1995UC IPM Advisors
Regional IPM advisors are located at the UC Kearney Agricultural Center at Parlier, with specialties in nematology (Pete Goodell), plant pathology (Jim Stapleton), entomology (Walter Bentley) and weed science (Tim Prather). Three IPM advisors with more cross-disciplinary assignments are located in other regions of the state: south coast (Phil Phillips), Sacramento Valley (Carolyn Pickel) and north coast (Lucia Varela). A new IPM advisor (Cheryl Wilen) for IPM for ornamental horticulture in the southern region was added in September 1995. Peter Goodell is IPM advisor coordinator. Summarized below are some of the key activities of the IPM advisors in 1994-95. Click on a name to quickly link to more information.
Cheryl Wilen, Southern Region/Ornamental Horticulture
Phil Phillips, South Coast
Lucia Varela, North Coast
Carolyn Pickel, Sacramento Valley
Tim Prather, Kearney Agricultural Center/Weeds
Pete Goodell, Kearney Agricultural Center/Extension Coordinator
Walt Bentley, Kearney Agricultural Center/Entomology
Jim Stapleton, Kearney Agricultural Center/Plant Pathology
A new IPM advisor, Cheryl Wilen, joined the UC IPM Project staff in September 1995. The focus of her position is integrated pest management for ornamental horticulture including greenhouse, nursery and landscape situations. Cheryl's training has focused strongly in weed science and horticulture; she has a Ph.D. in Botany from UC Riverside and a M.S. degree in Horticulture from the University of Arizona. However, her responsibilities at the IPM Project will include the management of all types of pests attacking ornamental plants. The position is headquartered in the San Diego UC Cooperative Extension office but also serves Orange and Los Angeles counties.
Cheryl Wilen, South Coast
Development of IPM programs in a variety of fruit and vegetable crops has been the focus of Phil Phillips' activities over the last year. In avocados, Phil has been helping to coordinate the establishment of biological control agents for a newly established mite pest, the persea mite, as well as develop additional biological information about the pest itself. Predator release rate trials and miticide trials have been conducted.
In celery, using a Septoria leaf blight forecasting model, Phil has successfully reduced fungicide use with field demonstrations in cooperation with Campbell Soup. In strawberries, demonstration plots on early versus late release of predatory mites and on impact of pesticides on predatory mites have been a major activity.
Phil has several projects in citrus. For several years he has been developing information on the impact of groundcovers on nematodes, snails, gophers and arthropod pests and beneficials. He is also looking at ant management in citrus. Phil has spent several years investigating the potential of a new environmentally benign approach using a chemical ant repellant, farnesol. He is currently assisting with ant bait formulations and bait acceptance trials to prevent honeydew foraging ants from disrupting biological controls.
Dust can also disrupt biological control programs. Phil is investigating the effects of ambient dust accumulation over the season on direct mortality in key insectary-reared parasitoids. One project involves PM-10 dust monitors within citrus orchards adjacent to a proposed mining project.
In grapes, Phil has been helping to establish biological control agents for a recently arrived pest, the obscure mealybug. Pesticide timing trials and detailed phenological studies are also part of the overall mealybug management trials. Phil's recent work with yellow sticky tape for leafhopper control has shifted to investigating the possibilities of intercepting vectors of Pierce's disease, such as blue-green and red-headed sharpshooters, using this same sticky tape technology.
Phil A. Phillips, South Coast
Four Wine Grape Pest and Benefical Insects Identification workshops were offered by Lucia in collaboration with Dr. Rachid Hanna in the North Coast. Participants who included growers, PCAs and farmworkers, learned to distinguish between the two spider mites injurious to grapes and the predatory mite controlling them and how to identify leafhooper eggs parasitized by the tiny wasp Anagrus. It is important to be able to distinguish between Willamette and Pacific spider mites because the biology, damage and treatment thresholds for these two pests are different. Treatment thresholds are based on spider mite as well as predatory mite counts so accurate identification is crucial in order to reduce or possibly eliminate miticide applications. The workshop was a "hands-on" interactive training in which each participant had a microscope available to learn identification and hand lens for practicing the skills learned.
