An isolate of Trichoderma harzianum capable of lysing mycelia of The wheat bran preparation of T. harzianum increased growth of bean Sclerotium rolfsii and Rhizoctonia solani was isolated from a soil naturally plants in a noninfested soil and it controlled S. rolfsii more efficiently than a infested with those pathogens. In culture, T. harzianum grew better than S. conidial suspension of the same antagonist. An uninoculated wheat bran rolfsii and invaded its mycelium under growth conditions adverse to the preparation increased disease incidence. In naturally infested soils, wheat pathogen; eg, high pentachloronitrobenzene concentrations, high pH bran preparations of T harzianum inoculum significantly decreased levels, or low temperatures. Under greenhouse conditions, incorporation of diseases caused by S. rolfsii or R. solani in three field experiments with the wheat-bran inoculum preparation of T harzianum in pathogen-infested beans, cotton, or tomatoes, and they significantly increased the yield of soil significantly reduced bean diseases caused by S. rolfsii, R. solani, or beans. both, but its biocontrol capacity was inversely correlated with temperature.

A steady decrease of extractable [14C] parathion residues in soils over a 1-month incubation period was accompanied by an increase of unextractable, bound 14C-labeled residues, resulting finally in total recoveries of extracted plus bound residues of 80 to 87 percent of the applied radiocarbon. Soils containing bound residues were nontoxic to fruit flies. Binding of 14C-labeled residues was related to the activity of soil microorganisms; soil sterilization resulted in a reduction of binding by 58 to 84 percent. Under flooded (anaerobic) conditions, the binding of compounds labeled with 14C doubled, and parathion was reduced to aminoparathion. Reinoculation of sterilized flooded soil fully reinstated the binding capacity. [14C] Aminoparathion was preferentially bound to soil, since its binding within 2 hours was 30 times greater than that of [14C] parathion. Because of the existence of formerly "unseen," unextractable residues, the concept of "persistent" and "nonpersistent" pesticide residues might have to be reconsidered.

No abstract

Text Book of Practical Organic Chemistry", 1st ed, Longman's Green and Co., London, 1948.

Accelerated degradation of vernolate, EPTC and butylate but not of cycloate was detected in soils from three locations in Israel which were treated annually with vernolate. Repeated application of EPTC to soils with and without a history of vernolate application, under laboratory conditions, resulted in a progressive increase in its rate of dissipation with each application. Accelerated degradation of EPTC was also rapidly induced by mixing small amounts (5%) of soil with a history of vernolate treatment with soil that had never received vernolate. Liberation of 14CO2 from [14C]EPTC was more rapid in vernolate‐treated soils than in untreated soils, indicating a development of microbial populations in soil capable of rapidly degrading the EPTC. Degradation of [14C]EPTC was faster in soil previously cropped with maize than in non‐cropped soil, but slower in soils cropped with cotton or peanuts.

No abstract

The effect of oat straw, green bean plants, and cellulose on the infection index and saprophytic activity of Rhizoctonia, and the effect of chitin, N-supplemented oat straw, and green cotton plants on the infection index, saprophytic activity, and soil microflora was tested. A modified method for counting Rhizoctonia-antagonistic bacteria, actinomycetes, and fungi was developed. A relationship between efficiency of the amendments in decreasing infection index and in suppressing the saprophytic activity of Rhizoctonia was observed at the end of the experimental period. Decrease in infection index and saprophytic activity was accompanied by increase in counts of general and antagonistic soil microorganisms. This increase was especially pronounced in chitin-amended soil. The possible mechanism of the biological control of Rhizoctonia by chitin is discussed.

The septal pore apparatus of Rhizoctonia solani was studied in hyphae of different ages by scanning electron microscopy. The formation of the septal pore apparatus begins with an annular swelling followed by the development of a dome-shaped perforated pore cap, which usually has three apertures. In older hyphae, the septal pore apparatus is absent, and the septal pore may be plugged. In some cases, four apertures are observed in the pore cap.