1995USDA-ES Smith-Lever Competitive Grants Program
Projects Summaries for 1993-94
Host status of plant species to parasitic nematodes: Development and release of a PC and MAC database.
Principal Investigators: B. B. Westerdahl, Nematology, Davis; H. Ferris, Nematology, Davis; E. P. Caswell-Chen, Nematology, Davis; R, Sloan, Nematology, Davis
Delaying the onset of strawberry powdery mildew in fruit production fields planted with inoculum-free transplants.
Principal Investigators: D. Gubler, Plant Pathology, Davis; M. Nelson, Plant Pathology, Davis; N. C. Welch, UC Cooperative Extension, Monterey and Santa Cruz Counties; R. P. Buchner, UC Cooperative Extension, Shasta-Trinity Counties
Developing a weed seed and seedling identification manual and an expert system for weed seed and seedling identification.
Principal Investigators: T. S. Prather, UC IPM Project, Kearney Agricultural Center, Parlier; C. L. Elmore, Vegetable Crops, Davis; R. F. Norris, Vegetable Crops, Davis
IPM in San Joaquin Valley cotton: Survey of arthropod fauna and clientele attitudes.
Principal Investigators: P. B Goodell, UC IPM Project, Kearney Agricultural Center, Parlier; E. E. Grafton-Cardwell, UC IPM Project, Kearney Agricultural Center, Parlier
Implementation of a post-harvest control strategy for codling moth in pears.
Principal Investigators: R. A. Van Steenwyk, Environmental Science, Policy and Management, Berkeley; W. O. Reil, UC Cooperative Extension, Yolo and Solano Counties; R. A. Duncan, UC Cooperative Extension, Sacramento County; S. C. Welter, Entomology, Berkeley
Implementation of an IPM scouting system in ornamental crops in California.
Principal Investigators: K. Robb, UC Cooperative Extension, San Diego County; J. P. Newman, UC Cooperative Extension, Santa Barbara and Ventura Counties; A. I. King, UC Cooperative Extension, San Mateo County; S. A. Tjosvold, UC Cooperative Extension, Monterey and Santa Cruz Counties
Demonstration of integrated pest management concepts for fly inspectors and other regulatory personnel.
Principal Investigator: N. C. Hinkle, Entomology, Riverside
"Hands-on" field identification of pests for growers and PCAs in the Sacramento Valley.
Principal Investigator: C. Pickel, UC IPM Project, Sutter-Yuba Counties
Co-Leaders: W. H. Olson, UC Cooperative Extension, Butte County; J. H. Connell, UC Cooperative Extension, Butte County; W. H. Kreuger, UC Cooperative Extension, Glenn County; R. P. Buchner, UC Cooperative Extension, Tehama County; J. Edstrom, UC Cooperative Extension, Colusa County; W. O. Reil, UC Cooperative Extension, Yolo County; J. K. Hasey, UC Cooperative Extension, Sutter-Yuba Counties
Implementation of a complete mating disruption program for oriental fruit moth and peach twig borer in cling peaches.
Principal Investigators: C. Pickel, UC IPM Project, Sutter-Yuba Counties; J. K. Hasey, UC Cooperative Extension, Sutter-Yuba Counties; W. H. Olson, UC Cooperative Extension, Butte County
Commercial implementation of biological control of fire blight disease of pear.
Principal Investigators: R. Elkins, UC Cooperative Extension, Lake County; S. E. Lindow, Environmental Science, Policy and Management, Berkeley
Using degree-day information to improve citrus pest management decision-making.
Principal Investigators: E. E. Grafton-Cardwell, Entomology, Riverside/Kearney Agricultural Center, Parlier; N. V. O'Connell, UC Cooperative Extension, Tulare County
Co-Leaders: M. W. Freeman, UC Cooperative Extension, Fresno County; C. E. Kallfen, UC Cooperative Extension, Kern County
Implementation and assessment of model validity and economic impact of a weather monitoring / disease risk assessment network for use in commercial grape production in California.
