Assessing Reduced-risk Insecticides and Refining Distribution and Phenology Models to Improve Management of Oriental Fruit Moth (OFM) in Apples and Peaches

Final Report for GNC08-094

Project Type: Graduate Student
Funds awarded in 2008: $10,000.00
Projected End Date: 12/31/2009
Grant Recipient: University of Illinois
Region: North Central
State: Illinois
Graduate Student:
Faculty Advisor:
Dr. Richard Weinzierl
University of Illinois
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Project Information

Summary:

The Oriental fruit moth (OFM), Grapholitha molesta, is a serious pest of peaches and apples, and populations of this pest in several areas are resistant to pyrethroids and organophosphates. We used SARE support for expanding evaluations of reduced-risk insecticides and expanding OFM and degree-day monitoring. Additionally, we requested support for grower participation in educational programs. Our overall goals were to develop and provide essential information in a timely manner so that small farmers involved in apple and peach production could profit from improved insect management practices.

To assess the effectiveness of reduced-risk insecticides, we worked with 8 apple and peach growers to evaluate rynaxypyr (Altacor), acetamiprid (Assail), novaluron (Rimon), and spinetoram (Delegate) used per EPA labels in plots of at least 2.5 acres. We also evaluated the effectiveness of these and other reduced-risk insecticides in small-plot trials at the University of Illinois Pomology Research Farm near Urbana, IL, and we conducted concentration-mortality bioassays to assess the baseline susceptibility of two OFM populations to reduced-risk and pyrethroid insecticides. To better understand the distribution and phenology of OFM in peach and apple orchards in Illinois, we worked with growers to use pheromone traps,temperature sensors, and degree-day software to monitor in-orchard temperatures and degree-day accumulations in comparison with the timing and relative density of OFM flights.

All of the reduced-risk insecticides tested (Altacor, Assail, Rimon, and Delegate) effectively controlled Oriental fruit moth in grower-applied trials in Illinois apple and peach orchards (including populations considered to be resistant to pyrethroid insecticides). These reduced-risk insecticides also effectively controlled Oriental fruit moth and codling moth in small-plot trials at the University of Illinois orchard near Urbana, IL, but only Assail adequately controlled concurrent infestations of apple maggot, a key pest in apples in the northern Midwest. Oriental fruit moths were captured in pheromone traps at orchards as far north as the area surrounding Peoria, IL, but not at locations near Rockford (near the Wisconsin border). Captures in pheromone traps at locations north of Urbana, IL, were too sporadic to allow comparisons of flight timing with published degree-day models. At two orchards where mating disruption was used (in far southern IL and in western IL), no Oriental fruit moths were captured in pheromone traps – evidence of successful disruption of mating and control within those orchards. Counts of moths from pheromone traps in other orchards have been added to a multi-year database to validate/refine degree-day models of seasonal patterns of Oriental fruit moth occurrence. Concurrent work established baseline dose-response relationships that describe the toxicity of rynaxypyr, acetamiprid, spinetoram, spinosad, novaluron, esfenvalerate, and lambda-cyhalothrin to susceptible populations of Oriental fruit moth; these results provide a basis for future monitoring of insecticide resistance in this pest.

Gross incomes for fresh-market sales of peaches can exceed $18,000 per acre (300 bushels per acre X $60.00 per bushel). In areas where pyrethroid resistance led to culling nearly 20 percent of the crop in 2005 and 2006, losses were estimated at greater than $3,000 per acre. The reduced-risk insecticides evaluated in this research reduced losses to less than 1 percent – therefore reducing monetary losses by $2,970 per acre.

Introduction:

Specialty crops such as fruits and vegetables offer opportunities for diversification and increased profitability. Fruit and vegetable producers contribute to rural and urban economies and quality of life by providing jobs, local produce, and direct contact between producers and consumers at on-farm and farmers markets. However, fruit and vegetable production often involves significant use of pesticides to prevent scarring and contamination of produce. Negative impacts of pesticides can include unwanted residues on foods, environmental contamination, and development of pesticide resistance. To reap the broad benefits of fruit and vegetable production on diversified farms and minimize negative impacts of pesticide use, effective, reduced-risk pest management alternatives must be developed and used.