Grape leafhopper eggs are parasitized by a tiny wasp of the genus Anagrus. Lucia is studying the impact of the egg parasite on leafhopper populations to develop a monitoring procedure that would take into account parasitism levels in the determination of treatment thresholds. The aim is to reduce the use of pesticides targeted at the leafhopper which, if its eggs are parasitized, may not be necessary. Since grape leafhoppers overwinter in the adult stage, the parasitic wasps need an alternate host egg in which to overwinter. Anagrus wasp is reported to overwinter in the egg of the blackberry leafhopper in riparian areas and in the egg of prune leafhoppers in prune orchards. At the present time there is some confusion about the species of Anagrus attacking different leafhoppers. Lucia is collecting Anagrus from different leafhopper hosts throughout the wine region of the North Coast for identification by UC Riverside systematists.
In recent years oblique-banded leafrollers have become a problem in the North Coast pear region both in orchards under codling moth pheromone confusion and in orchards treated with conventional insecticide for codling moth control. To successfully implement codling moth mating disruption, Lucia is evaluating Bacillus thuringiensis, a less disruptive alternative, for controlling oblique-banded leafrollers. She is also conducting studies on the susceptibility of oblique-banded populations to the major insecticides used for codling moth control. If oblique-banded leafrollers have become resistant to the pesticides used for codling moth control, this may explain the recent outbreaks in conventional orchards.
Orange tortrix causes damage by feeding on grape bunches, making them vulnerable to disease infection. Through a sampling technique using trap catches and cluster infestation, and validation of orange tortrix degree-day model, Lucia is determining when and whether control measures against orange tortrix are needed. Orange tortrix natural mortality is also being evaluated to determine levels of parasitism that keep the population of orange tortrix below damage threshold.
Telemetry has recently become available to obtain weather information from the field. Lucia is monitoring codling moth phenology in the pear region and orange tortrix phenology in the grape region to validate degree-day models for these insects using weather station information through telemetry technology.
Lucia Varela, North Coast
Carolyn is coordinating several research projects in orchard crops. Her project looking at the use of Trichogramma platneri to control codling moth in walnuts is a team project involving all the walnut farm advisors in the Sacramento Valley. There are two research plots with one located centrally so all advisors can participate. This is important because substantial labor is required for release of the parasites and for data collection. Also all the farm advisors are participating in development of research and extending information. Farmers and PCAs have shown a great interest in this project.
Carolyn's walnut husk fly project is aimed at developing better trapping and spray timing for this serious pest. The project brings farm advisors and researchers together in three research plots in Corning in Tehama County, Gridley in Butte Country, and Esparto in Yolo County.
Growers are increasingly using pyrethroids both in dormant and foliar applications in prunes, almonds and cling peaches. Working with Project Director Frank Zalom and local farm advisors, Carolyn has established plots to find out the efficacy of dormant and in-season sprays of pyrethroid materials on peach twig borer, oriental fruit moth and navel orangeworm and their effects on predator mites and general predators. Residue analysis is being conducted by Environmental Toxicology Specialist Mike Stimman to find out how long the materials remain effective on the bark of the tree. This research is directed at answering questions farm advisors have been asking for several years.
In the summer of 1995, Carolyn coordinated seven "hands-on" field meetings with farm advisors in the Sacramento Valley. Clientele attending the meetings were given current pest updates, participated in monitoring and sampling demonstrations, and had the opportunity to review the natural enemy teaching collection. They were taught how to use hand lenses and were sent out into the orchard to try out the sampling techniques. Growers learned to identify European red mite, twospotted mite and predator mites both as adults and eggs. Growers were excited about being able to identify pests, natural enemies and damage they commonly see in their orchards. For instance, leafhopper excrement had puzzled some for years!
