Long Live "MagNet": Positive Points for IPM Tool Use

Dr. Alexandra Stone, OSU State Vegetable Cropping Systems
Amy J. Dreves, IPM Research and Extension Entomologist

Oregon State University

Department of Horticulture
4017 Ag & Life Science Bldg
Corvallis, OR 97331-7304

(541) 737-5461
(541) 737-5576

stonea@science.oregonstate.edu
drevesa@science.oregonstate.edu
Fax (541) 737-3479

Executive Summary

The primary goal of this project is to reduce dependence on chlorpyrifos in cruciferous crop production in Oregon. Root crop and above-ground Brassica growers are highly dependent on chlorpyrifos (Lorsban™, an organophosphate insecticide) for control of a very destructive pest, the cabbage root fly (CRF; cabbage maggot, Delia radicum (L.)). The Clean Water Act, the Endangered Species Act, OR Senate Bill 1010, the OR Plan for Salmon and Watersheds, and the Food Quality Protection Act have set in motion the development of a basin-wide water quality management plan and a statewide pesticide reporting use initiative. Strict environmental regulations over chlorpyrifos, as well as growing doubts over its efficacy, have led growers to seek new management strategies.

The supporting objectives of this project are: 1) to develop and implement a 1-2-3 IPM toolbox, 2) to define the current impact of CRF on above-ground Brassica production and the importance of chlorpyrifos as a control measure, 3) to continue to build a collaboration between growers and agricultural professionals, and 4) to inspire and facilitate grower IPM interest and adoption.

Program staff are refining the details of seasonal activity and lifecycle of CRF, determining factors that increase plant susceptibility to CRF damage, creating a regional GIS “maggot map” with monitoring information from sample sites, and validating monitoring techniques on the farm for detecting CRF growth stages and crop damage. Since the creation of “MagNet” in the fall of 2000, over 150 fields in commercial production of turnips, rutabagas, and radishes have been intensively monitored.

These monitoring data will help validate a degree-day model for Oregon growers. Efficacy trials will continue through 2003 to test alternative chemistries (e.g. Metarhizium, Spinosad, Fipronil, and treated seed formulations), timing of treatments, application efficiency, and cultivation techniques. In-field no-spray strips will be evaluated for the third year to determine the importance of chlorpyrifos and impact of CRF. Alternative strategies such as spatial management of fields, crop sanitation and cultivation, and plant collars are being explored. Our goal is to reduce chlorpyrifos use by one third in five years. Management strategies developed in root crops over the seasons of 2000-2003 are being applied to other cruciferous crops such as cabbage, broccoli, and cauliflower. These strategies could be applied to crops susceptible to onion, seed corn and carrot rust fly maggots, so the ultimate impact of this project will be widespread.

“MagNet” presently includes several collaborator growers (including three root growers, three above-ground and two seed Brassica growers); six OSU extension-research staff; two private crop consultant collaborators; and other interested growers. This group meets twice annually to share experiences and review, evaluate, and develop the future work plans. The project is evaluated through surveys and “the PEST Plan” Point Questionnaire that assess grower management practices, attitudes, and progress towards use of IPM practices. All project outcomes will be presented at grower meetings and field days and published on the MagNet website, in a newsletter, and as extension bulletins. A region-wide monitoring and reporting system for regional vegetable growers will be implemented in summer of 2003 on VegNet, a means of broadcasting information in the Valley thru Fax, email, and letter.

Objectives

The overall goal of this project, MagNet, is to reduce dependence on chlorpyrifos in cruciferous crop production. The supporting objectives are:

To implement a 1-2-3 IPM ToolBox (a collection of IPM tools)
To quantify the current impact of the cabbage root fly and importance of chlorpyrifos in above-ground Brassicas
To continue to build a collaboration between growers and agricultural professionals
Ultimately, to inspire grower IPM interest and adoption.

