Drug – bio-affecting and body treating compositions – Whole live micro-organism – cell – or virus containing
Reexamination Certificate
1996-08-08
2002-09-24
Low, Christopher S. F. (Department: 1653)
Drug, bio-affecting and body treating compositions
Whole live micro-organism, cell, or virus containing
C424S093300, C424S093460, C424S093400, C424S404000, C424S405000, C424S407000, C514S04400A, C435S235100, C435S238000, C435S252500, C435S254100, C435S254200, C435S255100, C435S258100, C435S243000
Reexamination Certificate
active
06455036
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
With the increase in emphasis within the agricultural community on using biocontrol agents as substitutes for chemicals in the control of weeds, insects, and other pests, considerable research has been directed to compositions and mechanisms for delivering the agents in a way which will preserve their effectiveness in the field. This invention relates to a novel granular formulation of biocontrol agents.
2. Description of the Prior Art
Dunkle et al. [
Environ. Entomol
. 17:20-126 (1988)] and U.S. Pat. No. 4,859,377 show a granular formulation of
Bacillus thuringiensis
(
B.t.
) encapsulated within a starch matrix. The advantage of this product over prior formulations was that it allowed incorporation of various additives such as sunlight protectors and palatable feeding stimulants, thereby reducing the amount of active ingredient necessary for control. Trimnell et al. [
J. Controlled Release
7: 263-268 (1988)] reported a sprayable herbicide formulation utilizing pregelatinized corn starch and flour. These sprays were designed to coat plant leaves with a thin film of material which would autoencapsulate (encapsulate the active agent in situ) upon drying and thereby allow sustained release of active ingredient. However, within 2-3 days after application, these films were found to peel away from the plant leaves. In general, sprayable formulations of
B.t
. lose activity within 2-4 days following application to plant foliage in the field [Morris,
Can. Ent
. 115: 1215-1227 (1983); Beegle et al.,
Environ. Entomol
. 10: 400-401 (1981); Leong et al.,
Environ. Entomol
. 9: 593-599 (1980)].
Shasha et al. [U.S. Pat. No. 5,061,697 and
J. Econ. Entomol
. 83(5): 1813-1817 (1990)], teach sprayable, starch-based formulations for autoencapsulating biological control agents, such as pathogenic bacteria and viruses. These compositions incorporate a sugary material to promote adherence of the encapsulated agent to treated foliage.
Walker et al., U.S. Pat. Nos. 4,718,935 and 4,767,441, teach pelletization of infective propagules of fungal plant pathogens using aqueous solutions of sodium alginate and calcium chloride. This system relies upon the ability of the fungus to grow through the gelled alginate matrix to the pellet surface, where spores of the fungus are produced and released to the target plant.
Quimby et al. (U.S. Pat. No. 5,358,863) teach forming granules by encapsulating bacteria, fungi or nematodes useful for controlling agricultural pests in alginate, starch or wheat gluten, and then coating the granules with an invert oil that forms a water-in-oil emulsion and an absorbent for the oil to make the coated granules free-flowing. See also Amsellem et al. [
Phytopathology
, 80(10):925-929 (1990)]. The oil slows the drying of the organisms to maintain their vitality. The resulting products are applied by spraying through large-orifice nozzles.
McCabe et al. (U.S. Pat. No. 4,530,834) teach the preparation of entomopathogenic fungal insect control agents by culturing mycelia in a suitable medium, harvesting the growing mycelia, treating the mycelia with a protective agent such as maltose or glucose, and drying the product.
Mungier et al. [Appl. and
Environ. Micro.
, 50(1): 108-114 (1985)] presents a study on the survival of bacteria and fungi in relation to water activity and the solvent properties of water in biopolymer gels. This reference shows that cells survive at a water activity (a
w
0.069 and below and die at an a
w
above that.
Caesar et al. [Appl. and
Environ. Micro.
, 57(1): 168-172 (1991)] demonstrated that strains of Pseudomonas and members of the family Enterobacteriaceae could be conditioned for improved shelf life in simple dry formulations by aging, exposure to osmotica, or growth on media amended with sucrose or betaine. Similarly, Leslie et al. [
Appl. and Environ. Micro.
