26 MASS. EXPERIMENT STATION BULLETIN 449 



growth varying from extremely prostrate to erect. Most of these tomatoes are 

 primitive and were obtained either directly from South America or through the 

 Office of Foreign Plant Introduction, U. S. Department of Agriculture. From 

 duplicated tests in the greenhouse, some promising types immune to the late 

 blight fungus have been found. These represent survivals in the presence of 

 complete devastation of the rest of the planting from the disease. These plants 

 are being grown for seed and further study before undertaking a contemplated 

 breeding program. 



Causes and Control of Decay of Squash in Storage. (E. F. Guba, VValtham.) 

 The objective was to learn the value of fungicidal protectant treatments in the 

 field in relation to squash keeping. A field of squash was maintained and spraj'ed 

 during the summer months. In addition, the squash were immersed in fungicides 

 after harvest and checked periodically for infection during the winter storage 

 season. Careful records of yields and disease were maintained. 



Black Rot, caused by the fungus Mycosphaerella citrullina (C.O.Sm.) Gross, 

 was unusually destructive on Butternut and Hubbard squash. Unusually warm 

 weather up to December was an important factor contributing to the losses in 

 storage. In the field the disease was best controlled with Fermate which yielded 

 3.2 percent infected squash; Parzate, 2.8 percent; and Zerlate, 1.7 percent. Un- 

 sprayed plots averaged 31 percent infected squash. 



The successful control of Black Rot of Butternut squash in storage requires 

 protectant spraying with fungicides in the field. Dipping the squash at harvest 

 in Parzate, Phygon, or Zerlate suspensions controlled Black Rot well only when 

 the squash had been sprayed in the field. When the stem end was removed, 

 stem end infection was as prevalent as ^ide infection. When the stems were re- 

 tained, there was less disease at the stem end than on the sides. Painting the 

 stem end with Phygon or Zerlate greatly reduced stem end infection, especially 

 among squash from plots sprayed with fungicides in the field. The results 

 show the possibilities of reducing Black Rot in storage by protectant field 

 spraying and disinfestation of the squash with fungicides prior to storage. 



Resistance to Fursarium dianthi Prill et Del,, the Cause of a Serious Carna- 

 tion Wilt Disease. (E. F. Guba, Waltham.) Considerable hybridizing has been 

 done, and seedlings have been grown from successful crosses. Some 75 promising 

 seedlings have been propagated from cuttings during the winter of 1947-48. 

 These have been placed with two growers, recommended by the New England 

 Carnation Growers Association, for further judging, and any that are acceptable 

 will be subjected to tests to determine their reaction to disease, and notably to 

 Fusarium Branch Rot. 



Investigations of Fungicides which Promise Value in Apple Disease Control. 



(E. F. Guba, Waltham.) The objective implied by the original title of this 

 project, i.e. "Interrelation of Wettable Sulfur, Lead Arsenate and Lime in Apple 

 Spraying", has been attained. Project now is designed to acquaint growers 

 with the advantages and limitations of new materials as protectants and eradi- 

 cants for scab. 



Lime or clay appeared to depreciate the fungicidal value of Puratized Agri- 

 cultural Spray. Fermate or high grade wettable sulfur added to Puratized Agri- 

 cultural Spray can be beneficial. Both Phygon and Flotation Sulfur Paste gave 

 excellent scab control. Phygon causes a serious chlorosis of the foliage which 

 appears to be corrected satisfactorily by the addition of twice as much Epsom 

 salt. Epsom salt added to the spray produced darker green foliage. 