Cooperating with farm advisors Bill Olson and Janine Hasey, Carolyn continued her mating disruption demonstration program on cling peaches. Nineteen growers participated in Sutter, Yuba, and Butte Counties. The project demonstrated the use of both oriental fruit moth and peach twig borer pheromone disruption in an effort to expand the use of this technique; this was the first year the peach twig borer pheromone became commercially available. All participating growers have kept records on the cost of application; these costs will be compared to a grower standard to give an economic evaluation of pheromone disruption programs.
Carolyn also holds a comprehensive IPM winter workshop for growers and PCAs in cooperation with local farm advisors. This year's meeting was for cling peach growers. She has also particpated in the Prune Mini Short Course conducting hands-on field meetings on prune aphids and mite sampling.
Carolyn Pickel, Sacramento Valley
Tim Prather, the Project's IPM advisor with a vegetation management specialization, is involved in a variety of projects focused on better weed management. 1994-95 was his second year of work using light-activated sprayers to control weeds in orchard crops; this year he began to use the equipment in row crops as well. Tim has been calculating the savings in herbicide costs to growers when using the equipment at low to high weed populations. Savings are greatest when weeds cover less than 20% of the ground surface. The older model of the equipment from the manufacturer was capable of reducing the amount of herbicide applied by 70% when weeds occupied 5% of the ground surface.
Another project is investigating deep plowing for control of yellow nutsedge, purple nutsedge and annual morning-glory. Yellow nutsedge appears to be controlled better than the other two but additional work will be needed to determine the effectiveness of deep plowing for control of purple nutsedge and annual morning-glory. Plowing using a modified moldboard plow called the Kverneland plow, inverted the soil profile, taking yellow nutsedge tubers that were near the soil surface and burying them to the plow depth (10 to 16 inches). There were 80% fewer plants on the bed top, contrasted to a standard moldboard plow. Emergence of plants from tubers was delayed by about four weeks where the Kverneland plow was used.
Identification of pests is an important part of an IPM program and Tim is working on a computer program to identify weed seedlings. Also in the works is a manual that will detail the seed and several seedling stages and features the photography of Jack Clark. Working with Tim on the project are Robert Norris and Clyde Elmore at UC Davis.
California's pesticide use reporting system has opened doors to new research and education opportunities. Tim has been working with Jodie Holt on a herbicide resistance project that uses CalTrans pesticide records to find locations where sulfonylurea herbicides have been used repeatedly. This class of herbicides has a history of selection for resistance. Jodie and Tim have found Russian thistle plants that were resistant. The project continues this year with expanded sampling of areas that have received 0 to 4 yearly applications and will include prickly lettuce and Russian thistle. Both prickly lettuce and Russian thistle have sulfonylurea-resistant populations in other parts of the U.S.
Tim and Jodie are starting work on another project that will develop degree day phenology models for weeds. This project is well timed given the increased emphasis, in California, on post-emergent control of weeds. Tim and Jodie envision using these models to determine groups of species that emerge at similar times so that the groups can be controlled together with one cultivation or herbicide application rather than multiple controls.
Tim is recording the economics of weed control in iceberg lettuce in the Salinas Valley. Several rates of the herbicide Kerb are used for initial weed control. Thinning and hand weeding costs are then recorded for each treatment. The overall economic profitability of a specific herbicide rate will be dependent on the species and density of weeds present. In fields without a recent history of serious weed problems, a lower rate could be used and achieve the same level of control without adding seeds to the seed bank.
Tim is working on a project coordinated by Specialist Tom Lanini that uses a variable rate of Treflan at layby in tomatoes. The highest rate is used over the furrow with decreasing amounts next to the crop row. The idea is to allow plant competition from the tomatoes to control most weeds next to the crop and reduce the use of herbicides. Also working on the project with Tom are Michelle LeStrange, Kurt Hembree, Gene Miyao and Brian Correiar.