Justification

Root crop growers are highly dependent on chlorpyrifos (Lorsban™, an organophosphate insecticide) for control of the pest, the cabbage root fly (CRF; cabbage maggot, Delia radicum (L.)) (Quarles, 2000; Sears, 1998). Root crop production requires a high degree of control of CRF, as a single maggot can generate an unmarketable root. Chlorpyrifos has been shown to be neurotoxic to animals and aquatic organisms. EPA has invoked the 10-fold safety factor for chlorpyrifos, and all uses are at risk of termination. Chlorpyrifos is the second most frequently detected insecticide in surface waters of the Willamette Basin (Wentz et al, 1999). This basin will be the focus of intense environmental scrutiny in the next five years. The Clean Water Act, the Endangered Species Act, OR Senate Bill 1010, the OR Plan for Salmon and Watersheds, and the Food Quality Protection Act have set in motion the development of a basin-wide water quality management plan and a statewide pesticide reporting use initiative. The fresh market production region (the Canby-Aurora area south of Portland) is rapidly urbanizing and farms are surrounded by homes, increasing the likelihood of human exposure to chlorpyrifos.

This project was initiated in 2000 in root crops. Root crops have been an excellent model system in which to investigate CRF management strategies over the past 2 ½ years. The system is sensitive, as even very low levels of infestation can be detected. Root crops are typically grown in relatively low acreage serial plantings throughout the season, so management effects on both spatial and temporal incidence can be assessed. Control measures developed in the root crop "model system" would be applicable to above ground cruciferous crops, and potentially also to crops susceptible to similar pests such as onion and seed corn maggot. Therefore, we will now transfer what we have learned to broccoli, cauliflower, and cabbage crops grown on over 4,000 acres and 180,000 acres nationwide (www.ams.usda.gov).

1) Implement a 1-2-3 IPM ToolBox
No viable monitoring strategy currently exists for CRF on any crop (Cornell Cooperative Extension, 1999; UC IPM Project, 1985; personal communication, Jim Todd, Ag consultant). Predictive models have been developed for CRF in Great Britain, Canada and New York, but not for the Pacific Northwest. There is also little regional data on CRF population dynamics. Prophylactic sprays without monitoring is the current practice. This project will continue to work towards the development of a practical and effective monitoring and reporting system to better select and time treatments to pest incidence and a collection of alternative management practices. A diverse collection of monitoring and alternative management strategies makes up the 1-2-3 IPM Toolbox. We plan to transfer the ToolBox into the hands of the growers after evaluation in 2003-2004.

The backbone of this project is monitoring, including adult flight and crop damage assessment (CDA). CDA has strong scientific and educational value for several reasons, as it 1) is presently conducted at some level by growers at harvest, so we have simply developed strategies to make these assessments efficient and quantitative, 2) improves grower understanding of CRF life cycle and behavior, 3) is an efficient and inexpensive means of quantifying CRF incidence and economic impact, 4) permits growers to independently evaluate the impact of experimental management strategies, 5) is an inexpensive means of generating spatial and temporal region-wide CRF data, and 6) will be used to relate damage levels to distances from previously infested fields (see Figure 5, page 11) and validate a predictive degree-day (DD) model to predict low risk and high risk periods.

In addition to CDA, monitoring of CRF developmental stages and adult flight is used to refine and validate the predictive degree day model each winter. In the winter of 2003-4, the potential for full implementation of a region-wide predictive model and viable monitoring system is great!

2) Define the current impact of the cabbage root fly and importance of chlorpyrifos.
The goals of this objective are to generate analyses of 1) the economic impact of CRF in Brassica crop production, and 2) the efficacy of chlorpyrifos for CRF control. These analyses will be used to document the importance of CRF control in Brassica production and the importance of chlorpyrifos as one strategy in an overall IPM system. They will also be used to help get registrations for new chemistries for CRF in Oregon.

3) Continue to develop a collaboration of growers and agricultural professionals
Fresh market growers are an under-served grower group in Oregon. They do not have a commission, so the growers have had few reasons to collaborate in the past - either with each other or with OSU personnel. (We are the first researchers to receive research money from this group). For this reason, this collaboration is novel for this group. The purpose of the collaboration was to bring together a diversity of opinions, experience, and expertise in CRF management in order to more efficiently and effectively design and test new management strategies. Currently, the collaboration closely involves eight pilot growers, six OSU extension staff, and two private crop consultant collaborators. This group continues to meet at least twice annually to share experiences and data and plan, review, and evaluate the project.

