Fall application of Metarhizium brunneum microsclerotia as soil applied granules to reduce summer emergence of walnut husk maggot adults

Authors: Behle, Robert

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/25/2020
Publication Date: 11/25/2020
Citation: Behle, R.W. 2020. Fall application of Metarhizium brunneum microsclerotia as soil applied granules to reduce summer emergence of walnut husk maggot adults. Meeting Abstract. [abstract].

Interpretive Summary:

Technical Abstract: Rhagoletis fruit flies damage many fruit and nut crops and the Sauvis group in this genus includes pests of walnuts in the Americas. The walnut husk maggot, Rhagoletis sauvis (Loew) (Diptera: Tephritidae), causes damage to walnuts when maggots feed inside the husk around developing nuts. The adult stage is most susceptible to chemical control by applications of insecticides during summer months, before oviposition in walnut husks. To evaluate a biological control strategy, granules laced with microsclerotia of the entomopathogenic fungi Metarhizium brunneum F52 were applied to the soil during September targeting mature larvae as they leave the nut to pupate in the soil. The treatment was evaluated for pest control based on adult emergence during the following summer. September applications generally reduced the number of flies emerging from treated plots when compared with untreated plots. For both years, Metarhizium granules reduced subsequent fly emergence nearly 35% and may contribute to an integrated approach for control of this pest and its close relatives.