Donald J. Daigle

Progress in the Production, Formulation, and Application of Mycoherbicides

Chemical herbicides have been the mainstay for weed control practices in the United States since the end of World War II and are responsible for much of the unparalleled increased crop productivity that has occurred during this period (38). The high costs involved in developing and registering chemical herbicides and recent trends in environmental awareness have prompted researchers to investigate alternative systems of weed control. Ideally, such a system would control target weeds at or near the same levels as that achieved with chemical herbicides, while at the same time not posing a threat to either the environment or nontarget organisms.

Solid-state fermentation plus extrusion to make biopesticide granules

Five fungal biocontrol agents useful in agriculture were grown on rice flour in plastic bags. The flour, infested with Colletotrichum truncatum, an Alternaria sp., Paecilomyces fumosoroseus, or atoxigenic Aspergillus flavus and A. parasiticus, was mixed with wheat flour, kaolin, and water and extruded into granules. The inoculum survived extrusion and fluid bed drying at 50°C 3–92 times better than inoculum produced in liquid fermentation. Depending on the agent, the high level of flour infestation permitted a 1:9 to 1:1600 dilution to yield the 1×106 cfu/g in the final product which is usually needed for biocontrol efficacy.

Chemistry of Hydroxymethyl Phosphorus Compounds Part II. Phosphonium Salts

The chemistry of the hydroxymethyl phosphonium salts and their derivatives is reviewed, with major emphasis on reactions in which the quaternary structure of the phosphonium salts is preserved.

Formulating a Weed-Suppressive Bacterium in “Pesta”1

“Pesta” is a granular, extruded product made from a cereal grain flour and any biological control agent. A strain of Pseudomonas fluorescens, BRG100, which is a pathogen of green foxtail, has been formulated into a Pesta product. P. fluorescens BRG100 survived processing best in oat flour, and the addition of 20% (wt/wt) maltose extended the shelf life of the product to more than 32 wk. Field studies of 8-wk duration showed that a Pesta product containing BRG100 suppressed green foxtail emergence by as much as 90%. An optimally formulated and processed Pesta product has potential for the biocontrol of green foxtail. Nomenclature: Pseudomonas fluorescens; green foxtail, Setaria viridis (L.) Beauv. #3 SETVI; oats, Avena sativa L. # AVESA. Additional index words: Biological control, encapsulation, lactose, maltose. Abbreviations: cfu, colony-forming units; DRB, deleterious rhizobacteria.

Production of Conidia of Alternaria cassiae with Alginate Pellets

Abstract Formulations of alginate-encapsulated mycelia are used to generate spores for mycoherbicidal application to weed-infested fields and for bulk production of spore-based products. Spore yield of such formulations is a primary determinant of product efficacy. A number of parameters of the alginate process were studied to develop an optimal alginate formulation for field application of Alternaria cassiae , a mycoherbicide for sicklepod ( Cassia obtusifolia ). The composition of the fermentation medium and of the filler used in formulation and the fermentation time were important variables. The addition of nutrients to the mycelial homogenate after fermentation increased sporulation but the amount and ratio of nutrients in the fermentation medium had a greater influence on spore yield from pellets. Optimal sporulation resulted from mycelia produced during a 60- to 70-h fermentation in 2.4% dehydrated potato dextrose broth and 14% V-8 vegetable juice and entrapped in pellets containing corn cob grits as the filler.

Chemistry of Hydroxymethyl Phosphorus Compounds: Part III. Phosphines, Phosphine Oxides, and Phosphonium Hydroxides

The chemistry of the hydroxymethyl phosphines, phosphine oxides, and phos phonium hydroxides is reviewed in relation to flame retardant finishing of cotton.2

Chemistry of Hydroxymethyl Phosphorus Compounds Part IV. Ammonia, Amines, and THPOH: A Chemical Approach to Flame Retardancy

The reactions of base-neutralized tetrakis(hydroxymethyl)phosphonium salts with amines and ammonia are reviewed. The mechanisms of these reactions are examined with reference to the application technology of the THPOH—NH3 process. Previ ously unpublished material and theories are included to present the current status of this area of research.

Alginate Encapsulation of the White Rot Fungus Phanerochaete chrysosporium

Abstract. In the laboratory, the white rot fungus Phanerochaete chrysosporium degrades numerous organic pollutants. Lack of a slow-release delivery system to toxic waste sites, for this and other fungi, however, constitutes an important barrier to practical implementation. In this study, the use of calcium alginate as an encapsulant for mycelia was investigated; samples were in the form of pellets 1–3 mm in diameter. When refrigerated, alginate-embedded mycelia of P. chrysosporium were viable for one year, both with and without nutrient supplementation. At room temperature, in the absence of nutrient supplementation, viability decreased sharply within 2 months. Addition of sawdust or corncob grits extended the viability of alginate-embedded mycelia; nevertheless, after 9 months only about 20% of the pellets stored at room temperature yielded fungal growth. Spores of P. chrysosporium, embedded in alginate pellets together with corncob grits, gave 75% viability after 9 months of storage at room temperature. Alginate-embedded mycelia were used in Petri plate toxicity tests with 2,4,6-trinitrotoluene (TNT) and gave more rapid and reproducible results than tests performed with mycelial plugs. These experiments demonstrated the feasibility of encapsulating P. chrysosporium in calcium alginate pellets, thus providing a potential method of delivering white rot fungi to toxic waste sites, as well as for developing a system of standardized toxicity testing in plate assays.

Chemistry of Hydroxymethyl Phosphorus Compounds Part I: Introduction

The current status of applied technology for production of flame retardant cotton fabrics is reviewed, with emphasis on some of the technical problems that remain to be solved. Our thesis is that progress can best be made through a better under standing of the chemistry of the hydroxymethyl phosphorus compounds and their derivatives. The similarity of mechanisms of the reactions of hydroxymethyl phos phorus compounds to those of some of the well studied classical organophosphorus reactions (e.g., the Wittig reaction) are noted and discussed. The chemistry of both the ammonia cure and heat cure processes are examined, with emphasis on reaction mechanisms for N-methylol reactants and the competitive nature of the reactants, including cellulose, in the system. An outline of the series of papers is provided.

Preparation of fibrous cellulose formate by the action of thionyl chloride in N,N-dimethylformamide

Abstract Cotton cellulose yarn, either in the untreated state, or altered by swelling pretreatments involving mercerization or solvent-exchange, or both, reacts readily with solutions of thionyl chloride in N , N -dimethylformamide at room temperature. Subsequent hydrolysis produces cellulose formate as the major product; this derivative is presumably formed via reaction of the cellulose with the iminium salt, and a chlorodeoxycellulose. The reaction variables studied were the effect of ( a ) preswelling the cellulose in N , N -dimethylformamide, ( b ) the reaction time, ( c ) the concentration of thionyl chloride, and ( d ) the moisture content of the cotton prior to preswelling and reaction. The effect of various pretreatments on the type and rate of reaction which the cotton undergoes was also determined. The stability of the formyl group and of the sulfurous acid monoester group to hot water and to dilute ammonium hydroxide, as well as the tensile properties of yarns treated with thionyl chloride and N , N -dimethylformamide, were investigated.