Tim has worked with on the Orchard Odyssey, a peach and nectarine demonstration project at Kearney Agricultural Center led by Pomology Specialist Scott Johnson. Tim is working on weed control options. This year the Orchard Odyssey was visited by school children from a number of surrounding school districts. Approximately 500 students visited the site over a several day period. The students were able to have hands-on experiences on all aspects of peach and nectarine production. Tim had a number of demonstrations for the kids that included cloning, a light-activated sprayer, mulches and weeds that plant themselves.
Tim Prather, South Central Region
Developing and delivering IPM information about row and field crops in the South-Central region continues to be the focus of Pete Goodell's program. Pete continues to work closely with cotton farm advisors, PCAs, and producers to improve cotton pest management. Outreach techniques include articles in farm advisors' newsletters, winter workshops, and summer production meetings, contacting over 1,000 people. Pete is maintaining the whitefly mailing list server as well as updating a toll free hotline focused on cotton insects. His receipt of a Smith-Lever 3(d) IPM extension grant allowed a limited number of cotton fields to be closely monitored and a baseline of insect activity developed across a broad area. The information obtained provides useful case studies when discussing current pest management problems.
Pete has invested considerable time in developing community-based programs. These revolve around field and vegetable crops in the west side of Fresno County and include farmers, PCAs, government agencies, allied agricultural industries, and commodity boards. The San Joaquin Valley Whitefly Management Group and the San Joaquin Valley Virus Task Force are two examples.
Pete's research program has been primarily directed toward two pests, lygus bugs and root knot nematode. As a response to a request from the California Bean Advisory Board, he has begun to work on the impact of lygus feeding on the quality and quality of cowpeas. This work is directed at the importance of feeding at various times during the production cycle. His work with root knot nematode on cotton has demonstrated the management approaches to this pest in the absence of fumigants. Using rotations and incorporating resistant Acala varieties has allowed cotton to be produced while reducing the overall population of this pest. This strategy has positive effects on subsequent crops such as carrots, potatoes, lettuce, tomatoes and melons.
Pete has continued to represent California IPM at a national level through his participation in the Extension Committee on Policy's IPM Task Force and as one of the IPM Coordinators for California.
Peter B. Goodell, Coordinator
During 1995, Walt's first year with the IPM Project, his entomological research and educational projects were aimed at reducing the use of synthetic, broad spectrum pesticide use in crops such as almonds, walnuts, pistachios, peaches, nectarines, apples, prunes and grapes.
This work has involved implementing mating disruption programs for pests such as codling moth, peach twig borer, and oriental fruit moth. These projects were done in cooperation with farm advisors Mario Viveros and Kathy Kelley using commercial farmers' orchards in side by side comparisons with traditional insecticide treated orchards. For crops such as peaches and almonds, mating disruption, although more costly than commonly used insecticides, has resulted in a reduction of insecticide sprays with no increase in fruit damage. The results for codling moth in apples, although not as successful, have shown great potential in newly planted orchards where codling moth populations can be kept at low levels. The work in apples was part of a cooperative project with Sean Swezey at UC Santa Cruz, and farm advisors Janet Caprile and Paul Vossen.
Complementing the efforts to reduce use of broad spectrum pesticides with mating disruption has been the investigation of the role of dormant sprays with synthetic insecticides, particularly the pyrethroids, in contributing to spidermite abundance during the growing season. Walt is part of a team, along with IPM advisor Carolyn Pickel and specialists Frank Zalom and Michael Stimman, looking at the stimulatory impact of pyrethroids on webspining spidermite abundance. The lower cost of pyrethroids have made them more attractive than BT sprays for peach twig borer. Many growers have been moving towards use of them for that reason. This work will show if there are negative side effects of sprays which result in greater pesticide use during the growing season.
In nectarines, where western flower thrips is a key pest problem requiring repeated insecticide applications, colored sticky traps were hung on trees during the susceptible bloom and petal fall period in attempts to attract thrips from blossoms to sticky traps. This would reduce damage done by these insects to nectarines. Due to late spring rains, little thrips damage was recorded on the control trees which received no treatment. This study will be continued in the future.