Principal Investigator: D. Gubler, Plant Pathology, Davis
Co-Leaders: J. F. Strand, UC IPM Project, Davis; E. A. Weber, UC Cooperative Extension, Napa County; L. J. Bettiga, UC Cooperative Extension, Monterey County; D. A. Luvisi, UC Cooperative Extension, Kern County; R. J. Smith, UC Cooperative Extension, Sonoma County; M. L. Bianchi, UC Cooperative Extension, Santa Barbara and San Luis Obispo Counties; P. A. Phillips, UC IPM Project, Santa Barbara County; L. G. Varela, UC IPM Project, Sonoma County
Reduction of antibiotic usage for fire blight control in the presence of a registered biological control agent.
Principal Investigators: R. B. Elkins, UC Cooperative Extension, Lake County; S. E. Lindow, Environmental Science, Policy and Management, UC Berkeley
Situation: Fire blight disease of pear caused by the bacterium Erwinia amylovora is one of the most important diseases of this commodity, requiring aggressive control approaches which include frequent applications of antibiotics or other bactericides. This is not only costly, but has led to the development of resistance to Streptomycin, one of the most important bactericides available for disease control. Also, the use of antibiotics in agricultural production is of concern due to the potential of plant-acquired antibiotic resistance spreading to medically important pathogens. Biological control of fire blight disease using the competitive and antibiotic-resistant bacterium Pseudomonas fluorescens A506 has been tested and demonstrated in a number of years in both small scale and large scale plots. The goal of this project is to demonstrate, on a large scale in commercial orchards, fire blight control using far fewer antibiotic sprays in conjunction with the biological control agent, showing that A506 can be introduced in an orderly fashion into pear production.
Highlights: While previous small-scale tests were positive, this was the first large scale commercial test of A506 (Frostban B() applied in conjunction with varying (50% and 100%) frequencies of antibiotics. Results strongly confirmed earlier results showing the additive control of A506 to any level of antibiotic use. Most significantly, control using 50% of the normal number of antibiotic sprays with A506 was equal to a 100% frequency antibiotic program. Disease was even further enhanced under a full schedule of antibiotics plus A506. Also, A506 survived other materials used for pear scab and codling moth control.
Antibiotic cost ranges from $200 - $400 per acre. A506 (Frostban B() is projected to cost $35 - $50 per acre. Thus growers can save up to $200 per acre in material costs plus reduced application costs. Since russet and frost damage was also reduced, savings may also be achieved in these areas as growers' confidence in A506 increases.
A well-attended field meeting demonstrated grower interest in this project. Preliminary results were publicized in a widely-read trade journal. Further dissemination of results via grower meetings, newsletter, trade journals, etc. assures great interest in trying Frostban B in the 1995 season.
Host status of crop and weed species to plant-parasitic nematodes in California: Development and release of a PC/MAC-platform database.
Principal Investigators: H. Ferris, Nematology, Davis; E. P. Caswell-Chen, Nematology, Davis
Situation: Selection of resistant cultivars, rootstocks or rotation crops requires identification of nematode species (or races). New, rapid and accurate nematode-identification techniques include isozyme- and DNA-based markers. However, most nematode identification still relies, and will continue to rely, on morphological and anatomical characters. Information on plant, crop and cultivar host status to nematode species is necessary for crop choice. Much of the information is available in the literature, but it is dispersed and difficult to find.
Highlights: This project has been funded from various sources over the past three years. Primary funding has been from the UC Integrated Pest Management Project. Smith-Lever funds partially supported the project for five months during 1994. The database:
Elm leaf beetle management and demonstration.
Principal Investigator: M. L. Flint, UC IPM Project/Entomology, Davis
Co-Leaders: S. H. Dreistadt, UC IPM Project, Davis; D. K. Giles, Biological and Agricultural Engineering, Davis
Situation: Elm leaf beetle, Xanthogaleruca luteola, is the most serious pest of elm trees in the warmer inland areas of California, defoliating the most susceptible trees annually. For many central valley cities, elm leaf beetles account for more citizen complaints than any other pest. Many communities have relied on annual insecticide injection for ELB control. However, repeated injections damage trunks and the preferred material (Bidrin) became unavailable as of spring, 1992. Whole tree sprays of carbaryl and other broad spectrum insecticides, which have been used in the past, are no longer an acceptable alternative in public areas because of potential human health and environmental hazards. Effective management requires a good understanding of elm leaf beetle biology and use of a variety of techniques in an IPM program; however, city and county parks managers have not had access to this information or training in the use of specific IPM techniques.