4) To inspire grower IPM interest and adoption.
All aspects of the project are designed to inspire grower interest in and adoption of IPM practices - from learning about CRF phenology through monitoring and crop damage assessment, to providing a supportive, collaborative, and information-rich environment for IPM and systems thinking. This grower group has previously had little to no exposure to IPM theory or practice, so the growers are very excited about their participation in this project. We see this project as merely the first step in an ongoing process of implementing IPM in fresh market production in Oregon and now transferring knowledge and experiences into the processed vegetable and seed industries

Overall Summary

There are several published degree-day models for predicting adult flights of CRF from Europe, Canada, and northeastern US (Jyoti et. al, 2000; Collier and Finch, 1985; Bracken et al, 1988). Currently no CRF degree-day models have been developed in Oregon. After reviewing the models and studying local temperature and emergence data over the past 2 years, we are getting closer to releasing a predictive model. In this model, thermal units are accumulated beginning January 1 with a standard base threshold of 4.3 °C is used, based on literature indicating little or no CRF development below this threshold. No high temperature cut-off is used because daily temperature means in the northern Willamette Valley normally stay below 25 °C. To validate this model, we are using spring emergent traps with fall pupae buried under them (Dreves et.al. 2000-2002 unpublished) and yellow water traps (Finch, 1990 & 1992) to detect adult flight. Field egg incidence is evaluated before and after flight. Preliminary data indicates that there were four concerted egg-laying periods and five flight periods in 2002. The model closely predicted spring adult emergence for both the overwintering (March 21st - April 9th) and F1 generations (May 31st-June 6th) in 2002 (Figure 1).

(Figures not online but are available upon request)
Figure 1. Preliminary CRF Degree-Day Model Predictions
Figure 2. A wide array of flight monitoring tools.
Figure 3. A technique for estimating egg levels.

Continued monitoring of adult flight (Figure 2), egg-laying (Figure 3), and damage is required to determine whether there is sufficient coherent structure in the region to justify a region-wide monitoring program and validate techniques so they can be passed on to growers. We showed that earlier plant growth stages had significantly higher number of eggs than later growth stages.

We have been working with growers on crop damage assessment to help them understand the number of flights and the timing and impact of each flight. We refined CDA methods in 2000-2002, and we now have a practical, quick and accurate technique that growers are beginning to use in the field.

The importance of chlorpyrifos for CRF control on cruciferous crops in the PNW has never been quantified to our knowledge. There has been little conclusive research on the CRF impact as most studies have not successfully predicted incidence and have therefore conducted studies in which little damage occurred (Todd 1999, 2000).

In 2000, we showed in an on-farm trial that two well-timed Lorsban applications during the high risk period (peak egg-laying) generated the same level of control as five prophylactic applications, while improving the economics and reducing the environmental risk.

In 2001 & 2002, we conducted 7 trials and showed that seed treatments (Lorsban, Spinosad, and Fipronil; >85% less insecticide) showed lots of promise, particularly for radish growers. Levels of CRF protection lasted 3-4 weeks, the period of highest CRF-susceptibility in both radish and other root crops. Data also suggested that in-furrow treatments of liquid Lorsban or Fipronil were more effective than foliar treatments (Figure 4). We have also shown that applications timed to periods of high egg laying and greatest plant attractiveness (5-7 leaf stage) are most effective.

Approach and Outcomes

Objective 1. Implement a 1-2-3 IPM Toolbox.

Development of a predictive degree day model: A CRF phenology model is being further developed. The equation is: Thermal Degree-Days (DD) = (Max° C + Min° C)/2 – Base Temp (4.3°C). We are now validating the model with the monitoring tools described below. Daily temperatures are taken from a NOAA weather station in the heart of the root crop production area. Once the model is validated, we plan to publish our CRF model in 2004 on the OSU IPPC On-line phenology website used by many growers.
Monitoring techniques:
1) Adult flight. Adult flight is monitored through the use of miniature emergent cages and yellow water traps (most favored by growers-survey 2002). Water trap counts are not well correlated with crop damage, but are a useful tool to determine adult flight and to predict egg-laying events. Adult flies can be easily identified in the traps (after training on fly identification) and enumerated by staff and growers. We are designing a simple card that attaches to the trap that helps growers identify adult flies and record the numbers of flies. This appears to be a simple, inexpensive, and grower-friendly method to detect adult emergence.

