A storage disorder of sweet cherries referred the disorder than storage at a temperature to as surface pitting is described and illus-several deglees higher. Neither mineral foliar trated. Differeni handling, packaging and stor-sprays nor controlled atmosphere storage age treatments influenced the amount of the were effective in preventing surface pitting, disorder, but did not prevent it.

Under carefully controlled laboratory conditions, a highly virulent strain of Erwinia amylovora coinhabited susceptible host tissues with a yellow saprophytic bacterium, which was invariably isolated from fire blight infected trees, with or without producing symptoms of the disease depending on the status of a number of environmental factors, both climatic and physiological. In particular, variation of temperature and sucrose concentration determined, independently, the equilibrium of a readily reversible alternation of predominance of the two bacteria. It is suggested that E. amylovora may sometimes exist as an avirulent resident on the surface or within healthy host plants when environmental conditions favor growth of the yellow saprophyte rather than the pathogen. Such conditions, which are more likely to be obtained in midsummer and the fall, include temperature fall or rise below or above the optimum for E. amylovora, decreased humidity or diminution of sap flow, and increased sugar content in the host tissues.

Sol~tble carbohydrate of stems of wheat grown in the Lethbridge area followed a similar trcnd in solicl-and hollow-stemmed varieties. At thc time of heading, most soluble carbohydrate was present as fructose, glucose, and sucrose. After heading, the quantities of reclucjng sugars declined, while oligosaccharide and fructosan built up. Oligosacchar~de forn~ed the dorninarlt carbohydrate stored in stems prior to ripening of the grain. In general, the contents of solul~le carbohydrate in stems of Golden Ball were a t a higher level than those of Rescue or Thatcher. Iiescue and Golden Ball, two solid-stemmed varieties resistant t o the wheat stem sawfly, sho\\red no consistent deficiency of soluble carbohydrate in steins a t any growth period.'Manuscript received October 2, 1961. Contribution from the

The gaseous exchange accompanying decomposition of dithiocarbamate fungicides was measured in the Warburg manometer. Sodium diethyl dithiocarbamate decomposed under slightly acid conditions, producing carbon disulphide and a salt of diethylamine. The insoluble zinc and iron salts of dimethyl dithiocarbamic acid also decomposed in a similar fashion, but no carbon disulphide was given off from the more stable copper salt of this compound. The rate of decomposition of these metallic salts fell in the following decreasing order:[Formula: see text]Disodium ethylene bis-dithiocarbamate (nabam) decomposed under slightly acid conditions to produce approximately equal volumes of hydrogen sulphide and carbon disulphide, and presumably left a residue of ethylene thiourea. In distilled water, on the other hand, nabam underwent a slow basic hydrolysis and oxidation, with absorption of approximately two volumes of oxygen, and evolution of one volume of carbon disulphide. Apparently the sulphur fraction which is evolved as hydrogen sulphide from nabam under acid conditions is, under basic conditions, oxidized in solution by atmospheric oxygen to sulphate.

Pbzyfophthora c(~ctorz~tn grew we11 in ammoniuna-salt rnedia b~at saot in nitrate. Co~avcrsely, P. mqttsper?na grew well in nitrate brat not in a~~lllna~ai~~na-salt media. P. parasiticu and %. crythrsseptica grew well in both, but better in that containing nitrate. ABI species grew better in the presence of organic nitrogen.Evidence is presented that iron, zinc, copper, arad manganese are essential trace rnetals and that zinc is req~nired in greater conce~atrations than iron. The optimum requirement for g1rlcose or SLICHOSC was found to be approximately 47;, and the residual hucrose was converted i~a t r~ reducing sugars by all species except P. coctorum. Approximately 507; of the residual sugar remained unchanged inr the cultalres of ahis species. The growth rate and sugar coiasumptian increrased as the thiamine level was increased from 0.2 to 0.8 rangm. per liter, but the coefficierit of sugar utilization remained constant. On the ather hand, !he percentage of nitrogen in the mycelium decreased nlarkedly as the t h i a m~~t e content of the ~nedium was increased. I t is co~~cliided that with media containing 1% alaani~ae an accurate bio-assay sf thiamine can be made over a concentration range of 0.2 to 0.4 Ingm. per liter.