Spore Preparations Research Articles

Investigations with New Insecticides for Codling Moth Control

Orchard trials with new insecticides for control of codling moth (Carpocapsa pomonella (L.)) on pears were conducted in two orchards in northern California during 1956. Diazinon alone, a combination of Diazinon and DDT, Thimet, Dipterex and a spore preparation of Bacillus thuringiensis Berliner failed to give satisfactory control. Trithion gave variable results, showing promise in one trial, but providing poor control in another. Hercules AC-528 showed some promise, and ryania, Sevin (N-methyl-l-naphthyl carbamate) and Guthion gave codling moth control comparable to the standard dosage of DDT. During 1957, orchard trials were continued on pears, and Sevin and Guthion gave good codling moth control. Guthion also controlled the European red mite (Panonychus ulmi (Koch)), and both Guthion and Sevin reduced a lepidopterous leaf miner infestation to a low level. Ryania, at a low dosage, plus a spreader-sticker, failed to provide adequate reduction of fruit injury by the cooling moth. In a New town Pippin apple orchard, a heavy codling moth infestation was found following grower application of a full DDT program. Field trials during 1957 in this orchard with DDT strongly indicated a resistance to this compound. In the same orchard, Trithion, ryania, Sevin and ethion provided satisfactory control of a heavy infestation. Trithion and ethion also provided control of European red mite, and Sevin prevented a build-up of the apple aphid Aphis pomi DeG. No serious phytotoxic effects were noted on pears or apples following the use of the experimental insecticides.

THE GERMINATION AND ENZYMIC ACTIVITIES OF BACILLUS SPORES AT LOW TEMPERATURES

SUMMARY: Well washed spore preparations of Bacillus cereus and B. subtilis were suspended in various nutrient broths, soil extracts, autoclaved soil of various moisture contents, and in two inorganic solutions, phosphate buffer, pH 7·2 and Ringer's solution. These were incubated at 8°, 5°, 1° and 0° for periods up to 270 days. Periodic total and spore counts on plates indicated a progressive decrease in each, associated with germination taking place in all conditions except in the two inorganic media. Enzymic tests indicated secretion and activity of nitratase and gelatinase and, with spores of B. pasteurii, urease, as a result of germination. B. subtilis germinated to a greater extent than B. cereus in each of the nutrient media. Germination of both organisms at 5° was also observed in L‐ and D‐alanine: in the latter it was probably the result of racemization to the L‐form.

Enzymes related to carbohydrate metabolism in uredospores of wheat stem rust.

Cell-free extracts of uredospores of wheat stem rust contained enzymes that with the addition of triphosphopyridine nucleotide can oxidize mannose-6-phosphate, glucose-1-phosphate, fructose-6-phosphate, and glucose-6-phosphate, to pentose-5-phosphates, and the latter are converted to sedoheptuIose-7-phosphate and glyceraldehyde-3-phosphate through the transketolase reaction. Diphosphopyridine nucleotide linked α-glycerol phosphate dehydrogenase, triose isomerase, and aldolase activities were also detected. However, transaldolase activity was not found in the spore preparation. These findings support the idea that the glucose-6-phosphate oxidation pathway is actively involved in the carbohydrate metabolism of rust fungi.