Integration of Microbial Pesticides in Pome-Fruit Production in the Pacific Northwest

Integration of Microbial Pesticides in Pome-Fruit Production in the Pacific Northwest

Summary

Research with foam and gel formulations in mulch and on tree trunks demonstrated improvement in larvicidal activity of two species of nematodes. The formulations maintained moisture enabling survival of the infective stages and higher mortality of larvae. Field demonstrations of a strain of CpGV reported to overcome moth resistance was as effective for control the commercial product. No resistance in codling moth has been detected. Fumigation of adult and larval codling moth with volatile compounds produced by a biofumigant fungus resulted in high mortality of all stages. Our outreach program has significantly increased owing to Western SARE funding.

Objectives/Performance Targets

1. Monitor the effectiveness of operational spray programs including microbials (chiefly CM virus) in apple and pear orchards. This monitoring was done on two orchards, one organic and one treated with mixed chemicals and biopesticides. The organic orchard has less effective control using the codling moth virus than it had in the previous year. Determined by pheromone trapping and apple damage.
2. Conduct research components as part of (1)
Evaluate CpGV as a replacement for one or more sprays with chemical pesticides. This work is planned for 2010. Obtain baseline data of efficacy of commercial formulations of CpGV to facilitate resistance monitoring among regional pest populations. This research was conducted at the USDA experimental farm. At operational and half rate dosage, the Cyd-X formulation consistently performed as in previous years.
3. Conduct demonstration trials at our experimental orchard near Moxee. Demonstration of Cyd-X was compared with a new strain in multiply replicated tests. Both strains performed equally well.
4. Improve the stability and effectiveness of CpGV and spinosad under operational conditions through formulation (lignin- and particle-film based adjuvants). In laboratory studies using a solar simulator lignin formulation provided significant protection from UV radiation. In the field the protection of the virus was reduced considerably.
5. Disseminate relevant information such as optimal application strategies or issues of concern regarding secondary pests through specified outreach activities. In addition to publications, 7 presentations were made at grower meetings, field day and scientific meetings.

Accomplishments/Milestones

Research Accomplishments in the development of codling moth granulovirus (CpGV) entomopathogenic nematodes (EPNs) for control of two larval stages of codling moth and a biofumigant fungus for control of codling moth in post harvest apple.

Evaluation of 3 new formulations of EPNs was conducted in the fall of 2008 and spring and fall of 2009. A foam formulation consisting of wood flour and adjuvants was applied immediately after application of EPNs for control of the overwintering stage of the moth (cocooned larvae). The foam maintained moisture enabling survival of the infective stages (IJs) of Steinernema carpocapsae and S. feltiae permitting greater possibility of encountering cocooned larvae under bark and in leaf litter. Larval mortality was increased significantly with the foam formulation compared to aqueous suspensions of IJs. Cooler fall temperatures enabled greater survival of IJs and increased mortality of codling moth. A gel formulation (a biodegradable flame retardant) was also evaluated and significantly survival of the EPM and increased mortality in codling moth larvae in 2009 spring and fall tests. A formulation consisting of infected wax moth larvae provided effective control in laboratory tests but failed to produce significant mortality in field tests against cocooned larvae under mulch.

In late 2008 we concluded research on storage and formulation of the codling moth granulovirus. CpGV retained 100% of the original larvicidal activity for over two years when stored at 2°C. CpGV encapsulated in lignin persisted slightly longer under ultra violate radiation than unprotected virus. Research on dry formulations of codling moth granulovirus (CpGV) produced by BioTepp, Inc. was concluded in 2009. Mortality produced by the dry formulation was inferior to liquid formulations currently on the market. Comprehensive reviews on CpGV and use of microbial control in integrated pest management of orchard pests were published in 2008 and widely distributed to scientists, organic growers and crop consultants. Yakima County, State of Washington and Washington State University extension personnel have assisted in lining up orchard demonstrations for 2010. Concentrated formulations from Andermatt Labs (the main supplier of Certis USA) were compared with the original Certis formulation (Cyd-X). No substantial difference in efficacy was noted. However, another CpGV strain from Andermatt the virus is reported to overcome codling moth resistance to the Mexican strain of CpGV used in all commercial products. Our bioassay results and extensive field testing indicated that the new strain is efficacious as the original Cyd-X formulation. Resistance is widely reported in European organic orchards where the virus has been used for 15-20 years. Monitoring of two organic orchards revealed that CpGV was less effective as in previous years. It is doubtful that this is due to resistance. More intense monitoring will be conducted in 2010.

