ARS | Publication request: Greenhouse and Field Evaluation of the Natural Saponin CAY-1, for Control of Several Strawberry Diseases

Submitted to: International Journal of Fruit Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 14, 2009
Publication Date: September 29, 2009
Citation: Abril, M., Curry, K.J., Smith, B.J., De Lucca Ii, A.J., Boue, S.M., Wedge, D.E. 2009. Greenhouse and Field Evaluation of the Natural Saponin CAY-1, for Control of Several Strawberry Diseases. International Journal of Fruit Science. 9:3,211-220.

Interpretive Summary: Diseases often cause severe losses to strawberry growers. Most growers depend on chemical fungicides for control of these diseases, but the number of effective fungicides has been reduced due to loss of registration of some materials and the loss of efficacy of some fungicides due to the development of resistance in the pathogen population. Fungicides with different modes of action and reduced risk to the human population are needed to provide good disease control. We evaluated the natural product based fungicide, CAY-1, for its potential use on strawberries. In greenhouse trails, CAY-1 provided protection against infection by the anthracnose pathogen when applied 24 hours before inoculation by preventing germination of the fungal spore. However, CAY-1 did cause injury to the leaves when applied at higher concentrations. In field trials strawberry plots treated with CAY-1 exhibited as much disease as untreated plots. The higher levels of disease on the CAY-1 plots were probably due to injury of the fruit and foliage by CAY-1. Improvements in the formulation of CAY-1 might prevent this injury and result in better disease control. This information will be useful to other scientists developing natural product based fungicides and to extension personnel making disease control recommendations to strawberry growers.

Technical Abstract: The steroidal saponin from cayenne pepper, CAY-1, was tested as a potential fungicide in detached leaf assays and field trials. Efficacy of CAY-1 against strawberry anthracnose was compared to the commercial fungicide azoxystrobin. Both fungicides prevented anthracnose leaf lesions when applied to the host 24 hr prior to inoculation with Colletotrichum fragariae, but neither prevented lesion development when applied 24 hr after inoculation. CAY-1 reduced the growth of several fungal pathogens in laboratory assays and prevented anthracnose development in detached leaf assays, but it did not control foliar or fruit rot diseases of strawberry in field trials.