ANNUAL REPORT, 1944-45 51 



which is particularly resistant to the effects of the oil. Some of the carrot leaves 

 developed a lighter color after spraying, but this disappeared in about a week 

 with no other noticeable effect on the plants. There was no indication of a toxic 

 residue in the soil when these oils were applied at the rate of 80 to 120 gallons 

 per acre, which effected good weed control. The oil costs $.15 to $.20 per gallon, 

 depending on the locality, so that on the average the material to spray an acre 

 costs about $20.00. At the present wage scales it costs approximately $40.00 to 

 hand weed an acre of carrots. 



It is desirable to apply the oil as a flat, fan^shaped spray since this gives much 

 more uniform distribution than a cone spray. The Skinner greenhouse irrigation 

 nozzle ST50 was found to be well adapted to delivering the desired type spray. 

 The oil seemed to give best results when applied at about 100 pounds pressure. 

 Higher pressures developed a drifting mist type of spray that was objectionable. 



It is suggested that this method of weed control be tried on a small scale at 

 first much the same as with other new developments. 



Other details of this method have been published in Massachusetts State 

 College Extension Special Circular 120, and a report also appears in the Pro- 

 ceedings of the American Society for Horticultural Science, Vol. 45. 



The Carotene Content of Carrots. (W. H. Lachman.) Ten varieties and strains 

 of carrots were grown during 1944 and were analyzed for carotene during suc- 

 cessive stages of maturity as well as after storage in a warm room for three weeks 

 and in cold storage at 32°F. for five months. From the results of the analyses it 

 was rather apparent that the carotene content of carrots increased as the root 

 matured. Carotene appeared to be directly correlated with a deep orange colora- 

 tion in both the core and cortex of the carrot. Expressed as thousands of 

 Vitamin A Rat Units per pound, the carotene content of the mature carrots ranged 

 from 51.5 to 98.0; from 76.0 to 156.0 after 3 weeks at room temperature; and from 

 56.5 to 100.0 after 5 months at 32°F. It is noteworthy that the carotene in the 

 carrots was relatively indestructible under various storage conditions, even show- 

 ing an apparent increase which was no doubt due to moisture loss through respira- 

 tion and evaporation. 



Two bunches of California-grown Long Imperator carrots, purchased on the 

 open market early in April, 1945, were found to have a carotene content of 62.0 

 thousand Vitamin A Rat Units per pound. These were bunch carrots and rather 

 small. A similar sample, purchased in early May, 1944, analyzed 98.0 thousand 

 units. These carrots were a little larger, which probably accounts for the greater 

 carotene content. 



Vegetable Breeding. (W. H. Lachman.) A large number of sweet corn inbreds 

 has been produced by inbreeding open-pollinated varieties. One of the most 

 promising of these, Massachusetts No. S, is being increased for production by a 

 large seed grower in Idaho. Massachusetts 8 is an excellent inbred line. It has 

 many of the characteristics of Purdue 39 but is about a week earlier, has a larger 

 ear, stiffer stalk, and excellent seed quality. 



Number A-13 tomato, a selection from the cross Allred by Rutgers has been 

 sent out for trial in several states and has performed very well in Maine. It has 

 good color and yields well over a long season, but the fruit has a tendency to be 

 soft. This tomato has been back-crossed to Rutgers in an effort to recover more 

 size and solidity. 



A number of sweet pepper selections have been made which have excellent 

 type and are particularly resistant to tobacco mosaic. Further testing is neces- 

 sary to evaluate these selections. 



