Stable fungal blastospores and methods for their production, stabilization and use
Inventors
Jackson, Mark A. • Moura, Mascarin, Gabriel
Assignees
Empres A Brasiliera De Pesquisa Agropecuaria • Empresa Brasileira de Pesquisa Agropecuaria EMBRAPA • US Department of Agriculture USDA
Publication Number
US-10889798-B2
Publication Date
2021-01-12
Expiration Date
2035-09-15
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Abstract
Described herein is a method for blastospore-based insect control products of entomopathogenic fungi including either B. bassiana or I. fumosorosea that produces high concentrations of stable, effective spores by identifying nutritional and environmental conditions required for the rapid production of high concentrations of a stable and infective yeast-like blastospore composition.
Core Innovation
The invention provides methods and compositions for producing desiccation-tolerant, shelf-stable blastospores (vegetative cells) of entomopathogenic fungi including Beauveria bassiana and Isaria fumosorosea. This is achieved by inoculating liquid culture media comprising a carbon source and a nitrogen source with fungal propagules, incubating under culture conditions with dissolved oxygen levels above zero and osmotic pressure greater than 0.5 MPa, followed by harvesting and drying the blastospores to produce stable, infective blastospores.
The invention addresses the problem of controlling arthropod pests in agriculture using fungal biocontrol agents. Traditional chemical insecticides have disadvantages such as pest resistance, non-selectivity affecting beneficial species, and environmental/health concerns. While fungal entomopathogens show promise, blastospores produced by liquid culture have lacked desiccation tolerance and shelf life, hindering their commercial use. The present invention solves the technical challenges by defining nutritional and environmental parameters that enable rapid production of stable blastospores effective for pest control.
Claims Coverage
The patent contains independent claims covering the insecticidal composition and methods for producing and using desiccation-tolerant blastospores of Beauveria bassiana.
Production of desiccation-tolerant blastospores under specified liquid culture conditions
The method comprises inoculating a liquid culture medium containing a carbon source and a nitrogen source (at least 1.5% w/v) with Beauveria bassiana propagules, incubating under liquid culture conditions providing dissolved oxygen above zero and osmotic pressure over 0.5 MPa, incubating for sufficient time to produce blastospores, collecting and drying them to produce desiccation-tolerant blastospores with greater than 60% germination after over six months storage at 4° C.
Insecticidal composition containing desiccation-tolerant blastospores in airtight packaging
An insecticidal composition comprising an agronomically acceptable carrier and desiccation-tolerant blastospores of Beauveria bassiana with over 60% germination after six months storage at 4° C., wherein the carrier and blastospores are contained in air-tight packaging and the blastospores are produced by liquid culture as described above.
Incorporation of oxygen and moisture scavengers in the composition
The insecticidal composition can additionally include oxygen scavenging compounds, moisture scavenging compounds, or combinations thereof to improve storage stability.
Method for insect control by applying effective amount of composition
A method of insect control comprising applying an insecticidally effective amount of the composition described above to the site of affected insects, optionally specifying carbon source as glucose and nitrogen source as cottonseed flour or hydrolyzed casein, with the site being an agricultural crop.
The independent claims cover a method for producing stable Beauveria bassiana blastospores under defined liquid culture conditions, an insecticidal composition containing these blastospores in sealed packaging, and methods for using the composition for insect control, including the use of oxygen and moisture scavengers to enhance stability.
Stated Advantages
The invention enables rapid production of high concentrations of desiccation-tolerant, shelf-stable blastospores suitable for commercial use as biocontrol agents.
The produced blastospores have greater infectivity and speed of kill against target pests compared to aerial conidia.
Use of inexpensive nitrogen sources such as cottonseed flour reduces production costs.
The methods provide improved storage stability of blastospores, achieving viability of greater than 60% after prolonged storage at 4°C or even at 28°C with proper packaging and scavengers.
Documented Applications
Control of arthropod pests in plant-based agriculture using blastospore-based insecticidal compositions containing Beauveria bassiana or Isaria fumosorosea.
Treatment of various agricultural crops and sites infested with insect pests such as whiteflies, rootworms, termites, aphids, beetles, and other economically important insects.
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