ANNUAL REPORT, 1944-45 21 



Tomato seedlings emerged and grew more slowly if seeds treated with Arasan 

 were planted in untreated soil than if untreated seeds were planted in soil which, 

 immediately after seeding, received an application of formaldehyde, one tea- 

 spoonful per gallon of water. And, in untreated soil, tomato seedlings made mor^ 

 growth in their first three weeks if seeds had been treated with red cuprous oxide 

 than if they had been treated with Arasan. 



In soil heavily infested with damping-off fungi, principally species of Pythium, 

 and having a relatively low moisture content at the time of seeding, there was 

 usually less damping-off, and final stands of cabbage, tomato, pepper, lettuce, 

 beet, and onion were usually much better if soil was not watered until 4 to 6 

 days after seeding, than if the soil was first watered immediately after seeding, 

 as it commonly is. Similar postponement of the first watering after seeding also 

 resulted in improved stands of Aubrietia, China aster, and zinnia. 



Work done on the control of smut and pink root-rot of onion was with the 

 cooperation of Thomas Sproston, Jr. A paper entitled, "Control of onion smut 

 by fungicides applied to the soil" was presented at the Annual Meeting of the 

 New England Division of the American Phytopathological Society. An abstract 

 of this paper has been accepted for publication by Phytopathology. Onion smut, 

 caused by Urocystis cepulae C. C. Frost, was well controlled by 58 pounds Fer- 

 mate mixed with 1500 pounds of a 5-8-7 fertilizer per acre, applied immediately 

 before seeding. Fertilizer used alone lessened the severity of smut but of course 

 not enough. The percentage of seedlings which, in a typical instance, became 

 infected with smut was 88 percent in a soil without treatment, 56 percent in 

 this soil with fertilizer, and 1 percent in this soil with fertilizer to which Fermate 

 had been added. Fermate so used was not injurious to growth of plants. There 

 were comparable results when Arasan was similarly used. Smut was well con- 

 trolled by Puratized N5-X and also by the nitrites of sodium and calcium, but 

 Fermate used as above described gave better results. Urea and calcium cyana- 

 mide gave fair control but, as used, they caused some injury to onion seedlings. 



Soil in which onions had grown poorly and in which they were known to have 

 had pink root-rot, was variously treated before planting onion sets or sowing 

 onion seeds in it. Numbers of onion seedlings which lived, as compared with 

 numbers in untreated soil, were increased 80 percent by sodium nitrite, almost 

 as much by Fermate. Fermate was ineffective, however, in preventing pink 

 root-rot. But with pink root-rot severe on onions from sets in untreated soil 

 (a species of Fusarium was isolated from diseased roots), the disease was at least 

 partly controlled and early growth was markedly improved by copper sulfate 

 200 pounds or sodium nitrite 400 pounds per acre. 



Tomato Leaf Mold Caused by the Fungus Cladosporium fulvutn Cke. (E. F. 



Cuba, Waltham.) Previous reports by the writer describe the discovery of 

 resistance to all local strains of Cladosporium among certain primitive tomatoes 

 received from the Division of Plant Exploration and Introduction, U. S. De- 

 partment of Agriculture, and his progress in crossing these types with the Bay 

 State variety. The Bay State tomato (Mass. Agr. Expt. Sta. Bui. 393) is now 

 very susceptible to a variant strain of leaf mold. 



The best approach to desirable types of greenhouse forcing tomatoes appeared 

 among the progeny of successive generations of crosses of Bay State with a prim- 

 itive type No. 129882 from Peru and No. 112215 from Ecuador. 



A further series of crosses was made of selected lines of the above hybrids 

 with Vetomold-121, Bay State, Waltham Forcing, and Marglobe. The crosses 

 with No. 112215 are giving the best performance. The F3 generation will be 

 grown in several commercial greenhouses for trial in the fall growing season 