2) Egg laying. Egg counts are monitored using a “visual egg scrape technique”, called ES90. Five clusters of 3 plants each are inspected in 6 areas of the field, totaling 90 plants. A knife is used to gently scrape the soil surface to find eggs laid in soil cracks. 3) Damage. Damage is assessed by randomly and destructively sampling 60 whole plants along a “M” transect in 6 regions of a field (M60). The developmental stage of CRF (larvae and pupae) is recorded to verify phenology model.
Alternative chemistries and application timing: Bob McReynolds (Fresh Market Vegetable Crops Extension, OR IR-4), Paul Jepson (Professor of Entomology and Director of IPPC), and Glenn Fisher (State Extension Entomologist) will collaborate in application timing, alternative chemistries, and equipment efficiency testing. Seed treatments (in collaboration with Alan Taylor, Cornell Seed Technology Specialist), furrow and foliar applications, Neemix drenches and other IR-4 recommendations will be evaluated at the experiment station in replicated trials planted to turnips in spring 2003 and 2004. Flight and egg levels will be monitored weekly and damage assessments will occur at 3, 6, 9, 12 and 15 weeks after planting.
GIS-based spatial and temporal management plan
Figure 5. GPS and GIS technologies and MagNet monitoring data are used to create this map of CRF damage levels across the region to relate damage levels to distance from previously infested fields designated by the red stars.

GPS and GIS technologies are being used to locate and map CRF incidence across the region in time and space and to relate damage levels to distance from a previously infested field (Figure 5). The goal will be to permit growers individually and as a group to manage plantings in time and space to minimize infestations. If appropriate, an on-line, interactive regional spatial management plan will be developed.

Objective 2. Measure of pest impact and importance of Lorsban.

Crop damage assessments (CDA): CDA’s obtained from MagNet farms throughout the season will be used to determine the overall economic impact of CRF in root crop production.
Chlorpyrifos on-farm efficacy trials: Unsprayed strips will be installed in six MagNet farm fields each year (03-04) during periods of high CRF incidence. CRF incidence and CDA will be collected to assess efficacy of chlorpyrifos, as growers suspect that CRF may have developed resistance.

Objective 3. To build a collaboration between growers and agricultural professionals.

Program recruitment and support: The collaboration was initiated in 2000 and a draft vision of the project was presented at the OR Fresh Market Growers annual meeting in January 2001. Twenty growers and agricultural professionals immediately signed up as project participants. A CRF monitoring and CDA workshop was held in March 2001 with 17 participants, and March 2002 and July 2002 totaling 40 participants. In spring 2002 we also held a user-friendly “Maggot Mapping” workshop to critique the GIS mapping tool. We have a monitoring workshop planned for grower employees in June 2003 and a Spatial Rotation & Alternative Chemistry workshop planned for September 2003 and June 2004. Our collaboration has now extended to processed broccoli and cabbage and Brassica seed growers. The MagNet collaboration (including growers) meets twice annually to share experiences and review, evaluate, and plan the project; staff and growers also communicate regularly one-on-one in the field. A “Pump-Us-UP” journal of phone conversations and in-field exchanges is used to document moments of success, positive interaction, and advanced IPM thinking to help evaluate progress towards better management practices.
Dissemination of results: Results will be disseminated: 1) through a weekly fax and/or email alert system (summer 2003), 2) on a “MagNet” website which will be linked to the OSU vegetable production site and the OSU-IPPC “On-Line Phenology” website, 3) at professional and commission meetings, 4) during an on-farm field days, and 5) in extension publications. We expect to generate publications on: 1) phenology and monitoring strategies for the cabbage root fly, 2) the economic impact of CRF and chlorpyrifos in Oregon, 3) the utility of a region-wide GIS monitoring and spatial management system.

Objective 4. To inspire grower IPM interest and adoption.

Growers participate in all aspects of the project. Growers learn about the CRF life cycle through monitoring and crop damage assessment in both group workshops and one-on-one weekly interactions with project staff. They received their first newsletter in January 2003 and will receive another in June and Nov 2003, which will include CRF alerts as well as information on IPM and alternative CRF management strategies. They participate in project meetings and workshops. IPM practices and attitudes are discussed within the group, and a positive point rating plan is being developed (modeled after a similar program developed by the Wisconsin potato and Vegetable Growers Association/World Wildlife Fund/University of Wisconsin collaboration for bio-intensive IPM potato production). Certificates are being rewarded to participating cooperators throughout the project period. Active participants receive a newsletter, monitoring kit containing: illustrated CRF developmental stage reference cards, monitoring technique handouts, spreadsheets for recording and reporting data, hand lens, miniature emergent cages, and a seasonal viewing jar.

