Research Interests:
Research Interests:
Research Interests:
Research Interests:
Over the past decade, the University of California Statewide IPM Project has been extending pest management information electronically to farmers, pest management consultants, landscapers, and home gardeners. During this session we will... more
Over the past decade, the University of California Statewide IPM Project has been extending pest management information electronically to farmers, pest management consultants, landscapers, and home gardeners. During this session we will demonstrate the Project's web site (http://www.ipm.ucdavis.edu) and a CD-ROM developed to assist horticulture advisors, Master Gardeners, retail nursery personnel, and others who help gardeners manage pest problems. We will discuss considerations in using these programs for extending information, keeping the programs up-to-date, and integrating them into educational programs. The CD-ROM covers 40 vegetables and tree fruits, allowing users to specify visual symptoms, describe a situation, or look at color photos, video images, or line drawings to help identify the problem. Twenty-five to 35 different pests are included for each crop, with thousands of photo images. An ornamentals module will be added in 1998. Once the problem is identified, the sy...
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
The walnut twig beetle (WTB), Pityophthorus juglandis, is associated with thousand cankers disease of walnut (Juglans sp.). Spores of the pathogenic fungus, Geosmithia morbida, are introduced into the phloem when the beetles bore through... more
The walnut twig beetle (WTB), Pityophthorus juglandis, is associated with thousand cankers disease of walnut (Juglans sp.). Spores of the pathogenic fungus, Geosmithia morbida, are introduced into the phloem when the beetles bore through the bark. The infection results in numerous cankers that eventually kill the tree. The WTB is expanding its range and causing increased tree mortality in the western U.S. Little is known about the semiochemicals that mediate the colonization of host trees by WTB. Trees are initially colonized by male WTB, which then release pheromones attractive to both sexes. Arriving females also contribute to the aggregation pheromone. We collected volatiles on Porapak Q from male or female WTB feeding on J. hindsii branches, and from the branches alone. Pentane extracts of the Porapak were analyzed by GC-MS. Four compounds identified in the extracts from males feeding on J. hindsii were not present in extracts from females. Two other compounds of interest were f...
The goldspotted oak borer (GSOB), Agrilus coxalis, (Coleoptera: Buprestidae) is non-native to California and has recently been linked with oak mortality occurring in southern California since 2002. GSOB injures and kills coast live oak... more
The goldspotted oak borer (GSOB), Agrilus coxalis, (Coleoptera: Buprestidae) is non-native to California and has recently been linked with oak mortality occurring in southern California since 2002. GSOB injures and kills coast live oak (Quercus agrifolia), California black oak (Q. kelloggii), and canyon live oak (Q. chrysolepis), across all land ownerships. Oak mortality is impacting landscape aesthetics, property values, increasing health hazards around dwellings, and changing the fuel structure in areas prone to wildfire. To improve survey and detection of GSOB in California, we are: 1) Determining the adult flight period with purple and lime green prism flight-intercept sticky panel traps; 2) Determining the most effective height (1.5, 3, and 4.6 m) for purple and lime green prism traps; and 3) assessing volatiles [(Z)-3-hexenol, Manuca oil, and Phoebe oil] as lures for enhancing adult trap catch.
Thousand cankers disease (TCD), which affects walnut trees, has contributed to walnut mortality in the western United States for over a decade. It is caused by the bi-phasic fungus, Geosmithia morbida, and is vectored by the walnut twig... more
Thousand cankers disease (TCD), which affects walnut trees, has contributed to walnut mortality in the western United States for over a decade. It is caused by the bi-phasic fungus, Geosmithia morbida, and is vectored by the walnut twig beetle (WTB) Pityophthorus juglandis. Although the beetle is native to California, it was not considered a pest until recently, when G. morbida was identified as the causal agent of the deterioration of walnut tree health in California (2008). The interaction between WTB and G. morbida has not yet been fully characterized. Annual walnut tree (Juglans) surveys were conducted at six sites in California (Butte, Los Angeles, Solano, Sutter, Tulare, and Yolo Cos.) for symptoms of WTB and TCD (2009-2011). Sites were chosen to represent various species of Juglans and a range of environments (orchard, urban, and wildland). Geosmithia morbida propagule loads were measured from WTBs collected in funnel traps in each of the six survey sites (2011). Future annua...
Walnut twig beetles (WTB), Pityophthorus juglandis, are native to New Mexico, Arizona, California, and Mexico. Recent surveys have documented that WTB populations have spread to Tennessee (2010), Virginia (2011), and Pennsylvania (2011),... more
Walnut twig beetles (WTB), Pityophthorus juglandis, are native to New Mexico, Arizona, California, and Mexico. Recent surveys have documented that WTB populations have spread to Tennessee (2010), Virginia (2011), and Pennsylvania (2011), states where eastern black walnut, Juglans nigra, is a major timber species. The impact of WTB on walnut has recently become accentuated by its association with a potent fungal pathogen, Geosmithia morbida. Eastern black walnut is particularly susceptible to G. morbida. WTB carry G. morbida spores and, during gallery construction, they deposit them in the phloem of branches and stems of walnut trees. These conidia germinate and the fungus colonizes the phloem. This weakens and can ultimately kill the tree. The disease condition (thousand cankers disease) has been known to kill a healthy tree in 1-3 years. Previous research has shown that male WTB colonize branches first, produce an aggregation pheromone, and the flight response of both sexes increas...
