Resource Guide for Organic Insect and Disease ... - Cornell University

MATERIAL FACT SHEET
Streptomyces lydicus
168 Organic Resource Guide
MATERIAL NAME: Streptomyces lydicus
MATERIAL TYPE: Microbial
U.S EPA TOXICITY CATEGORY: IV, “Caution”
USDA-NOP
Considered non-synthetic, allowed. Preventive, cultural, mechanical, and physical methods
must be first choice for pest control, and conditions for use of a biological material must be
documented in the organic system plan (NOP 2000).
MATERIAL DESCRIPTION
Streptomyces lydicus is a ubiquitous, naturally occurring bacterium that is commonly found in
soil. The isolate WYEC 108 has been commercialized as an antifungal agent for greenhouse,
nursery, turf, and agricultural uses. It was isolated from a linseed plant growing in a soil that
exhibited natural suppression of root pathogens. The commercial product is a soluble powder
that contains S. lydicus spores and proprietary inert ingredients.
HOW IT WORKS
S. lydicus colonizes plant roots, competing with root pathogens for physical space and nutrients
exuded by the roots. Foliar applications result in colonization of aboveground plant parts.
It may act as a parasite of fungal plant pathogens. Other possible modes of action include
production of antibiotics, antifungal compounds, and enzymes that digest the cell walls of
fungi. Root colonization by S. lydicus is reported to increase plant vigor through the production
of siderophores, compounds that convert iron to a form more easily absorbed by plants. In
peas, it has been shown to colonize the surface of developing root nodules and improve the
vigor of nitrogen fixing Rhizobium bacteria in the nodules by increasing availability of iron (and
possibly other minerals) (Tokala et al. 2002).
TYPES OF PESTS IT CONTROLS
Product labels indicate soil drench and seed treatment applications for suppression of root
rot and damping-off pathogens, such as Fusarium, Rhizoctonia, Pythium, Phytophthora,
Phymatotrichum omnivorum (cotton root rot), Aphanomyces, Monosporascus, Armillaria,
Sclerotinia, Gaeumannomyces, Postia, Verticillium, and Geotrichum. Foliar applications are
intended to provide suppression or control of powdery and downy mildews, Botrytis, Monilinia,
Anthracnose, Mycosphaerella citri (greasy spot of citrus), Sclerotinia, Alternaria, and Erwinia.
FORMULATIONS AND APPLICATION GUIDELINES
Products are formulated as soluble powders and have a shelf life of at least one year.
Refrigeration may extend shelf life. They may be applied as soil treatments (e.g., drench, in
furrow), foliar applications, and bulb dusting treatments. Seed treatment may be applied as
dry hopper-box, mist, or slurry. Soil drenches may be applied through irrigation systems to
potting media or field soil. Irrigation systems connected to public water systems must be
equipped with a functional back-flow prevention system. Soil applications should begin at
an early stage of plant development to optimize root colonization. Foliar applications should
begin prior to the onset of disease and repeated every 7-14 days, depending on disease
pressure and how favorable environmental conditions are for disease progress. Spreaderstickers
are recommended for foliar applications. Actinovate products (currently the only OMRI
listed products that contain S. lydicus) are completely soluble and do not require tank agitation.
They can also be tank mixed with many fungicides, insecticides, and fertilizers unless otherwise
restricted. Actinovate is not compatible with sulfur (Fernandez et al. 2011).