Formulation and efficacy of Metarhizium anisopliae for wireworm management in potato and corn

Project Code: BPI07-080

Project Lead

Todd Kabaluk - Agriculture and Agri-Food Canada

Objective

Develop and characterize a new granular formulation of a local isolate of Metarhizium, and compare the efficacy of different Metarhizium-based control strategies against wireworms

Summary of Results

Background

Wireworms (Agriotes obscurus) induce damage to several crops, primarily by feeding on plant roots and tubers. These pests have been controlled until recently through the use of effective insecticides and by the residual activity of chlorinated hydrocarbon insecticides used during the middle part of the 20th century. However, in Canada almost all pesticides targeting wireworms are now unavailable due to low market potential, environmental concerns, and high risk assessments.

Metarhizium anisopliae strain LRC112 (hereafter referred to as LRC112), a fungal pathogen of insects, has shown promise as a microbial insecticide for wireworms. This strain has been shown to infect and kill wireworms under field conditions. However there remain constraints in moving this isolate toward commercialization: (i) environmental factors and targeting of the pest; and (ii) production and formulation of the isolate.

This project addressed both of these constraints by field testing a mycelial granule formulation of the LRC112 strain.

Approaches

The project was conducted at two locations (for each trial) in Agassiz, British Columbia in 2007. Mycelia granules of Metarhizium anisopliae were applied in field trials to test a range of formulations and application methods for reducing wireworm damage to potato and corn.

Test treatments were compared with industry standard (phorate) and untreated controls.The experimental design was a randomized complete block design with six blocks per trial. Results were analyzed by Analysis of Variance, with pre-treatment population levels of wireworms used as covariates in the analysis of potato and corn trials in one location, and levels of wireworms from guard rows of corn trials in one location also used as a covariate. Treatment differences were determined using Tukey's HSD (honest significant difference) test, α = 0.05.

Results

One of the two locations did not show any significant differences among the treatments on potato. The results from the second location showed that LRC112 drench provided control of wireworms. LRC112 drench performed better than the untreated control, with just 1.7 holes per tuber and 23% unmarketable potato yield, although not as well as the industry standard (phorate), which produced tubers with 0.7 holes per tuber and 10% unmarketable yield. All other treatments were not significantly different from their corresponding controls.

Field corn trial results showed that with the average percent emergence of 93%, LRC112 performed as well as clothianidin (97%) and Metarhizium F52 (93%). Data also showed that LRC112 increased the yield of field corn.

Conclusions

Results of this project indicate the potential of LRC112 for controlling of wireworms. Data showed that LRC 112 increased the yield of field corn. However, the use of LRC112 for wireworm control, remains inconclusive. To validate the efficacy of LRC112 in controlling wireworms in potato and corn, additional field trials will be needed. The successful development of LRC112 as a wireworm control will benefit the potato and corn industry a control product.

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