Potato Leafhopper Resistant Alfalfa: The Potential for Improving Organic and Traditional Farming Systems

Final Report for ONE04-022

Project Type: Partnership
Funds awarded in 2004: $10,000.00
Projected End Date: 12/31/2005
Matching Non-Federal Funds: $47,070.00
Region: Northeast
State: Pennsylvania
Project Leader:
Marvin Hall
Penn State University
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Project Information

Summary:
  • Summary of Data.

    Potato Leafhopper Numbers:
    At all location x years, PLH numbers were monitored 68 times.
    54 times, there were no differences between varieties.
    9 times, the traditional variety had greater PLH numbers then the PLH resistant variety.
    5 times, the PLH resistant variety had greater PLH numbers than the traditional variety.
    PLH were chemically controlled in the traditional variety 9 times (100% of farms in 2004 and 40% of farms in 2005).

    Alfalfa Plant Density:
    Varieties were not different in plant density at any location 4 weeks after planting.
    At the conclusion of the study, the traditional variety had greater plant density than the PLH resistant variety at only 1 location. Otherwise there was no difference between varieties.

    Season-Total, Dry Matter Yield:
    9 locations x years, there were no differences between varieties.
    1 location x year, the traditional had greater DM yield then the PLH resistant variety.
    1 location x year, the PLH resistant had greater DM yield than the traditional variety.

    Economic Returns:
    Average economic returns:
    Traditional variety = $351.83 per acre
    PLH resistant variety = $352.42 per acre

    Conclusions.
    On average, the farms in this study had PLH numbers above the economic threshold less than once per year.
    Dry matter yield and economic return were nearly equal for each variety.
    Organic producers can utilize the potato leafhopper resistant alfalfa trait to avoid using PLH controlling chemicals and not sacrifice yield or economic return.

Introduction:

Alfalfa is the least expensive and consequently primary source of protein on dairy farms in the northeast U.S. However, Potato Leafhopper (PLH) infestations lower the yield, quality and persistence of alfalfa if they are not controlled. Traditionally, PLH control involves an insecticide application, which means that organic dairy producers suffer the full negative effects of PLH if they include alfalfa in their farming system. This can explain why there are only 2700 acres of organic alfalfa (0.3% of total alfalfa acres) in the northeast when there are more than 17,000 dairy cows (increasing at 27% each year) producing organic milk.

Insecticides that control PLH also kill beneficial or non-target insects (e.g. honey bees, lady-bird beetles, wasps that control alfalfa weevil). Killing these beneficial insects destroys the natural insect balance which can cause subsequent outbreaks of harmful crop insects in alfalfa and other crops.

In 1997, PLH-resistant alfalfa varieties were developed, using traditional breeding technology, and introduced to the market. The initial PLH-resistant varieties were about 35% resistant and current varieties have over 75% levels of resistance. It is not clear if these newer PLH-resistant varieties are able to improve the economic and environmental sustainability of dairy and hay crop farming systems.

Project Objectives:

Couple on-farm research that will quantify benefits of adopting PLH-resistant alfalfa varieties with outreach programs that demonstrate the potential for these new varieties to enhance the sustainability of their farming systems and reduce or eliminate the amount of insecticides applied annually in alfalfa production.

Cooperators

Click linked name(s) to expand
  • Craig Altemose
  • Mark Canon
  • Joe Hartle
  • Ron Hoover
  • Dan Kloos
  • Rob Kocher
  • Gary Micsky
  • Joe Paxton
  • Jan Pruss
  • Dan Ulmer

Research

Materials and methods:

PLH-resistant and PLH-susceptible varieties of alfalfa were planted on 6 farms located in Mercer (western) or Centre (central) counties in Pennsylvania. Producers provided field space (approximately 3 acres) for one replication of the two-treatment comparison. The three acres was divided and the PLH-resistant variety planted in half and the susceptible variety planted in the other half. Plantings was done in spring 2004 with the farmer’s drill or cultipacker seeder.

Throughout each growing season, each alfalfa variety at each farm was scouted and numbers of PLH, by the local Crop Management Association (CMA) personnel. The PLH-resistant variety was not be treated with insecticides. Chemical PLH control was applied to the PLH-susceptible variety when PLH threshold for economic damage had been reached.

The alfalfa was harvested by the producer-cooperator on his schedule. Yield was determined for each variety at each harvest.

Statistical analysis of forage yield, and PLH populations was conducted to determine possible differences between the alfalfa varieties. Financial benefits to the farming system, costs and net returns associated with crop production and management of varieties was determined and analyzed in partial budgets. Of greatest importance to organic dairy farmers and the community at large will be an assessment of the opportunity for alfalfa production without the use if insecticides. The analysis also includes estimates for regional and state-wide benefits from reducing insecticide usage if this new technology were to be widely adopted.

Research results and discussion:

Potato Leafhopper Numbers:
At all location x years, PLH numbers were monitored 68 times.
54 times, there were no differences between varieties.
9 times, the traditional variety had greater PLH numbers then the PLH resistant variety.
5 times, the PLH resistant variety had greater PLH numbers than the traditional variety.
PLH were chemically controlled in the traditional variety 9 times (100% of farms in 2004 and 40% of farms in 2005).

Alfalfa Plant Density:
Varieties were not different in plant density at any location 4 weeks after planting.
At the conclusion of the study, the traditional variety had greater plant density than the PLH resistant variety at only 1 location. Otherwise there was no difference between varieties.

Season-Total, Dry Matter Yield:
9 locations x years, there were no differences between varieties.
1 location x year, the traditional had greater DM yield then the PLH resistant variety.
1 location x year, the PLH resistant had greater DM yield than the traditional variety.

Economic Returns:
Average economic returns:
Traditional variety = $351.83 per acre
PLH resistant variety = $352.42 per acre

Research conclusions:

Conclusions.
On average, the farms in this study had PLH numbers above the economic threshold less than once per year.

Dry matter yield and economic return were nearly equal for each variety.

Organic producers can utilize the potato leafhopper resistant alfalfa trait to avoid using PLH controlling chemicals and not sacrifice yield or economic return.

These findings will be presented to over 2000 producers by April 2006.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary:

Education/outreach description:

Farmer field days were held in conjunction with this study in both 2004 and 2005 (± 40 participants).

Results from this study will be presented at farmer meetings during the 2006 winter. I have already gotten request to present these results at four meetings.

Results will be presented at the Pennsylvania Association of Sustainable Agriculture conference and the Pennsylvania Forage and Grassland Conference in February, 2006. These conferences generally have more than 1200 attendees.

Copies of these results will be distributed and made available to interested persons.

Project Outcomes

Project outcomes:

Economic Returns:
Average economic returns:
Traditional variety = $351.83 per acre
PLH resistant variety = $352.42 per acre

There appears to be no negative economic impact associated with the use of Potato Leafhopper Resistant alfalfa. This is important information for a organic producer.

Assessment of Project Approach and Areas of Further Study:

Areas needing additional study

Evaluation of PLH resistant varieties needs to be done on a longer time frame to determin if they persist as well as traditional varieties with chemical control of PLH.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.