Composition of entomopathogenic fungus and method of production and application for insect control
Inventors
Jackson, Mark A. • Jaronski, Stefan T.
Assignees
US Department of Agriculture USDA
Publication Number
US-11058120-B2
Publication Date
2021-07-13
Expiration Date
2027-09-13
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Abstract
Microsclerotia of entomopathogenic fungi, including Metarhizium species, Beauveria species, and Lecanicillium species, may be produced. These microsclerotia are effective for the control of a wide variety of insect pests, particularly soil-dwelling insect pests.
Core Innovation
The invention relates to the formation of microsclerotial propagules by entomopathogenic fungi and their use for the control of insects. Microsclerotia of entomopathogenic fungi including Metarhizium species, Beauveria species, and Lecanicillium species are produced in submerged liquid culture. These microsclerotia are desiccation tolerant, exhibit excellent shelf-life at room and refrigerated temperatures, and can be processed into formulation sizes compatible with conventional granular pesticide applicators.
The microsclerotia sporulate profusely upon rehydration in environments such as soil, producing large numbers of insect-infectious conidia. They may exhibit comparable or higher levels and rates of infectivity against insect pests compared to conventional conidia-based granular formulations. Methods for producing these microsclerotia in high yield, their recovery, and formulation into commercial insect control products are described.
The background problem addressed is the limited persistence, physical characteristics, shelf-life, and high production costs associated with conventional entomopathogenic fungal formulations such as conidia-coated carriers, mycelial pellets, or blastospores. These limitations have restricted practical application in agricultural and soil pest control. The invention solves these problems by providing stable, desiccation tolerant microsclerotia which have superior shelf-life, production efficiency, and compatibility with conventional application equipment, enabling effective biological control of soil-dwelling and other insect pests.
Claims Coverage
The patent contains one independent method claim directed to producing desiccation tolerant fungal microsclerotia and related methods for insect control. The following are the main inventive features of these claims.
Production of desiccation tolerant fungal microsclerotia
A method comprising inoculating a liquid culture medium containing specific concentrations of a carbon source (>20 grams/liter) and a nitrogen source (between 8.1 and 50 grams/liter) with fungal propagules of entomopathogenic fungi from Metarhizium, Beauveria, or Lecanicillium species; incubating for sufficient time to produce microsclerotia; and collecting the resulting desiccation tolerant microsclerotia.
Use of microsclerotia for insect control
Applying an insecticidally effective amount of the produced microsclerotia to the locus of insects, thereby controlling them.
Application targeting specific fungi and insects
Specifying the fungus as Metarhizium species, particularly Metarhizium anisopliae, and targeting control of soil-dwelling insect pests such as root weevils, soil grubs, rootworms, wireworms, fruit flies, root maggots, termites, and canopy or bark dwelling insects including emerald ash borer, gypsy moth, and pecan weevil.
Application methods
Applying the microsclerotia to soil, greenhouse soilless potting mixes, and onto plant bark and canopy for effective biological control of the insects.
The independent claims cover the method of producing microsclerotia with defined media compositions and their application as biological control agents against a wide variety of insect pests, with specificity as to fungal species, targeted insects, and modes of application, highlighting the production of desiccation tolerant, infective microsclerotia as the core inventive contribution.
Stated Advantages
Microsclerotia are desiccation tolerant and survive low-cost air drying to low moisture levels.
They exhibit excellent shelf-life at both room and refrigerated temperatures.
Microsclerotia can be processed into particle sizes compatible with conventional granular pesticide applicators.
They sporulate profusely upon rehydration, producing large numbers of infective conidia rapidly.
They offer comparable or superior infectivity against insect pests compared to traditional conidia-based granular formulations.
They overcome limitations of previous fungal formulations such as poor shelf-life, high costs, and incompatibility with conventional farm equipment.
Documented Applications
Control of soil-dwelling insect pests including root weevils, soil grubs, rootworms, wireworms, fruit flies, root maggots, subterranean termites, corn rootworms, black vine weevils, citrus root weevils, sugar beet root maggots, cabbage, turnip, onion and seedcorn maggots, carrot rust fly, sweet potato weevils, Japanese beetles, and European chafers.
Control of canopy and bark dwelling insects such as emerald ash borer, gypsy moth, and pecan weevil.
Application to soil in agricultural fields, orchards, greenhouses, gardens, or lawns, as well as onto tree bark, plant canopy, and as seed coatings.
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