Highlights: This one year Smith-Lever project demonstrated the use of several more environmentally sound management methods that can be integrated into an IPM program for elm leaf beetle and used by arborists now. In the research aspect of this project, we evaluated the efficacy of a newly available microbial insecticide, applied with conventional high volume air blast sprayer and with ultra-low volume equipment developed especially for this project, on trees in the City of Davis and on the University of California Davis campus. Preliminary results show less than 10% survival of first instar larvae on treated trees and a significant reduction in mid season foliar damage on trees treated with a combination of the microbial insecticide Bacillus thuringiensis variety tenebrionis (Bt) and insecticidal oil with both types of application equipment compared with untreated control. Both control and treated trees were treated with a trunk banding of carbaryl or fluvalinate. Final results of this research will not be available until all data is analyzed.
A one-day workshop for public agency park managers and farm advisors was held on June 28, 1994. Fifty participants from northern and central California public agencies attended and improved their knowledge of elm leaf beetle biology, ecology, biological control and management options through hands-on activities. The workshop included a tour of the Davis demonstration trees, hands-on experience with ULV spray equipment, use of the degree-day model for timing treatments, practice in use of monitoring techniques and decision guidelines, identification of different life stages of the pest and biological control agents including recently imported parasites, and an introduction to the available pest control materials including the different strains of Bt and insecticidal oils. Eighty-eight per cent of the participants stated they would or probably would change the way they managed elm leaf beetle as a result of the program; because we had representatives from more than half the major cities in north central California, who are the primarly people responsible for managing this pest in the state, this should have a significant impact. A comprehensive syllabus for landscape managers on biology, ecology, monitoring and management of the elm leaf beetle, including a copy of the degree day utility computer program, was produced for the workshop. A four page leaflet on elm leaf beetle identification, biology and management was developed and made available for wider distribution through UCCE county offices as a DANR publication.
IPM Extension in cotton: New needs and demands caused by the silverleaf whitefly in the San Joaquin Valley.
Principal Investigator: P. B. Goodell, UC IPM Project, Kearney Agricultural Center, Parlier Budget: $5,000
Situation: Cotton is grown on over a million acres in the San Joaquin Valley. During the 1980s insecticide/miticide use was calculated to be between 1 to 2 applications per field. Insecticide use has increased since 1991 due to several factors: increased reliance on more disruptive products (e.g. pyrethoids), more aggressive protection of early season fruiting positions, a shift in cotton varieties and species (e.g. Pima), and the introduction of new pests. Increased awareness is required by the industry is required to avoid creating more disruption in the established IPM system.
In addition to insects and mites, nematodes are a major soil borne pest. Since 1990, when 1,3 dichloropropene use was suspended, cotton producers and PCAs have had a need for educational outreach about pest management alternatives for fumigant nematicides.
Highlights: Primary use was made of cotton production meetings already scheduled by local cotton Farm Advisors during May, June, and July. These meetings are held in four locations throughout the Valley and concentrate on analysis of current production problems. A total of 11 meetings were conducted with total contacts over 2000 growers and PCAs who manage over 50% of the cotton in San Joaquin Valley. No estimates are available for yield or quality increases, but it is projected that timely insect management information played role in preventing a decrease in quality caused by aphid honeydew. Unfortunately the 1994 season experienced heavy insect pressure (mites and aphids) in some areas and insecticide use was increased considerably in these areas. Five additional meetings were conducted which provided hands-on opportunity to identify this pest or quantify its presence in a cotton field. A total of 250 PCAs were contacted during these training workshops. Educational materials provided include three articles in the California Cotton Review (the newsletter of cotton extension), Pest Notes, industry sponsored brochures, and toll free access to cotton insect status reports. General outreach activities also included radio programs (3), and interviews for agricultural publications (3).
Integration of Farnesol, an environmentally kind, natural ant repellent, into IPM programs for control of arthropod pests of citrus.
Principal Investigators: E. E. Grafton-Cardwell, Entomology, Riverside/Kearney Agricultural Center, Parlier; P. A. Phillips, UC IPM Project, Ventura County; H. H. Shorey, Entomology, Davis/Kearney Agricultural Center, Parlier
Situation: As citrus growers move toward low pesticide input or "soft" pesticide management of arthropod pests, persistent, secondary problems with aphids, mealybugs, and soft scales develop. Close inspection of the trees frequently reveals that they are being "worked" by ants, which come from nests in the soil. The ants climb the trees and tend the aphids, mealybugs, or scales, obtaining honeydew from them, protecting them from parasites and predators that otherwise would regulate their numbers, and moving them to fresh locations as necessary.