The Oriental fruit moth (OFM), Grapholitha molesta, has been a serious pest of peaches and other fruit crops since its introduction into North America in 1916. In the 1990s, infestations in apples increased markedly in the eastern US, and severe infestations were reported from apples in IL in 2006. OFM populations in southwestern IL and elsewhere are resistant to pyrethroids and organophosphates. Recent increased losses to OFM threaten the viability of apple and peach production in southern and southwestern IL and the lower Midwest.

To contribute sustainable peach and apple production via improved pest management, our overall research on OFM has two broad objectives:
1) Describe baseline susceptibility of OFM populations to key insecticides, including newly available reduced-risk and OMRI insecticides; identify any cross-resistance potential for the reduced-risk insecticides; and evaluate the effectiveness of reduced-risk insecticides in field trials.
2) Refine our knowledge of the geographic distribution and relative density of OFM in IL and its seasonal occurrence in relation to degree-day accumulations (phenology models) to better identify the need for and timing of management practices.

We requested SARE support for specific aspects of these objectives: 1) expanding evaluations of reduced-risk insecticides
2) expanding OFM and degree-day monitoring.

Additionally, we requested support for grower participation in educational programs. Our overall goals are to develop and provide essential information in a timely manner so that small farmers involved in apple and peach production can profit from improved insect management practices.

Project Objectives:

Our immediate and short-term objectives for the 2009 season were:

University of Illinois personnel and 8 peach and apple growers will
1) complete on-farm, large-plot trials and small-plot trials to assess the effectiveness of reduced-risk insecticides for management of OFM and other key pests in peach and apple orchards
2) use available monitoring methods to improve models of the distribution and phenology of OFM in peach and apple orchards to allow more efficient management.

Our intermediate-term objectives for 2010 – 2012 remain in progress (beyond the funding period for this grant):

Aided by University of Illinois personnel, >50 peach and apple growers will (1) choose insecticides and other management practices that reduce environmental and human health risks while reducing losses to key pests and improving profitability, and (2) develop greater confidence in and reliance on pheromone traps and phenology models for pest management decisions, reducing unnecessary insecticide applications.

Over the long term (3 to 5 years):

This project was established to contribute to broader advances so that specialty crop growers use and share pest monitoring and modeling techniques to improve pest management and reduce reliance on excessive insecticide applications.

Cooperators

Click linked name(s) to expand
  • Raoul Bergersen
  • Kurt Christ
  • Sara Lipe
  • Lori Murray
  • Tom Ringhausen
  • Tom Schwartz
  • Wayne Sirles
  • Craig Tanner
  • Rick Weinzierl

Research

Materials and methods:

To assess the effectiveness of reduced-risk insecticides …
1) We worked with 8 apple and peach growers in 2009 to evaluate rynaxypyr (Altacor), acetamiprid (Assail), novaluron (Rimon), and spinetoram (Delegate) used per EPA labels in plots of at least 2.5 acres. Applications were timed according to pheromone trap and degree-day information for each location, and three successive sprays of the candidate insecticide were applied at approximately 14-day intervals. Approximately 2 weeks after the final application of each insecticide, University of Illinois personnel assessed crop injury caused by OFM and other pests (including direct pests such as codling moth, apple maggot, stink bug/plant bug, leafrollers etc., and indirect pests such as aphids, spider mites, leafminers, etc.).
2) We also evaluated the effectiveness of reduced-risk insecticides in small-plot trials at the University of Illinois Pomology Research Farm near Urbana, IL.
3) In conjunction with these field projects, we conducted concentration-mortality bioassays to assess the baseline susceptibility of two OFM populations to reduced-risk and pyrethroid insecticides.

To better understand the distribution and phenology of OFM in peach and apple orchards in Illinois, we worked with the 8 growers identified on the main page of this project to use pheromone traps and Spectrum Watchdog temperature sensors and degree-day software from March through September of 2009 to monitor in-orchard temperatures and degree-day accumulations in comparison with the timing and relative density of OFM flights.

