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

the biocontrol activity exhibited by these species (Harman 2011). Other benefits of root
colonization by Trichoderma and related organisms include enhanced plant resistance to stress,
such as drought or salt buildup, and enhanced nitrogen use efficiency (Harman 2011).
Biocontrol and plant growth enhancement effects are specific to pathogen, beneficial and
strain species, and plant cultivar. Beneficial effects in one pathogen/beneficial/cultivar system
should not be expected in another system. In one study, tomato plants receiving Trichoderma
harzianum soil treatments showed increased disease levels of bacterial speck, possibly as a
result of a larger canopy that enhanced the microclimate for the disease. (Lange & Smart 2004).
In other studies, tomato plants receiving a Trichoderma harzianum soil treatment showed
reduced levels of the fungal disease early blight (Seaman 2003).
Some strains of T. harzianum are pathogenic on mushrooms, causing serious economic losses
in commercial production.
TYPES OF PESTS IT CONTROLS
Most early work on Trichoderma focused on protection from root or tuber pathogens, such as
Pythium, Fusarium, and Rhizoctonia, by treating seed, soil, or potting mix with formulations
of fungal spores. As other mechanisms for protection from pathogens were discovered,
foliar applications were tested for control of aboveground pathogens. As more is learned
about the induced resistance response in plants, researchers are also looking at the control of
aboveground pathogens by soil-applied treatments.
FORMULATIONS AND APPLICATION GUIDELINES
Spores of Trichoderma and related species are generally formulated in one of two ways: 1) as
granules to be mixed with potting media or for in-furrow treatments, or 2) wettable powders
to be mixed with water and used as potting media or soil drenches, in-furrow applications,
seed treatments, or in irrigation water. Some products are labeled for foliar applications
on ornamentals, but not currently for food crops. Optimizing beneficial effects depends on
thorough colonization of the root system, so application at an early stage of plant development
is important. These products will not be effective as “rescue” treatments in situations where
inoculum or disease levels are high, and they work best as part of an overall integrated pest
management strategy. Because they are living organisms, products have a shelf life of 6-12
months, depending on temperature, with longer shelf life at lower storage temperatures.
OMRI LISTED PRODUCTS
BIO-TAM (AgraQuest, Inc.)
Plant Shield® HC Biological Fungicide (BioWorks, Inc.)
RootShield® Granules (BioWorks, Inc.)
RootShield® Home & GardenBiological Fungicide (BioWorks, Inc.)
SoilGard® 12 G Microbial Fungicide ( Certis)
T-22 HC Biological Fungicide (BioWorks, Inc.)
T-22 Planter Box Biological Fungicide (BioWorks, Inc.)
Tenet WP (Isagro USA)
References to OMRI listed products in this Guide are based on the 2012 edition of the OMRI
Product List. Please consult www.omri.org for changes and updates in the brand name product
listings.” after product list.
REENTRY INTERVAL (REI) AND PRE-HARVEST INTERVAL
When used in enclosed environments, such as glasshouses and greenhouses, reentry interval is
0 hours. Such treatments include soil application via soil drench,
in-furrow spray, transplant starter solution, dip, soak, or chemigation.
For field applications: Keep unprotected persons out of treated areas until sprays have dried or
dusts have settled. Pre-harvest interval is 0 days.
Organic Resource Guide 181