Impact Assessment

The success of this project will be evaluated in winter 2003 and 2004. This project is young and growing rapidly. We realize that it is unrealistic to expect that grower practices will have changed significantly in such a short time frame. Therefore, we will evaluate 1) the potential for project outcomes to reduce chlorpyrifos use (in 2004 and the future) (e.g. Does the predictive model work? Can a grower predict damage by estimating egg levels? Are there effective alternative chemistries?) and, 2) grower practices and attitudes about IPM, and grower progress and intentions (whether these growers intend to adopt alternative CRF control strategies in the future) . We are developing, (with the help of 5 reviewers including a grower), an IPM rating system called “the PEST Plan” (formerly known as the P4Plan) to aid in quantifying a growers’ adoption of tools for managing pest. Individuals can evaluate how their current practices relate to the ‘ideal’ farm system. The PEST Plan provides a way to help measure a grower’s advancement towards ecologically-based management rather than chemically-intensive pest management. This information will be used by planners to determine whether project objectives have been met and to help evaluate the success of our extension program.

We will consider this project successful if we can: 1) predict that project outcomes will reduce chlorpyrifos use by one third within five years, and 2) detect significant differences in grower practices, attitudes, or intentions.

Literature Cited

Bracken, G.K. 1988. Seasonal occurrence and infestation potential of cabbage maggot, Delia radicum (L.) (Diptera: Anthomyiidae), attacking rutabaga in Manitoba as determined by captures of females in water traps. Can. J. Ent. 120:609-614.

Collier R. H., and S. Finch. 1985. Accumulated temperatures for predicting the time of emergence in the spring of the cabbage root fly, Delia radicum (L.) (Diptera: Anthomyiidae) Bull. Ent. Res. 75, 395-404.

Cornell Cooperative Extension. 1999. Integrated crop and pest management recommendations for commercial vegetable production. Cornell University.

Finch S., and B. Skinner. 1972. Studies on the adult cabbage root fly: alternative methods of population control. Rep. Natn. Veg. Res. Stn., pp.70-1.

Finch, S., 1989. Ecological considerations in the management of Delia pest species in vegetable crops. Ann. Rev. Entomol. 34:117-137.

Finch, S., 1990. The effectiveness of traps used currently for monitoring populations of cabbage root fly. Ann. Appl. Biol. 116:447-454.

Finch, S., 1992. Improving the selectivity of water traps for monitoring populations for the cabbage root fly. Ann. Appl. Biol. 120, pp1-7.

Finch, S., and C.M. Ackley, 1977. Cultivated and wild hosts supporting populations of the cabbage root fly. Ann. Appl. Biol. 85:13-22.

Jyoti, J.L., A. Shelton, and J. Banard, 2000. Population trends of adult cabbage maggot (Diptera: Antomyiidae) in relation to degree-day accumulation in upstate New York. Unpublished data.

Quarles, W., 2000. EPA restricts chlorpyrifos. IPM Practitioner 22(7):8.

Sears, S., 1998. Oregon County and State Agricultural Estimates. Oregon State University Extension Service. Special Report 790.

Sexson, D.L., 2000. Colorado potato beetle movement and survival in Wisconsin potatoes: the development of an area-wide management strategy. Ph.D. dissertation, University of Wisconsin-Madison, WI, 170pp.

Todd, J. G., 1999. Management and control of cabbage maggot, Delia brassicae, in cauliflower. Oregon Processed Vegetable Commission Reports. Salem, Oregon.

Todd, J.G., 1998. Management and control of cabbage maggot, Delia brassicae, in cauliflower. Oregon Processed Vegetable Commission Reports. Salem, Oregon.

UC IPM Project, 1985. Integrated Pest Management for Cole Crops and Lettuce. UC Statewide Integrated Pest Management Project, Division of Agriculture and Natural Resources, Pub. 3307.

US EPA Office of Pesticide Programs, 1998. Hazard Assessment of the Organophosphates. US EPA.

