ASYMMETRIC A-FASCICULATA 531 



favorable growth range of the former was pH 2.9 to 6.5, for the latter 3.0 

 to 6.0. The bicarbonate-ion (pH 8.4 in solution) was regarded as toxic 

 to these fungi and its fruit-protective action was attributed to the thin 

 film of the salt which remained after the fruit was dipped. Tompkins (1930) 

 studied the effect of acetaldehyde upon the growth of different citrus 

 pathogens, including P. iialicum and P. digitatum. Germination of conidia 

 was inhibited or dela3'ed at concentrations of 2 to 5 in 10,033, whereas 

 much higher concentrations were necessarj' to kill. Lowering the tem- 

 perature markedly reduced its effectiveness. Melkon (1938) found iodide, 

 bromide, and chloride of lithium to be decreasingly toxic to P. iialicum. 

 Klotz (1934, 1936) studied the effectiveness of nitrogen trichloride and 

 other gases in controlling deca}^ in oranges, reporting concentrations of 

 NCI3 as low as 4-6 mg. /cu. ft. to be lethal to conidia of P. iialicum^ P. digi- 

 tatum, and other fungi after 30 minutes exposure. Chlorine was more in- 

 jurious to the fruit and afforded less protection. NHMeCl could be sub- 

 stituted for NCI3 but was more costh'. Ozone showed onl}^ limited toxicity 

 to the Penicillia and gave no protective action to the fruit. Sulphur dioxide 

 could be used effectiveh^ for sterilization of boxes and equipment. Robson 

 (1935) confirmed Ivlotz's observations regarding the effectiveness of NClj 

 as a gaseous fungicide. 



Gioelli (1932) observed some degree of "antagonism" between Penicil- 

 lium italicum and P. digitatum- when both occurred upon the same fruit, 

 the latter commonly surrounding but not invading areas infected by the 

 former species. Controlled laborator}^ experiments were subsequently 

 made using whole fruit, orange and lemon rind, and s^mthetic media. 

 Thermostable toxins capable of ultra-filtration were isolated from both 

 molds. 



Little biochemical work with Penicillium italicum has been reported. 

 Oxford and Raistrick (1932) reported the isolation of ergosteryl palmitate 

 from P. italicum and strains of P. brevi-compactum Dierckx (see p. 417). 

 Birkinshaw, Charles, and Raistrick (1931) isolated from different strains 

 of P. italicum a substance giving an emerald-green color with FeCU and a 

 purple color with bleaching powder solution. The authors regarded these 

 color reactions as of diagnostic value since they were not observed in other 

 species investigated. 



Karrer (1921) studied the influence of H-ion concentration upon amylase 

 production by Penicillium italicum. 



Penicillium urticae Series 



Outstanding Characters 



Colonies growling rather restrictedly, with margins abrupt, comparatively 

 deep from 1.0 to 2.0 mm. or more, with surface distinctly granular and 



