + KSHB = Invasive Shot Hole Borer (ISHB)

SHB Life Cycle and Reproduction

• Sex ratio of offspring is female biased • Brothers mate with sisters in galleries • Mated females leave the galleries to create their own galleries • Female can fly, male don’t fly, stay in the gallery • Complete life cycle in 35 days

Richard Stouthamer Lab. UC Riverside SHB Life Cycle and Reproduction

Cold tolerance – die when exposed to -5°C or -1°C Only live short time outside of gallery Don’t produce sex pheromones or aggregation pheromones. How SHB Transmits fungi

Fusarium euwallaceae (Freeman et al 2013)

Mycangia Graphium euwallaceae Figure: Matthew Kasson

Paracremonium pembeum Fungal Pathogens Transmitted by PSHB and KSHB

Polyphagous Shot Hole Borer PSHB

Euwallacea sp. 1

Kuroshio Shot Hole Borer KSHB

Euwallacea sp. 5 Shot Hole Borer Beetle complex can infest many host plants and causes branch die back and may kill host trees.

Ambrosia Beetle

Fungus (= Ambrosia)

Dead Tree dieback caused by fungal pathogens Shot Hole Borer

Vascular discoloration caused by fungi Internal Symptoms

Box Elder (Acer negundo) • Boring dust can appear like string- like projections from tree • Boring dust observed frequently at the base ISHB Reproductive Hosts

Polyphagous Shot Hole Borer

• Symptoms on Avacado Size of the plant attacked by the beetle

Avocado Coast live oak Coast Live Oak KSHB on Willow Management Options

• Avoid moving firewood • Keep trees healthy • Sterilize pruning tools • Prune infested branches • Chip < 1” and treat infested wood • Cut logs and solarize 10mil, clear, UV resistant Management Options

Chemical control – tests being conducted now Trunk sprays, systemic pesticides

Bifenthrin (Onyx) being used in urban forests Orange County – spraying trees that have no infestation or lightly infested. Best control from other insecticides tested Samples Goldspotted Oak Borer Agrilus auroguttus Goldspotted oak borer Distribution Most Susceptible

California Black Coastal Live Oak Oak Quercus agrifolia Quercus kelloggii

Less Susceptible

Canyon Live Oak Quercus chrysolpesis Life Stages of GSOB

Eggs

Mature Larvae

Adults Pupae Goldspotted Oak Borer Biology Symptoms of Infested Trees

Coast Live Oak

Black Oak Symptoms of Infested Trees

Coast Live Oak GSOB Impacts GSOB Management GSOB Management www.gsob.org

Mechanical Treatments . Grinding wood <3” . Enclose stacks of firewood with clear, 6- mil, UV resistant plastic sheeting for summer. Use aluminum screening . Debarking wood and burning or chipping bark. . Reducing firewood movement of infested material. GSOB Management Insecticides . Topical sprays - applied to main stem and larger branches >8” on high value trees . Topical preventative sprays . (Crown Rating 1-3) – Carbamate (Sevin) or Pyrethroid (Bifenthrin & Permethrin) . Systemic – trunk injection . Neonicitinoids (imidacloprid) or Emamectin benzoate . Systemic - basal spray – Dinotefuran . High levels of active ingredients in foliage samples. Foamy Bark Canker

. Fungus - sp. 41 (G. pallida) . Insect – Western oak bark beetle

Photos: Robert Sartain, Santa Clarita . Previously only detected on oak species in Europe. Foamy Bark Canker

. Decline of Coast Live Oak observed since 2012 . Monterey, Santa Barbara, Ventura, LA, Orange, and Riverside counties. Earliest detection of fungus 2009 Western Oak Bark Beetle and Fungus Association Western Oak Bark Beetle Geosmithia sp

Geosmithia sp: conidiophore Geosmithia sp: conidia Foamy Bark Canker - Symptoms Foamy Bark Canker Symptoms

. Phloem necrosis and xylem streaking WOBB Galleries

. Branch . Trunk Foamy Bark Canker

. Beetle burrows into phloem to cambium and constructs gallery against the grain.

. At one end of primary gallery female lays eggs, builds secondary gallery and dies Foamy Bark Canker

. Geosmithia sp. recovered from cankered tissue in CLO associated with WOBB. . Geosmithia sp. directly isolated from P. pubipennis and its gallery walls. . Preliminary data suggests beetle collected from FBC is a cryptic species . Drought stressed trees may be prone to attack by WOBB . Pathogenicity tests showed G. pallida is pathogenic on coast live oak seedlings and produced symptoms of foamy canker. QUESTIONS??