Journal of Plant Diseases and Protection (2009) 116, 200-207

A. Schmitt, E. Koch, D. Stephan, C. Kromphardt, M. Jahn, H.-J. Krauthausen, G. Forsberg, S. Werner, T. Amein and S.A.I. Wright (2009)
Evaluation of non-chemical seed treatment methods for the control of Phoma valerianellae on lamb`s lettuce seeds
Journal of Plant Diseases and Protection 116 (5), 200-207
Abstract: The aim of the present study was to identify seed treatment methods for eradicating Phoma valerianellae from lamb`s lettuce seeds in organic vegetable production. Using seeds naturally infested with the pathogen, the effect of three physical methods (hot water, aerated steam, electron treatment) and different agents of natural origin (micro-organisms, plant derived products, resistance inducers) was tested on moist filter paper, in seed trays under controlled conditions and in the field. In an initial screening, none of the tested putative resistance inducers prevented infection by P. valerianellae , while two out of seven formulated micro-organism preparations and six out of 16 experimental microbial strains were effective.
When selected agents and the three physical seed treatment methods were compared in blotter and seed tray tests, the physical methods were generally the most effective treatments, while the micro-organism treatments were clearly less efficacious. However, in field experiments with the same seed lots and the same treatments, a statistically significant increase in plant stand was not obtained with any of the treatments. Combinations of the three physical treatment methods with selected non-chemical agents did not perform better than the physical treatments alone. The most effective alternative seed treatments identified in the present study, aerated steam, hot water, electron treatment and thyme oil (0.1%), can be recommended for eradication of P. valerianellae from lamb`s lettuce seeds in organic farming. Because their efficacy was generally as high as that of the chemical fungicide Aatiram (active ingredient thiram), they are also potentially suited for use in conventional vegetable production.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Eckhard Koch, Annegret Schmitt, Gustaf Forsberg

Research topic(s) for pests/diseases/weeds:
control - general

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Stagonosporopsis valerianellae	Cornsalad (Valerianella)	Germany