A great deal of fundamental research has been conducted to elucidate the many naturally occurring compounds that repel or otherwise inhibit the activities of ants. Most of the chemicals are very potent behavior inhibitors, having effectively repelled ants for millions of years. Shorey and coworkers have conducted field research demonstrating the feasibility of using farnesol and related chemicals for disruption of foraging of Argentine, native gray, and native fire ants on citrus. We expect that these demonstration plots will show that when farnesol is used for a long period of time (probably two or three years will be needed to obtain equilibrium), parasitization of homopterous pests and predator activity will increase, providing selective pest control that is desirable in this time of decreased emphasis on conventional pesticides. With few available pesticides still effective against ants, having this additional ant control tool in our arsenal is desirable even for "conventional" pest control programs and is essential in more sustainable and organic programs.
Highlights: This was the first year of funding to demonstrate the effectiveness of farnesol as an ant repellent in citrus. Eight different plots were established.
Phytotoxicity field trials (farnesol, farnesol+stickem, stickem alone directly applied to the trunk): 1) At the Kearney Agricultural Center, navels were planted during 1994 and treated and no negative effects have been observed on young trees, 2) At the Lindcove field station, fruit-bearing grapefruit trees trunks treated and the farnesol and the farnesol + stickem treatments have caused an 3 inch band of the outer bark to peel.
Repellency field trials (farnesol, farnesol + stickem, and stickem applied to the trunk in cotton soaked strings wrapped around duct tape as well as a standard Lorsban spray and an untreated control): 1) At Lindcove field station, young trees were planted in 1994 and native fire ant populations established, however, the treatments have not yet been applied. 2) In a commercial block in Porterville with gray ants, the treatments were established in the spring of 1994, and the farnesol+stickem treatment and the Lorsban have kept the ants at 95% control for 8-10 weeks. We will evaluate parasitism in October, but expect to take several years to see differences in treatments. 3) In Ventura County, there were four orchards; a lemon and a Valencia orchard with one acre sized plots, and a lemon and a Valencia orchard with replicated 5-tree plots comparing just Lorsban and farnesol+stickem-treated string for control of argentine ants. Changing farnesol+stickem-treated string every 10-12 weeks gave 100% control during the 30 weeks of the test. Lorsban was applied every 12 weeks (legal limit) and gave 6-8 weeks of control when applied as a broadcast spray and 10-12 weeks of control when applied by a concentrate backpack sprayer.
Delivering an IPM system to citrus PCAs.
Principal Investigators: E. E. Grafton-Cardwell, Entomology, Riverside/Kearney Agricultural Center, Parlier; N. V. O'Connell, UC Cooperative Extension, Tulare County; P. B. Goodell, UC IPM Project, Kearney Agricultural Center, Parlier
Situation: During the past decade, various arthropod pest management research and implementation programs have been established in citrus in the San Joaquin Valley to decrease grower dependency on pesticides. These projects have helped to establish economic injury levels and sampling strategies for each of the major pests of citrus (citrus red mite, citrus cutworm, citrus thrips, fruit tree leafroller and California red and yellow scale) as well as key natural enemies (predatory mites and parasitic wasps). In spite of all the research has accomplished, growers and PCAs (Pest control Advisors) continue to struggle with learning how to efficiently monitor citrus pests and assess the potential for damage they cause while minimizing use of broad spectrum pesticides. Our project will provide growers with seasonal trends in arthropod pest populations, train a core group of PCAs in intensive arthropod monitoring, demonstrate that non chemical approaches can be effective, educate citrus growers at large through field day sessions and through surveys analyze grower and PCA use of the demonstrated IPM techniques.