Thousand cankers disease of walnuts, caused by the fungal pathogen, Geosmithia morbida, has led to the decline and death of native and introduced walnut trees, Juglans spp., throughout the USA. The pathogen is vectored as conidia by the... more
Thousand cankers disease of walnuts, caused by the fungal pathogen, Geosmithia morbida, has led to the decline and death of native and introduced walnut trees, Juglans spp., throughout the USA. The pathogen is vectored as conidia by the walnut twig beetle (WTB), Pityophthorus juglandis, as it bores through the bark and enters the phloem. We trapped both sexes of adult WTB with aggregation pheromone-baited Lindgren funnel traps and developed a real-time quantitative polymerase chain reaction assay (TaqMan Procedure) to calculate the number of G. morbida spores on individual beetles.To do this we compared quantification cycle (Cq) values of our samples to Cq values of a plasmid reference curve (pCR2.1, Eurofins Genomics, Huntsville, AL). Identification and quantification of G. morbida was based on species-specific primers and hydrolysis probes from the β-tubulin gene. Beetles were collected during May/June and August (2012-2014) at six study sites in California (Butte, Los Angeles, So...
Research Interests:
Research Interests: Zoology and Life history
Monitoring is the systematic collection and re- cording of information on pests and damage. Scale insects and aphids, respectively, can be efficiently monitored using sticky tape traps and water sensitive paper. We describe these... more
Monitoring is the systematic collection and re- cording of information on pests and damage. Scale insects and aphids, respectively, can be efficiently monitored using sticky tape traps and water sensitive paper. We describe these monitoring techniques, present examples of their use in con- trolling citricola scale infesting Chinese hackberry and painted maple aphid infesting silver maple, and discuss our methods
Research Interests:
Research Interests:
The straw itch mite, Pyemotes tritici Lagrèze-Fossat and Montané (Acari: Pyemotidae), was discovered parasitising the goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), an invasive exotic species to... more
The straw itch mite, Pyemotes tritici Lagrèze-Fossat and Montané (Acari: Pyemotidae), was discovered parasitising the goldspotted oak borer, Agrilus auroguttatus Schaeffer (Coleoptera: Buprestidae), an invasive exotic species to California, United States of America, and the Mexican goldspotted oak borer, Agrilus coxalis Waterhouse (Coleoptera: Buprestidae), during surveys for natural enemies for a classical biological control programme for A. auroguttatus. Pyemotes tritici caused low levels of mortality to each species of flatheaded borer, but it will likely not be a good candidate for a biological control programme because it is a generalist parasitoid with deleterious human health effects.
Research Interests:
Research Interests:
Research Interests:
The invasive goldspotted oak borer, Agrilus auroguttatus, is threatening the health and survival of oak trees in San Diego County, California. From two sites in the core area of the infestation, we report a 2.5 year investigation of the... more
The invasive goldspotted oak borer, Agrilus auroguttatus, is threatening the health and survival of oak trees in San Diego County, California. From two sites in the core area of the infestation, we report a 2.5 year investigation of the impact of A. auroguttatus on coast live oak, Quercus agrifolia, before and after treatment with two systemic insecticides, emamectin benzoate (EB) and imidacloprid (IC). None of the 446 survey trees died during the study. The crown dieback rating of most trees at both study sites remained unchanged, regardless of insecticide treatment. A higher cumulative increase in the number of A. auroguttatus emergence holes was observed on trees that were previously infested and on trees with larger diameters. Over the 2.5 year period, the new infestation rates of initially uninfested trees across the untreated and treated groups were 50% (EB) and 32% (IC), and neither EB nor IC treatment affected cumulative increases in the number of emergence holes. EB-injecte...
Research Interests:
Moderate to large scale California growers (as well as small scale ones) manipulate cropping patterns in a number of ways to reduce pest problems. Crop rotation, which can be defined as diversifying crops over time, is used to manage... more
Moderate to large scale California growers (as well as small scale ones) manipulate cropping patterns in a number of ways to reduce pest problems. Crop rotation, which can be defined as diversifying crops over time, is used to manage selected pests, primarily weeds, pathogens, and nematodes. As a substitute for pesticides, crop rotation has been most rewarding in the control of nematodes; sugarbeet cyst and root knot nematode examples are detailed. Some pests that invade fields from nearby areas can be managed by modifying adjacent cropping patterns or practices; Pierce's disease of grapes, sugarbeet yellows and border harvesting of alfalfa are given as examples. Finally, multiple crops can be grown within a single field or orchard. Although this approach is not widely practiced by many California growers, two examples of systems where intercropping has been shown to limit pest numbers without the use of pesticides are described: intercropping of cotton with alfalfa and companio...
Research Interests:
Research Interests:
Research Interests: Reproduction, Invasive Species, Climate, California, Plant diseases, and 15 moreSex ratio, Animals, Canary Islands, North America, Beetles, Bark Beetle, Pinus, Economic Entomology, Mediterranean region, North American, Scots Pine, Host Range, Loblolly Pine, Ecological Applications, and Current Distribution
Research Interests:
Deguang Liu, dgliu@ucdavis.edu 1 , Robert C. Venette, rvenette@fs.fed.us 2 , Steve Munson, smunson@fs.fed.us, Beverly Bulaon, bbulaon@fs.fed.us 3 , Mary Louise Flint, mlflint@ucdavis. edu 4 , and Steven J Seybold, sseybold@fs.fed.us 5 .... more
Deguang Liu, dgliu@ucdavis.edu 1 , Robert C. Venette, rvenette@fs.fed.us 2 , Steve Munson, smunson@fs.fed.us, Beverly Bulaon, bbulaon@fs.fed.us 3 , Mary Louise Flint, mlflint@ucdavis. edu 4 , and Steven J Seybold, sseybold@fs.fed.us 5 . (1) University of California, Davis ...