The endophytic fungus, Muscodor albus, produces volatile compounds (VOCs) that are biocidal for several pest organisms including plant pathogens and insect pests. The objectives of our research were to determine the effects of M. albus VOCs on codling moth adults, neonate larvae, larvae in infested apples, and diapausing cocooned larvae in simulated storage conditions. Fumigation of adult codling moth with VOCs produced by M. albus for 3 d and incubating in fresh air for 24 h at 25°C resulted in 81% corrected mortality. Four- and five-day exposures resulted in higher mortality (84 and 100%, respectively) but control mortality was also high due to the short life span of the moths. Exposure of neonate larvae to VOCs for 3 d on apples and incubating for 7 d resulted in 86% corrected mortality. Treated larvae were predominantly 1st instars, while 85% of control larvae developed to 2nd and 3rd instars. Exposure of apples that had been infested for 5 d, fumigated with M. albus VOCs for 3 d and incubated as above resulted in 71% corrected larval mortality. Exposure of diapausing cocooned codling moth larvae to VOCs for 7 or 14 d resulted in 31 and 100% mortality, respectively, with negligible control mortality. Our data on treatment of several stages of codling moth with M. albus VOCs indicate that the fungus could provide an alternative to broad spectrum chemical fumigants for codling moth control in storage and contribute to the systems approach to achieve quarantine security of exported apples.

Outreach accomplishments: Our outreach program has significantly increased in large part due to the objectives of the Western SARE grant. The overall goal is to disseminate information generated from our research to orchardists, farm managers and crop consultants. The presentations and publications listed below for late 2008-2009 have resulted in substantial transfer of microbial control technology to these groups. Another objective is to recruit and train young scientists, especially from under represented minorities (Native Americans, Hispanics and women). Training this year has included the hiring of a recently graduated woman and familiarizing her with the production, quantification, bioassay and field assessment of insect pathogens that can be used for control of orchard pest insects. She is currently enrolled in a teaching credential program at Central Washington University and has spoken of the potential of transferring her skills learned in our lab to students in the near future. She will work with us part-time until obtaining her teaching credential. We also employed an under-graduate Hispanic male for our summer intern program. We have also trained a college educated Hispanic male in the laboratory and field technology. He also functions as our link with Hispanic workers and orchardists during presentation of workshops and field demonstrations. Part of our outreach is through the TechReach project for early (middle school) students at risk. I have attended two meetings of the American Indian Society of Engineering and Science (AISES) as a representative of the USDA Agricultural Research Service to encourage recruitment and diversity within the USDA.

Outreach presentations. Seven presentations were made in late 2008 and 2009 on various topics in microbial control and integrated pest management of orchard pests at grower and scientific society meetings.

Impacts and Contributions/Outcomes

Development of new formulations of entomopathogenic nematodes (EPNs) for control of overwintering larval stage of codling moth and a new strain of the codling moth granulovirus.

Impact: New formulations of EPNs will enable more practical use by orchardists. Availability of codling moth virus that can overcome resistance of the moth will be in place should resistance develop in the USA as it has in Europe.

Contribution: Development of a new formulation of EPNs that provides a practical means of maintaining moisture, thereby allowing longer survival and greater infectivity of EPNs. Successful evaluation of a new strain of codling moth virus.

Outcome: some orchardists are interested but have not yet implemented EPNs in their orchards. The increase in efficacy will provide incentive to use EPNs as part of integrated management of codling moth. The virus is not yet commercially available. Our research results will enable its more rapid registration when it is produced on a commercial scale. This technology was transferred to growers and practitioners at several meetings and one field day.

Collaborators: