Treesearch

The goldspotted oak borer (GSOB) Agrilus auroguttatus (Coleoptera: Buprestidae), has killed over 80,000 oaks across all land ownerships, costing over $8 million in public and private funds for mitigation and response. Linked to oak mortality in San Diego County in 2008, this exotic beetle likely arrived in California through infested firewood from Arizona and attacks three native oak species found through California and southern Oregon: coast live oak (Quercus agrifolia), California black oak (Q. kelloggi), and canyon live oak (Q. chrysolepis). The University of California Division of...

In 2012, the goldspotted oak borer (Agrilus auroguttatus, GSOB) was discovered in the mountain community of Idyllwild, 56.3 km north of its known area of infestation. This was the third time that a point of outbreak was discovered >32.2 km from the GSOB infestation area, suggesting that human transport of GSOB has substantially expanded the halo of California communities at imminent risk of GSOB-associated oak mortality. Even though this pattern of dispersal puts more communities at risk, the isolated nature of these new points of infestation offer some hope that their damage could be...

We counted seedlings and assessed crown characteristics and abundance of fire-induced stump sprout regeneration in California black oak (Quercus kelloggii) 11 to 12 years after wildfire. Regeneration was examined across three levels of burn severity (low, moderate, and high) according to the Composite Burn Index. Fire severity affected crown width of oak sprout clumps; clumps of a given width were taller in areas of high severity fire. Multi-stemmed, sprouting black oak genets were more common than black oak seedlings. The data illustrate a positive sprout clump density association with...

The goldspotted oak borer, Agrilus auroguttatus (Coleoptera: Buprestidae), was first associated with oak mortality in San Diego County, California in May of 2008. Since that time, a research and survey program has outlined the biology of this flatheaded borer in the invaded and native habitats; delimited the invaded range; and developed the components of an integrated pest management (IPM) program. Significant advances have been made in the understanding of its host range, feeding habits, life cycle, and natural enemies in Arizona and California. Some research progress has also been made...

The earliest signs of goldspotted oak borer (Agrilus auroguttatus, GSOB)-associated oak declines can be found in 1996 aerial photo images from the Descanso area of San Diego County. By 2014, GSOB had spread over a 4000 km2 area, with a patchy distribution similar to the early spread of the emerald ash borer (Agrilus planipennis). The GSOB occurs over about 26,250 ha (60 percent) of the oak woodlands in its primary range of infestation; with heaviest damage near rural housing and communities. Three GSOB diaspora have occurred 30, 40, and 55 km from closest known infestation areas, implicatin...

Goldspotted oak borer, Agrilus auroguttatus, has killed approximately 27,000 mature oaks in southern California. Consequently, the future spread of this insect is a significant concern to many oak woodland managers in California and across the United States. "Risk" reflects the likelihood that A. auroguttatus will continue to spread in North America and the magnitude of ecological, economic, or social impacts that this insect may cause. This research project measured several critical biological parameters to refine spatial risk assessments for this insect. Cold tolerance testing of...

California’s oak woodlands are threatened by the recent introduction of goldspotted oak borer (Agrilus auroguttatus). This invasive wood-borer is indigenous to mountain ranges in southern Arizona where its low population densities may be due to the presence of co-evolved, host-specific natural enemies. Reuniting A. auroguttatus with these natural enemies can potentially provide permanent control of this pest. To initiate a classical biological control program, our research focused on investigating the genetic variation within and between populations in the native and introduced ranges in...

The exotic goldspotted oak borer (GSOB), Agrilus auroguttatus (Coleoptera: Buprestidae), continues to cause elevated oak mortality in southern California. Initial GSOB research was directed at developing an integrated pest management program. However, little research has examined the secondary impacts associated with this invasive pest. My primary objective was to compare the fuel loading in severely GSOB-infested woodlands (>10 years of oak mortality) to uninfested woodlands in southern California. Forest stand characteristics, canopy fuels, understory fuels, and surface fuels were...

Private land plays a crucial role in the conservation of biodiversity in California, yet these lands are the least protected and most prone to environmental degradation. In 1930, Aldo Leopold recognized the potential to better conserve private land by an incentive scheme where recreational users would pay landowners for access to conserved wildlife habitat. While research has shown that significant funds are spent to utilize large areas of private land for wildlife-associated recreation, this study seeks to specifically understand whether this recreational use actually results in improved...

Oak acorns have historically provided food for humans and animals in cultures across Asia, North Africa, Europe, and North America. The advent of the twentieth-century saw acorns become marginalized as a food crop in the United States and most of the world, but they have remained a constant part of the cuisine of the Korean Peninsula. Consequently, Korea is often cited when discussing the potential of a commercial acorn industry in California, yet little is actually known about acorn production in Korea. This is a report of preliminary results from a project conducting interviews across...