ANNUAL REPORT. 1938 99 



caused; seasonal abundance; life history, seasonal history, and habits; 

 and control of the carrot rust fly, which is the most destructive insect 

 pest of carrots. Cultural practices which provide unfavorable conditions 

 for development and reproduction are important factors in controlling 

 this pest. Spraying or dusting carrots for pest control is not generally 

 considered practical or economical in Massachusetts. Diiections are 

 given, however, for the use of materials which have proved successful in 

 controlling the rust fly in case the value of the crop seems to warrant the 

 expense of such treatment. 



353 Leaf-Feeding Insects of Shade Trees. By \V. B. Becker. 83 pp. July 1938. 



The aim of this bulletin is to make available to the people of Massachu- 

 setts information regarding the habits and control of the more important 

 insect pests defoliating the broad-leaved deciduous shade and forest trees. 

 The insects discussed are those most commonly encountered, together 

 with a few which have not yet been reported from Massachusetts but 

 are to be found close to its borders. The description of the insects is 

 accompanied in most cases by photographs of the insect in some of its 

 stages or of the injur\- which it causes. The bulletin is particularly useful 

 to tree wardens and others who are charged with the care and protection 

 of shade trees. 



354 Ascorbic Acid (Vitamin C) in Tomatoes and Tomato Products. By Walter 

 A. Maclinn and Carl R. Fellers. December 1938. 



Tomato ranks among the richest and most widely used of antiscorbutic 

 foods. Sampling methods, reagents, and technique were studied in adapt- 

 ing the chemical methods to the problem of evaluating the tomato as an 

 antiscorbutic. Effect of season, variety, maturity, storage, and other 

 factors influencing the ascorbic acid content of canned and fresh tomato 

 products were studied. Tomato varieties and strains showed a range of 

 74 to 249 international units of \itamin C per ounce. Commercial brands 

 of tomato juice contained 40 to 100 international units per ounce, and a 

 variation from 28 to 85 units per ounce was found within one brand. 



Control Bulletins 



92 Seed Inspection. By F. A. McLaughlin. 80 pp. February 1938. 



93 Eighteenth Annual Report on Eradication of PuUorum Disease in Massa- 

 chusetts. By the Poultr\ Disease Control Laboratory. 11 pp. June 1938. 



94. Inspection of Commercial Feedstuffs. By Philip H. Smith. 68 pp. Octo- 

 ber 1938. 



95 Inspection of Commercial Fertilizers. By H. D. Haskins. 51 pp. Octo- 

 ber 1938. 



96 Seed Inspection. By F. A. xMcLaughlin. 102 pp. November 1938. 



97 Inspection of Agricultural Lime Products. B\- H. D. Haskins. 9 pp. 

 December 1938. 



Meteorological Bulletins 



589-600, inclusive. Monthly reports giN ing daily weather records, together with 

 monthly and annual summaries. B\ C. 1. Gunness. 4 pp. each. 



Reports of Investigations in Journals 



Numbered Contribulions 



276 Samii correlations in plant-tissue composition, decomposition products, and 

 effect upon crop rotation with tobacco. Walter S. Eisenmenger. Jour. 

 Agr. Research 56 (4):309-316. 1938. 



The plants studied for their effect on the tobacco crop were corn, tim- 

 othy, redtop, ragweed, horseweed, and tobacco. The results indicate that 

 plants containing the higher values of lignin, pentosans, high carbon- 

 nitrogen ratios, and a subsequent low tendency to protein decomposition 

 in soil may be suspected of being undesirable for tobacco rotation. 