Research results and discussion:

• All of the reduced-risk insecticides tested (Altacor, Assail, Rimon, and Delegate) effectively controlled Oriental fruit moth in grower-applied trials in Illinois apple and peach orchards (including populations considered to be resistant to pyrethroid insecticides).
• These reduced-risk insecticides also effectively controlled Oriental fruit moth and codling moth in small-plot trials at the University of Illinois orchard near Urbana, IL, but only Assail adequately controlled concurrent infestations of apple maggot, a key pest in apples in the northern Midwest.
• Oriental fruit moths were captured in pheromone traps at orchards as far north as the area surrounding Peoria, IL, but not at locations near Rockford (near the Wisconsin border. Captures in pheromone traps at locations north of Urbana, IL, were too sporadic to allow comparisons of flight timing with published degree-day models. At two orchards where mating disruption was used (in far southern IL and in western IL), no Oriental fruit moths were captured in pheromone traps – evidence of successful disruption of mating and control within those orchards. Counts of moths from pheromone traps in other orchards have been added to a multi-year database to validate/refine degree-day models of seasonal patterns of Oriental fruit moth occurrence.
• Concurrent work related to these SARE-funded efforts established baseline dose-response relationships that describe the toxicity of rynaxypyr, acetamiprid, spinetoram, spinosad, novaluron, esfenvalerate, and lambda-cyhalothrin to susceptible populations of Oriental fruit moth; these results provide a basis for future monitoring of insecticide resistance in this pest.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Publications:

Jones, M.M. 2010. Susceptibility of Oriental fruit moth, Grapholita molesta (Busck), to selected insecticides and mixtures. Ph.D. Thesis, University of Illinois, Urbana-Champaign. 118 pp.

Jones, M.M., J.L. Robertson, and R.A. Weinzierl. In Press. Susceptibility of Oriental Fruit Moth (Lepidoptera: Tortricidae) Larvae to Selected Reduced-Risk Insecticides. J. Econ. Entomol. (Accepted May 3, 2010.)

Weinzierl, R., M. Jones, J. Funk, and J. Kindhart. Evaluations of reduced-risk insecticides in apples and peaches in Illinois, 2009-2010. In press. Pp. TBD, in: 14th Annual (2010) Illinois Fruit and Vegetable Research Report, University of Illinois at Urbana-Champaign.

Outreach:

Findings from 2009 SARE-supported activities were reported at the 2010 Illinois Specialty Crops, Agritourism, and Organics Conference, the 2010 Southern Illinois Fruit School, the 2010 Southwestern Illinois Fruit School, and the 2010 State Line (IL-WI)Fruit and Vegetable Conference (total attendance ~250 growers). Recommendations also were incorporated into the 2010 Midwest Tree Fruit Spray Guide and the Illinois Fruit and Vegetable News (newsletter).

Project Outcomes

Project outcomes:

Growers throughout Illinois have necessary information to adopt the use of reduced-risk insecticides to control Oriental fruit moth and codling moth in peaches and apples. Surveys will be conducted in January, 2011, to measure adoption. See the text below on the economic impacts of pest management decisions in peaches.

Economic Analysis

No formal economic analysis of the benefits of improved management of Oriental fruit moth was done. However, gross incomes for fresh-market sales of peaches can exceed $18,000 per acre (300 bushels per acre X $60.00 per bushel). In areas where pyrethroid resistance led to culling nearly 20 percent of the crop in 2005 and 2006, losses were estimated at greater than $3,000 per acre. The reduced-risk insecticides evaluated in this research reduced losses to less than 1 percent – therefore reducing monetary losses by $2,970 per acre. The cost of 6 applications of these products (in rotations to forestall resistance and according to label rates and preharvest intervals to avoid excessive residues) is estimated at less than $240 per acre to prevent losses that can exceed the average of $3,000 per acre. Using traps to monitor flights of Oriental fruit moth (as demonstrated) can guide the timing of insecticide applications so that they are most effective and not used unnecessarily.

Farmer Adoption

Growers involved in the SARE project all have adopted the use of alternative / reduced risk insecticides for management of Oriental fruit moth and codling moth. They have shared their observations with other growers at the outreach events listed above. Informal surveys of growers who attended extension programs in 2010 indicated widespread intentions to switch to using the reduced-risk insecticides evaluated in this project (and similar reduced-risk products). Growers who attend outreach programs in January and February, 2011, will be surveyed to determine the adoption of reduced-risk insecticides in 2010 and plans for 2011.

Recommendations:

Areas needing additional study

Management options for Oriental fruit moth and codling moth are reasonably well understood, but the integration of progressive management practices aimed at these pests (reduced risk insecticides and mating disruption) with practices needed for other pests still needs to be refined. This need will be intensified if/when the brown marmorated stink bug reaches Midwestern production areas. Its presence is likely to require intensive use of insecticides that will disrupt integrated programs that researchers and growers have tailored to meet the needs of individual orchards.

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.