A major project initiated during 1995 was the evaluation of various nondisruptive bait formulations for ant control in crops such as almonds, and grapes. This work is in collaboration with entomologists Harry Shorey, Elizabeth Grafton-Cardwell, Phil Phillips and Richard Coviello. Ants studied were the southern fire ant, pavement ant, argentine ant, and the native gray ant. In grapes some of these species will tend pests such as grape mealybug and lecanium scale, feeding on the honeydew they exude. In exchange for this food they protect the mealybugs and scale from natural enemies which can provide control of the pests. In almonds the southern fire ant and pavement ant do primary damage by feeding on the nuts while on the ground. In both these cases disruptive sprays are widely applied for ant control but are not adequately controlling populations. Baits can be used more effectively, selectively and with much less active ingredient.
A series of three pistachio pest management programs were accomplished in the spring of 1995. Meetings were held in Durham, Madera and Bakersfield in conjunction with the Pistachio Commission and the local UC Cooperative Extension offices. The recently published fact sheets on insects and disease problems in pistachio were provided by the Commission and given to the attendees. Insect and disease specimens were shown to participants and the management techniques for them presented. Sampling methods were also demonstrated to the participants, and participants reviewed the current Pistachio Pest Management Guidelines.
Walt serves on the management team for the almond BIOS project and has been very active in the insect and mite pest management aspect. He has participated in educational programs, publications, research projects and is now focusing on developing data from participating growers.
Walter Bentley, South Central Region
Jim's program responsibility is centered on development and implementation of IPM strategies for management of plant diseases and disease complexes. He is in the midst of a three-year project to evaluate biodegradable, reflective spray mulches for control of plant viruses and their aphid vectors in vegetable crops. The complex of virus diseases has caused major economic losses in several susceptible crops in the San Joaquin Valley during recent years. Working in collaboration with UCD entomologist Charles Summers, also based at Kearney, Jim's laboratory has been testing the effects of wavelength-selective spray mulches on health and production of eggplant, melons, pepper, squash and tomato. Also, the mulch techniques are being integrated with other methods of repelling aphids such as alarm pheromones and plant "whitewashes." The results continue to be excellent, and significant producer interest has been generated in this innovative cultural aid.
Jim also continues to devote a considerable portion of his research and extension time and effort to integrated management of diseases of wine and table grapes, with an emphasis on bunch rots. Jim served as disease section coordinator for the 1995 Pest Management for Grapes Workshop sponsored by UC/IPM at Kearney, and co-instructor of the disease section of the course to over 100 participants. In addition, Jim continues collaborative projects to evaluate the biological and economic pros and cons of fungicide sprays to control bunch rots in the San Joaquin Valley. Results continue to show that bloom-time sprays may be of value in cooler, more humid growing areas more conducive to Botrytis bunch rot, or after exceptionally wet rainy seasons, such as occurred in 1994-95. Other projects, primarily in table grapes, aim at clarifying the epidemiology of the "summer bunch rot complex" including fungal, bacterial, and insect pest components.
With the impending loss of methyl bromide as a soil fumigant, soil solarization is gaining momentum as an alternative soil disinfestation method for use with shallow-rooted crops and containerized nursery production in the hot, interior valleys of California. Jim is providing treatment guidelines to growers who wish to test and use solarization, and he continues to work on integrating solarization with organic soil amendments that give off toxic volatile compounds to provide a more effective form of "biofumigation." Jim and UCD Extension Pomologist Louise Ferguson (also based at Kearney) are evaluating solarization of containerized planting media for nursery production, and will soon have guidelines ready for dissemination to farm advisors and producers.
Jim continues to edit and produce the Plant Protection Quarterly, a newsletter reporting UC pest management research and educational activities in California.
James Stapleton, South Central Region