Wentz, D.A., 1999. The Quality of our Nation’s Water - Nutrients and Pesticides. U.S. Geological Survey Circular 1225, 82p.

Timetable

Jan-Mar 2004:

Release a sampling plan to predict flight, estimate egg levels and to assess damage throughout the season for making better management decisions;
Adjust predictive DD model after emergent trap collections;
Produce “MagLoid” newsletter with news clips and sampling plan ideas;
Submit first DD model to OSU “On-Line Phenology” website

March-June 2004:

Continue to monitor for CRF egg levels in above-ground Brassicas
Quantify importance of CM in above-ground Brassicas and develop egg-damage thresholds.
Design additional laminated, educational cards and monitoring handouts for Technical Transfer Workshop to Grower’s Employees (Monitoring Transfer workshop);
Write June newsletter issue of “MagLoid”; 5) Present the PEST Plan to growers before season begins.

July- Sept 2004:

Continue monitoring techniques;
Present Equipment Application Efficiency workshop;
Follow-up on growers who received the PEST Plan

Oct- Dec 2004:

Summarize data from 2003-2004 season and prepare reports;
Survey MagNet participants;
Present information at the OR Fresh Market Vegetable Growers annual meeting;
Present the PEST Plan results
Present all data on MagNet website,
Conduct workshop to review monitoring techniques, obtain project participant feedback, and teach CRF developmental stage ID and phenology;
Submit extension bulletin on CRF phenology and monitoring techniques.
Write journal article on “the PEST Plan” questionnaire.

Major Participants

Amy Dreves, an OSU-IPM specialist and Entomologist, is one of the principal investigators and the project coordinator. She will participate in project planning and evaluation as a member of and coordinator of the core group. She will oversee project management and on-farm research activities, and develop educational and evaluation materials and train project staff and growers.

Alexandra Stone, the state vegetable cropping systems specialist, is a principal investigator of the project. She will participate as a member of the core group and in data collection and analysis, and collaborate on development of educational and evaluation tools.

Dr. Tim Righetti, a Plant Nutrition and GIS specialist, will provide expertise in GPS and GIS techniques and spatial analysis for the spatial management study. He will help develop a user-friendly map and record management sheet and will help train growers to use the model.

Montecucco Farm: Montecucco Farm is a fresh market farm of 500 Acres in Canby, OR, specializing in root crop production (turnips, rutabaga, daikon). They have the resources and the commitment to collaboratively develop and document systems strategies for CRF management. They farm field clusters over a wide geographic area, so they are capable of implementing rotational management, row cover, and trap crop strategies. They will collaborate with project staff on design and implementation of spatial management and no-Lorsban spray experiments as well as conduct crop damage assessments and participate in CRF monitoring data collection.

Aurora Farms and C&S Farms: These two farms grow a diversity of fresh market vegetables. Aurora Farms specializes in radishes, while C&S Farms specializes in turnips and rutabagas. Both farms will conduct crop damage assessments, on-farm seed treatment trials, and participate in seasonal monitoring for CRF.

Stahlbush Farms, Haener Farms, and Winn Farms, all above-ground brassica growers, have agreed to join our team to help quantify the importance of CM and the use of chlorpyrifos in the above-ground crops.

Bob McReynolds: Bob is the OSU Extension Specialist for Fresh Market Vegetable Crops at the Northern Willamette Research and Extension Center in Aurora, OR. He has worked with the fresh market vegetable industry for many years, and has conducted many efficacy trials with IR-4. He will assist in furthering our knowledge-base in new chemistry evaluation and application techniques for use in an IPM-CRF management.

Dr. Glenn Fisher, the State Extension Entomologist, and Paul Jepson, Director of International Plant Protection Center has also agreed to be a participant, and will work in conjunction with Bob McReynolds to evaluate lower-risk pesticides and test efficiency of spray equipment. They will assist us in conducting a workshop for growers in this arena.

We will rely on degree-day modeling expertise from Dr. Paul Jepson, Professor and Director of OSU Integrated Plant Protection Center and Dr. Len Coop, Assistant Professor in Entomology
& IPPC both specializing in the areas of systems modeling and decision support systems.

Project Budget

Funding Request
Funding Requested	Other Funding	Total Funding
$39,989	$76,116	$116,105

Project Period: Jan 1, 2004 – Dec 31, 2004