, 61(10): 3592-3597 (1995)] teach that when
E. coli
and
B.t
. were dried in the presence of trehalose or sucrose, their survival rate was greatly enhanced over organisms dried without the sugars. The increased survivability is attributed to lowering of the transition temperature (T
m
) of the dry membranes by replacement of the water between the membrane lipid headgroups with the disaccharide.
Connick et al. [U.S. Pat. No. 5,074,902 and
Biological Control
1: 281-287 (1991)] teach encapsulation of fungal propagules in a wheat gluten matrix, resulting in a pasta-like product referred to as “Pesta”. Pesta is prepared from a dough of wheat flour, kaolin filler, fungus and water. The dough is rolled into a thin sheet, air-dried, and cut with a pasta maker or ground into granules. Upon application of the product to the soil, the fungi grow and sporulate on the granules. The Pesta technology has also been shown by Connick et al. [
Journal of Nematology
25(2):198-203 (1993)] to be useful for the encapsulation of nematodes (
Steinernema carpocapsae
). In
Biocontrol Science and Technology
6:277-284 (1996), Connick et al. show that, at relatively high a
w
, sucrose helps maintain Colletotrichum sp. conidia viability in Pesta granules during storage.
SUMMARY OF THE INVENTION
We have now unexpectedly discovered a simple and inexpensive procedure for preparing a stabilized, granular, biocontrol agent which can optionally be formulated as a rehydratable sprayable composition. The invention is applicable to a wide variety of living, pathogenic biocontrol agents useful in the management of all types of agricultural pests.
In accordance with this discovery, it is an object of the invention to provide a facile, universal, and industrially acceptable procedure for granular formulation of sensitive biocontrol agents.
It is also an object of the invention to formulate biocontrol agents without loss of viability and with a high degree of stability under storage and field conditions.
Another object of the invention is to prepare biocontrol products that are clean, easy to handle, and have relatively low crop phytotoxicity.
A further object of the invention is to package biocontrol agents into formulations that can be applied with conventional agricultural sprayers.
Other objects and advantages of this invention will become readily apparent from the ensuing description.
DETAILED DESCRIPTION OF THE INVENTION
The primary components of the formulations of the invention include (1) a biocontrol agent, (2) a water absorbent material, (3) a membrane stabilization agent, and (4) a granulating agent. Oil is an optional primary component. The Biocontrol Agent
The biocontrol agents contemplated for use herein include without limitation all bacteria, fungi, yeasts, viruses, microsporidians, protozoa, nematodes and other such organisms that are pathogenic toward target pests. Of course, any component of the organism or stage of its life cycle which is infective to the host upon contact or ingestion is considered to be within the scope of the invention. For instance, in the case of
B.t
., the vegetative cells, spores, and proteinaceous crystals are all effective in directly or indirectly killing host insects susceptible to
B.t
. It is also known that naturally occurring and synthetic vectors such as plasmids, phages, and various DNA/RNA constructs have potential for functionally modifying higher organisms, and therefore are also included herein as being within the scope of the term “biocontrol agent.” Examples of other agronomically important pest pathogens besides
B.t
., without limitation thereto include: other entomopathogenic bacteria such as
B. sphaericus
, and
B. popillae
; plant pathogenic bacteria, such as Pseudomonas spp. and Agrobacterium; plant pathogenic fungi, such as Sclerotinia, Rhizoctonia, Fusarium, Alternaria, Colletotrichum, and Sclerotium; entomopathogenic fungi, such as Pandora, Beauveria and Conidiobolus and the yeasts; entomopathogenic viruses, such as
Autographa californica
nuclear polyhedrosis virus, and Heliothis spp. virus; microsporidian
Birdsall Jennifer L.
Boyette Clyde D.
Caesar Anthony J.
Connick, Jr. William J.
Grey William E.
Fado John D.
Low Christopher S. F.
Ribando Curtis P.
Silverstein M. Howard
The United States of America as represented by the Secretary of
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