Many growers utilize RootShield® PLUS+ for the benefits it provides at planting. But did you know RootShield PLUS+ can be applied multiple times through a crop cycle to ensure root protection and promote plant health?
What is RootShield PLUS+?
RootShield PLUS+ is a proven bio-fungicide that contains two species of Trichoderma (T. harzianum strain T-22 and T. virens strain G-41). These two strains work together to effectively control major root diseases (Cylindrocladium, Fusarium, Pythium, Phytophthora, Rhizoctonia and Thielaviopsis) but they bring so much more.
RootShield PLUS+ has four primary modes of action:
(1) Competitive exclusion: the Trichoderma species outcompete root pathogens for space and resources on the root surface, thus obstructing their access to the roots.
(2) Antagonism: As the Trichoderma grow, they produce enzymes and other metabolites that inhibit pathogen growth.
(3) Induce a plant’s natural defenses
(4) Mycoparasitism: Trichoderma will grow around mycelial strands of pathogens and produce enzymes which disintegrate the invading pathogen’s cell walls.
When RootShield® PLUS+ is applied to growing media, the Trichoderma spores germinate within 16 – 24 hours. The emerging mycelia grow around the plant’s roots, occupying space in the rhizosphere. After 24 hours the Trichoderma cannot be dislodged from the roots. In the growing medium, RootShield can tolerate a wide pH range (4 – 8) and grows at temperatures from 48° to 97° F.
When to apply RootShield® PLUS+ for extended protection?
A RootShield PLUS+ application is effective for approximately 8 to 12 weeks, depending on growing conditions. Over time, due to microbial competition, the Trichoderma concentration slowly declines to levels that are not optimal for root protection. Consequently, we recommend re-application of the biofungicide to maintain levels of Trichoderma in the growing medium.
When crops or liners are transplanted into larger containers, the media should be treated with RootShield PLUS+ WP (6-8 oz per 100 gallons), or the granular formulation can be pre-incorporated into the medium (1.5 lbs/yd3). This ensures that sufficient Trichoderma spores will be available to colonize and protect the new roots as they grow.
If a crop is in its final container size and was treated with RootShield PLUS+ prior, an additional application can be made 8 to 12 weeks later. This can be applied at a half rate (3-4 oz per 100 gallons) to boost Trichoderma levels on the plant’s root system and effectively prevent root disease for an additional 8 to 12 weeks. This re-application interval can be repeated throughout the crop cycle.
Despite RootShield’s ability to parasitize pathogenic fungi, it is not considered an eradication or rescue treatment. Its efficacy is greatly enhanced if it is administered early, ideally during propagation and prior to root infection. Applications of RootShield PLUS+ through the production cycle will ensure that adequate levels of Trichoderma are maintained in the growing medium, providing weeks of protection against detrimental soilborne pathogens.