Open AccessA Formulation of Trichoderma and Gliocladium to Reduce Damping-off Caused by Rhizoctonia solani and Saprophytic Growth of the Pathogen in Soilless Mix
Author(s) -
Jan Lewis,
Robert P. Larkin,
Deborah L. Rogers
Publication year - 1998
Publication title -
plant disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.663
H-Index - 108
eISSN - 1943-7692
pISSN - 0191-2917
DOI - 10.1094/pdis.1998.82.5.501
Subject(s) - rhizoctonia solani , biology , hypha , damping off , horticulture , pathogen , rhizoctonia , trichoderma , biomass (ecology) , hydroponics , botany , population , biological pest control , agronomy , microbiology and biotechnology , demography , sociology
Commercially manufactured cellulose granules (Biodac) were mixed with a sticker and fermentor-produced biomass of isolates of Trichoderma spp. and Gliocladium virens to produce a formulation in which chlamydospores in the biomass were “activated” with dilute acid. Activation resulted in the formation of young, actively growing hyphae of the biocontrol fungi within a 2- to 3-day period under no special aseptic conditions. Activated Biodac with biomass of isolates Gl-3, Gl-21, and Gl-32 of G. virens and isolate TRI-4 of T. hamatum applied to soilless mix at a rate of 1.5% (wt/wt) reduced damping-off of eggplant caused by Rhizoctonia solani (R-23) and resulted in stands comparable to that (88%) in noninfested soilless mix. Saprophytic growth of the pathogen was also reduced. The application of either of two activated Biodac formulations to provide the same amount (1.5% with 9.4 mg of biomass per g of Biodac or 0.2% with 75.0 mg of biomass per g of Biodac) reduced preemergence damping-off as well as saprophytic growth of R-23. Also, there was about a 10 3 -fold population increase of Gl-3 and TRI-4 in the soilless mix at the time of plant harvest compared with that provided to the soilless mix at the time of formulation addition. Activated Biodac of Gl-3 also reduced the spread of R-23 in soilless mix when the pathogen was applied at specific foci rather than evenly distributed. The inhibition of pathogen spread significantly reduced the postemergence damping-off of cucumber, eggplant, and pepper seedlings.