Highlights: This was the third year of funding to support monitoring of pests and natural enemies of citrus in the San Joaquin Valley. Six of the 12 orchards use a selective pesticide program and six use a broad spectrum pesticide program for pest control. We continued to compare these two strategies and explained to the growers and PCAs the reasons for problems and the methods for greatest success. We intensively trained 12 PCAs in weekly pheromone monitoring of California red scale; previously many had only counted male scale once per flight. More intensive pheromone trap monitoring helps the PCAs time insecticide applications and parasite releases more carefully. We monitored degree day units in four of the orchards and projected male scale flights and crawler emergence for the PCAs. We produced 11 newsletters and mailed them to 250 citrus growers and PCAs in Tulare, Kern and Fresno Counties. Every week we updated the Fresno County Agline telephone message briefly describing the insect and mite counts from the Smith-Lever project. We conducted 3 field meetings (covering citrus cutworm and fruittree leafroller, citrus thrips, predatory mites, citrus red mite and citricola scale) to explain monitoring and identification of the insects. These meetings were open to all interested PCAs and growers (18-32 attendees at each session). We also had an intensive 2-day course in armored scale and parasite identification (22 participants). Five of the 6 orchards using the selective pesticide approach to pest management experienced citricola scale. We were able to detect the scale, teach the PCAs how to monitor for it and recommend methods of chemical control. Biological control of citricola scale is inadequate at the present time. This emergence of a secondary pest as broad spectrum pesticide use is eliminated was new information for some of the growers and was announced to the general public on radio and published in the Central Valley Farmer. The traditional broad spectrum (organophosphate, carbam ate, and pyrethroid insecticides) chemical control approach to controlling citrus pests used during 1994 was, 0 for citrus red mite, 2 sprays in 6 sites for worms, 9 sprays in 6 orchards for citrus thrips and 4 sprays in 6 orchards of pesticides for armored scale. Thus, traditional program growers used a total of 2.5 pesticide applications during 1994. The growers using the selective pesticide approach used 0 sprays for citrus red mite and worms, 5 sprays in 6 orchards for citrus thrips (used botanicals and Agri-mek instead of broad spectrums), and 1 for armored scale (spot spray with oil instead of broad spectrums) and 1 for citricola scale. IPM practicing growers used an average of 1.2 pesticide applications during 1994. Thus, the IPM practicing growers monitored more frequently and reduced their overall pesticide use in addition to using safer pesticides during 1994. It is important to note that growers practicing IPM do not always use fewer pesticides because the selective pesticides are often less effective than broad spectrum pesticides. For example, during the 1992-93 field seasons when citrus thrips pressures were high, those growers using IPM approach sprayed more pesticides for citrus thrips control than the traditional growers.
Validation, implementation and demonstration of an integrated pest management program for pests produced from southern California egg ranches.
Principal Investigators: N. C. Hinkle, Entomology, Riverside
Situation: Historically, conservation of beneficial arthropods combined with cultural practices and manure management have been the bases of fly suppression strategies employed on poultry ranches. With changes in the regulatory climate, poultrymen are often forced to abandon these practices. Implementation of integrated pest management systems on poultry ranches in southern California is dependent on their acceptance by both the county health department inspectors and vector control district personnel. It is critical to demonstrate the feasibility and workability of biocontrol and cultural manipulation for pest management on egg ranches.
Highlights: Cooperation by producer groups, especially the Pacific Egg and Poultry Association and the Inland Empire Poultrymen, Inc., has been excellent. Five collaborators have allowed us access to their ranches, permitting field validation and demonstration of innovative pest management strategies. During the next phase, we will be soliciting participation by local vector control districts and county health departments, both of which have jurisdiction over poultry operations in their areas.
Funding was for 0.75 year. Sixty-six vector control personnel and county health department inspectors were trained, along with 43 poultrymen and their managers. In addition, we were invited to present an overview of our program at the spring conference of the Pacific Egg and Poultry Association, with over 50 attending the session.
As is not surprising when transferring technology from the research stage to field implementation, we were taken aback by many of the discoveries we made. Probably the most notable finding was that the entomological aspects of problems are not so significant as the social, regulatory, and legal ramifications. Surveys of members of the Inland Empire Poultry Producers revealed that 78% consider flies their most pressing public relations problem. The same number have had neighbors complain to them about flies but, so far, the vast majority of them have been able to defuse the situation without it becoming a significant problem.
To reduce pesticide usage, almost three-quarters of the producers would be willing to adopt the practice of staggered manure removal, to conserve the beneficial arthropods. However, only a third of the responders believe that biological and cultural controls are currently working for them. Barely half of them are maintaining a build-up system, to foster natural fly suppression. 45% have been forced to go on a regular (weekly or more frequent) cleanout, to satisfy the county inspectors. Areawide, probably more than 80 of the 103 poultry ranches will rely primarily on biological and cultural control, if the regulatory climate permits.
