26 MASS. EXPERIMENT STATION BULLETIN 388 



yellowish infection flecks and ultimately necrosis. On the lower surface of the 

 spots, under moist conditions, the fungus sporulates rather freely, although it 

 is much less virulent on Bay State than the original prevalent form of the fungus. 

 Both L. pirn pin ellifolium and L. hirsutum show a high immunity reaction to the 

 original physiologic. form of Cladosporium. L. peruvianum (L.) Mill, is immune 

 to both physiologic forms but peruvianum will not hybridize with esculentiim. 



Causes and Control of Decay of Squash in Storage. (E. F. Guba and C. J. 

 Gilgut, Waltham.) Gourds instead of squash were treated with various disin- 

 fectants and chemical coatings after harvest to determine to what extent these 

 treatments influence keeping. The organisms causing decay of squash similarly 

 attack gourds and the results from such treatments are generally applicable. 



The merit of spraying gourds with Bordeaux mixture 4-4-50 and 1 pound 

 calcium arsenate during the growing season was investigated, although it is 

 recognized that the spraying of squash is difficult. The results indicate that 

 fungicidal field treatments result in less decay after harvest and that the progress 

 of decay is further inhibited by coatings of shellac. The value of disinfection 

 between harvest and storage is not clearly shown. A dry ventilated storage 

 following protection in the field with Bordeaux mixture and calcium arsenate 

 was definitely advantageous in the control of decay. 



It is apparent, particularly as the result of this season's work with gourds, 

 that considerable infection responsible for decay in storage may take place in 

 the field, without being evident at harvest. 



Gardenia Stem Canker. (C. J. Gilgut, Waltham.) It was determined from 

 a histological study of gardenia cankers that the hyphae of the infecting fungus, 

 Phomopsis gardeniae Hans. & Scott, are confined to the discolored bark and wood 

 of the cankered section of the stem. Cuttings taken from diseased plants and 

 from healthy plants did not become infected when propagated side by side in 

 clean sand, nor did plants from these cuttings become cankered when grown in 

 greenhouse benches. 



Disease Resistance and Heredity of Carnations. (E. F. Guba cooperating 

 with H. E. White, Waltham.) Approximately 75 varieties of carnations have 

 been studied for their reaction to fungus wilt diseases. Also, growers have in- 

 dicated the performance of a long list of varieties in relation to these diseases 

 under their respective growing conditions. In a compilation of these reports 

 and tests, it is apparent that certain carnation varieties have rather consistently 

 maintained healthy growth. The wilt diseases under consideration in this study 

 are caused by Alternaria diantJii (blight), Rhizoctonia solani (stem rot), Fusarium 

 dianthi (branch rot) and F. avenaceum and F. culmorum (stem and root rot), 

 ,and are not equally prevalent. Frequently, only one of these diseases may be 

 troublesome year after year in the same establishment. Twenty-six varieties 

 showing the greatest promise as sources of disease resistance under natural con- 

 ditions have been selected for further study. The reactions of these varieties 

 to each wilt disease in so far as available will be more carefully scrutinized under 

 more favorable conditions for disease and artificial methods of inoculation before 

 hybridization studies are undertaken. The results of this program should deter- 

 mine the nature, justification, and direction of further efifort in the development 

 of desirable disease-resistant types of carnations. 



Miscellaneous Tests and Experiments. (E. F. Guba and C. J. Gilgut, Waltham.) 



L Apple Scab Control. Ground and chemically prepared sulfurs of a max- 

 imum particle size of 50 and 3 microns respectively were compared on an equiva- 

 lent sulfur basis, and in combination with lead arsenate, and lead arsenate and 



