ANNUAL REPORT, 1946-47 59 



ternut squash was 29 percent at the end of 14 weeks. The greatest loss occurred 

 in the first two weeks. Dipping the squash in a wax emulsion at harvest or two 

 weeks later reduced the loss to 17.5 percent. Squash placed in a refrigerator at 

 35° F. showed very little loss in weight and kept for three to four weeks, but rot 

 was general and complete at the end of six weeks. Other low-temperature con- 

 ditions will be tested in an effort to find a means of cutting the loss on Butternut 

 squash intended for short storage. 



Weed Control in Vegetable Crops. (William H. Lachman.) The use of Stod- 

 dard Solvent as a weed killer in fields of carrots and parsnips has increased greatly 

 during the past year. A survey made during 1946 revealed that about 1000 

 acres were kept free of weeds by this method in Massachusetts alone. 



Briefly, the method consists of spraying undiluted Stoddard Solvent on weedy 

 carrot fields at the rate of 100 gallons per acre when the carrot plants have de- 

 veloped one to four true leaves and while the weeds are snail; that is, not more 

 than two inches tall. Best results are obtained when the oi is appli.'d with a nozzle 

 that delivers a flat-fan spray at 75 to 100 pounds pressure. Hand weeding has 

 been eliminated except where ragweed is prevalent. For some unexplained 

 reason, ragweed is not killed along with the other weeds. 



Susceptible plants are killed very rapidly. They begin to wilt a few minutes 

 after spraying and are dead within two or three days. The spraying usually 

 results in a slight over-all bleaching effect on the green color in the carrot plants. 

 This does not appear to be associated with any damage to the plants, and the 

 darker color that is characteristic of unsprayed plants usuall}' returns within 

 ten days. 



Sometimes one or more of the older leaves in the outermost whorl of young 

 carrot plants were rather seriously scorched or burned as a result of spraying 

 with Stoddard Solvent. It has been rather definitely established that this dam- 

 age was most apt to occur after the plants had been sprayed while wet from a 

 rain or heavy dew. Repeated tests indicated that the yields of sprayed carrots 

 were not affected adversely, and there was no apparent differential susceptibility 

 among sixteen varieties and strains that had been sprayed three times with oil. 

 Consumers often complain that California-grown carrots taste of oil, but we 

 have had no rejections of sales nor adverse comment from 1500 acres grown and 

 sprayed with oil in Massachusetts during the past two years. 



Of the various Umbelliferous crops tested, carrots displayed the greatest re- 

 sistance to damage from Stoddard Solvent, but even carrots are damaged when 

 sprayed after the roots attain a diameter of J^ to J^ inches. When sprayed after 

 this stage the oil often destroj's the heart of the plant and may envelop the core 

 of the root. Parsnips were sprayed with relative!}' little injury up to the 4-leaf 

 stage, but they were badlj- injured when sprayed in later stages of development. 

 Sm^all celery seedlings grown out-of-doors were resistant to Stoddard Solvent 

 but were damaged beyond recovery when sprayed after the 2-leaf seedling stage. 

 Parsley', fennel, carawa^^ coriander, dill, celeriac, and parsnip-rooted parsley 

 were also resistant to the oil in their early growth stages. 



Injury to the growing point of various Umbels from Stoddard Solvent seems to 

 be associated with the development of the characteristic hollow or groove on the 

 top side of the petiole which directs the flow of oil down to the growing point of 

 the plants where the rate of evaporation is low, and here the oil damage is at the 

 maximum. 



Stoddard Solvent killed such crops as beets, spinach, beans, corn, cabbage, 

 lettuce,- and onions, except where it was applied to the ground before the plumules 