Seventy percent of the responders consider insecticides to be important in their fly management programs. All of them use baits to some degree (ranging from 5 to 99% of their fly control strategy). Half of them use larvicides, but do not rely on them heavily; none are used more than 20% of the time. Adult fly sprays typically account for less than a third of the insecticidal use in these facilities, ranging from only 1% up to 80%. Less than 10% believe that insecticides work as well now as they did in the past. 60% say that baits are less effective. 88% say that adulticides are less effective than years previously. But 80% say that larvicides still work as well as in the past. Following this program, reduction in pesticide usage will probably involve adulticides, while use of the more environmentally compatible larvicides will likely increase.
Three-quarters of the producers say they currently enjoy a good relationship with their Vector Control District; however over half of them do not anticipate the same level of cooperation in the future. Regarding future fly abatement regulations, all of the producers (except one who has taken a "wait and see" attitude) are confident that future regulations will not benefit the poultry producer or improve relationships between the poultrymen and their neighbors. Three are willing to concede that such regulations may actually improve the fly situation, though.
It is apparent that the current need is for Cooperative Extension to provide the regulatory agencies the background training they need to knowledgeably perform their jobs. In addition, it is critical that CE assist in an advisory capacity to both the poultrymen and the regulators; this is resulting in development of individualized manure and pest management plans for poultry ranches. Simultaneously, CE has been asked to provide input during the drafting of interim regulations affecting the poultry industry in southern California.
Cooperative Extension has a long history and well-deserved reputation for real-time transfer of research results to the State's poultry producers. These innovative businessman have typically incorporated beneficial discoveries into their management plans and profited thereby. We anticipate that CE will continue to serve the egg producers both by their research efforts and by serving as liaison regarding regulatory issues affecting the poultry industry. In conclusion, Cooperative Extension efforts obviously need to be directed more toward education and training of personnel involved in inspection of poultry facilities.
Orchard floor management to optimize pear fruit finish.
Principal Investigators: G. McGourty, UC Cooperative Extension, Mendocino County; S. E. Lindow, Plant Pathology, Berkeley.
Situation: Pear growers generally receive a premium for fresh market fruit. The percentage of fruit that can successfully be packed out is often limited by russeting of the fruit caused by IAA producing bacteria such as Erwinia herbicola that migrate from vegetation growing on the orchard floor into the lenticels of developing young pears. The bacteria then produce IAA as a metabolic byproduct, and corky cells develop on the lenticels, resulting in russeting. Work done in previous seasons by the authors have shown these bacteria colonize plants growing in the sward beneath the trees differently, with grasses generally supporting large numbers of IAA producing bacteria, and legumes such as subclover and bur medic supporting smaller numbers. Eliminating all vegetation beneath the trees with glyphosate sprays will also improve fruit finish by decreasing bacterial populations that can subsequently cause fruit russeting. In 1992-93 growing season, we demonstrated that selected legume covercrops can significantly improve pear fruit finish equal to chemical mowing with glyphosate. Planting grass covercrops such as perennial and annual ryegrasses could also significantly increase russetting compared to these treatments. The 1992-93 season was a very cool, wet year with considerable russetted fruit. In 1993-94, the experiment was repeated without the grasses included as treatments. In their place, additional legumes (crimson clover and red clover) were tried.
Another aspect of the trial was to establish covercrops with no-till seeding equipment to eliminate the risk of soil erosion that can occur with late season tillage along the Russian River. Small seeded perennial legumes continue to be difficult to establish in the fall.
Highlights: This project was a high profile study for the UCCE Plant Science Program. Sixty people from the three neighboring counties attended a field day in April to see the plots and hear about the progress of the study. No till seeding was also demonstrated. Cover crops are being more widely planted in Mendocino County, with the pear industry planting about 300 acres in the coming year.
Since there is no chemical treatment available for russet control, we are providing a new methodology for improving fruit packout that involves no chemicals. Reduction in the use of glyphosate is certainly possible. Presently, about 2500 acres are chemically mowed. I hope that in the future, less chemical mowing will be needed due to the successful adaptation of covercrops to pear culture. It is too early to tell if growers are willing to spend the money and take the time to learn how to properly implement a successful covercrop program.
During the past growing season, which was a difficult one in the market place, the cooperator in this trial, a Mendocino County grower/shipper organization, sold their fruit to a baby food company on the basis of their committment to IPM and a conscientious effort to reduce pesticides in their approach to farming. Many other grower/shippers were unable to sell fruit due to greatly depressed market prices. Consequently, I suspect that there will be a continuing interest in covercrops and other sustainable practices that lessen the need for pesticides and petrochemical inputs.
Hands-on participation in demonstrations of grape leafhopper management in south-central coast winegrapes.
Principal Investigators: P. A. Phillips, UC Cooperative Extension, Ventura County; M. L. Bianchi, UC Cooperative Extension San Luis Obispo and Santa Barbara Counties
Situation: Western grape leafhopper (GLH) is the primary target for organophosphate insecticides in vineyards in northern San Luis Obispo county and areas of northern Santa Barbara county. Currently, growers do not appear to be following the sampling and treatment guidelines for GLH treatment as described in the grape IPM manual or the grape IPM guidelines. Repeated summer applications of dimethoate or carbaryl not only preclude any late season increases in the egg parasite Anagrus but aggravate Willamette mite populations.
Highlights: Mass trapping with yellow sticky tape was effective in two of three vineyards in partially reducing the number of overwintering GLH adults migrating into the vineyard from neighboring riparian areas. GLH overwintered within the vineyard in the third vineyard and mass trapping was only effective where the tape was in place. Biorational insecticides effectively reduced GLH early instar nymphs in one vineyard.
Results from this project have been presented at grape grower meetings in San Luis Obispo and Santa Barbara counties, the1994 Central Coast Winegrowers Technical tour and 1994 CAPCA regional and statewide meetings, National IPM Symposium, and the 1993 and 1994 UC Grape IPM workgroup meetings.
Implementation of the use of Bacillus thuringiensis for control of peach twig borer in stonefruits.
Principal Investigators: C. Pickel, UC IPM Project, Sutter-Yuba Counties; W. Barnett, UC IPM Project, Kearney Agricultural Center, Parlier
Situation: Peach twig borer (PTB) is a serious pest of most stone fruits, including cling peaches, prunes, and almonds. Historically, control of PTB has been accomplished by treating overwintered larvae with an oil and organophosphate combination during the dormant period. Recently, there are indications that overwintering PTB larvae are becoming resistant to organophosphates. The organophosphates in these dormant treatments are also suspected of drifting to nearby crops, getting into waterways, and killing raptors, especially hawks, present in orchards with small winter territories.
Through research and demonstration over a 5 year period we have successfully demonstrated control of PTB in commercial orchards with BT during bloom comparable to that achieved with the standard grower programs. This year the program was expanded to involve growers and PCAs in monitoring.
Highlights: This fourth year of the BT program was a hands-on training for farmers and PCAs to learn monitoring skills for the key pests as well as the secondary pests. The program has been more readily embraced by almond growers in the Sacramento Valley growers, and we know approximately 17% of the acreage tried this program this year in addition to the 17 participants in the program. This is an increase from 1% last year in the Sacramento Valley. Prune growers are still hesitant to try the program. Many of the 11 participating orchards are in the Sacramento River Restoration Project operated by the US Fish and Wildlife. Demonstration of successful BT programs on these farms is important before more prune growers adopt the practice. We documented good control of PTB from an aerial application compared to a untreated area of the orchard within one of these prune orchards. One cling peach grower participated in the program and used no in-season sprays for PTB. At 50% adoption rate, this program would save 500,000 pounds (AI) of organophosphate.
Grower adoption of grass interseeding in aging alfalfa stands: Implementation and evaluation.
Principal Investigators: T. S. Prather, UC IPM Project, Kearney Agricultural Center, Parlier; R. F. Norris, Vegetable Crops, Davis; C. L. Elmore, Vegetable Crops, Davis
Situation: Weeds normally are controlled early in their life cycle, from the seed to early seedling stage. Development of monitoring programs, threshold models, and prescribing post-emergent herbicides all require identification at these early stages to be most effective. Currently, there is no manual for California's weeds that focuses on the seed to seedling stages. Pest control advisors have expressed interest in seedling identification and welcome the idea of a new manual and computer identification program.
Highlights: The project has received one year of funding. Our training programs focus on hands-on identification of weed seedlings. These programs target growers and PCAs and this year we have trained 335 people, statewide. We continue to photograph our seedlings, using Jack Clark's expertise. The quality of our slide set is excellent. These slides will be incorporated into future training sessions. Our first year slide collection will include slides of 40 weed species at 3 stages of growth. We have collected morphological data on 34 weed species and will obtain data on an additional 15 species this fall. Our educational materials being produced this fall include slides of the seedlings and a computer based identification system that includes data on 34 species. In addition, we are growing seedlings for use in educational programs in the coming year.
Grower adoption of grass interseeding in aging alfalfa stands: Implementation and evaluation in Madera and Fresno Counties.
Principal Investigators: T. S. Prather, UC IPM Project, Kearney Agricultural Center, Parlier; R. Vargas, UC Cooperative Extension, Madera County; S. Mueller, UC Cooperative Extension, Fresno County
Situation: Alfalfa stands decline with age, making them susceptible to invasion by weeds. Nearly all the alfalfa acreage (105,000 acres) in Fresno and Madera counties is impacted by weeds. In the last year of production, the only herbicide that can be used without plant-back restrictions is paraquat. Winter weeds can be controlled with paraquat but summer grasses can not, and weeds contribute up to 30% by weight of the total forage yield. Diuron is often used in combination with paraquat but it has a 1 year plant-back restriction. A grower's choice for rotation is limited to cotton if diuron or hexazinone is used in the previous year. In addition, paraquat and diuron can result in a 40% to 50% loss in yield in the first cutting because of herbicide injury. Hay can be discounted from $10 to $40 per ton for containing weeds and many buyers will not accept hay that has coastal fiddleneck, common groundsel, and yellow or green foxtail.
Highlights: Our initial survey of growers indicated that 20% of them have interseeded grasses into old alfalfa stands. We planned to increase the adoption of the technique through traditional means, e.g. field meetings, newsletters, etc., and through non-traditional means by way of a seed give-away program administered through the seed companies that sell most of the alfalfa seed in Madera and Fresno counties. This year our field meeting attracted 12 growers. We increased the number of participating growers in the seed program from 4 to approximately 20 this year. We will present results of our large demonstration plots at the Alfalfa Symposium, reaching approximately 200 people. We also had a poster display at the California Weed Conference this year reaching an additional 150.
Our research shows an increase in production during the first two cuttings but no difference after that. Production over the entire season showed higher production last year but no difference in production for this year.
Approximately 5% of the acreage is currently using the technique and the maximum in any given year would be 25% of the acreage. Herbicides are not needed on the interseeded areas. In addition, our research shows that spraying for alfalfa weevil should not be needed. Therefore, on affected acreage, 2 spray applications could potentially be avoided when interseeding is done.
Our educational materials include 3 poster displays, a promotional pamphlet outlining the technique, a symposium article, 2 PPQ articles and several newsletter articles. The pamphlet has been especially useful. The seed companies use the pamphlet to introduce growers to the technique. We produced 400 pamphlets and we need another print run because we are out of pamphlets. We also have a slide set for use in presentations on the topic.
SOLARIZATION FOR ORCHARDS
Evaluation of post-plant polyethylene mulching for establishment of Prunus orchard trees in the San Joaquin Valley: Effects on pest management and conservation of irrigation water.
Principal Investigators: J. J. Stapleton, UC IPM Project, Kearney Agricultural Center, Parlier
Situation: The successful establishment of perennial crops is a critical first step in a long-term investment. Protection from soilborne pathogens, nematodes, and weeds, as well as maintenance of proper irrigation and fertilization regimes is necessary. With increasing constraints on availability of irrigation water due to limited supply and public pressure, and on chemical soil fumigants due to regulatory action, mulch and drip irrigation can provide the backbone for a successful, holistic orchard management plan.
Highlights: Prunus trees, including almond, apricot, and peach, have now been growing under the mulch/drip irrigation management system for three years following planting. On-farm demonstrations of citrus, pistachio, and olive trees which were mulched during their first or second year after planting are now underway. Observations and indicators show that trees are thriving under the mulching treatment in the San Joaquin Valley, even though mulched trees were given 50-85% less irrigation water than conventionally-grown trees. Mulching and methyl bromide fumigation both decrease numbers of soilborne pathogens. Reductions in pesticide applications of up to 75%, and in irrigation water and fertilizers of up to 85% over the first 5 years of growth can be expected with this holistic management system.