34 MASS. EXPERIMENT STATION BULLETIN 293 



flies emergcil from overwintered pupae confined at 85° and only 44 per cent 

 emerged at 75° E. The average date of emergence was LS days later at 55° than 

 at 75° F". Adults lived longest at 55°, and the largest number of eggs was laid at 75°, 

 but 65° appeared to be the most favorable temperature for normal development. 



In the field plantings there was no first generation injury in the untreated check 

 and only one in 2050 carrots examined showed severe injury. The normal field 

 infestation by the second generation was about 10 per cent most of which was 

 slight and moderate, rather than severe. Celeriac was free from injury in compari- 

 son to other years when this plant suffered moderate to severe damage. Among 

 new varieties of carrots which were observed for susceptibility. Table Gem and 

 Tendersweet showed a tendency toward injury in spite of the light infestation. 

 Under the existing conditions, broadcasted applications of tobacco dust and soot 

 were very satisfactory when applied three times at weekly intervals, although the 

 plots receiving two applications of these materials showed about the same infesta- 

 tion as the untreated check. 



Influence of Temperature on Development of Red Spider. (W. D. 



Whitcomb.) The abundance of the red spider on greenhouse plants increased 

 with the temperature, and on cool-growing plants such as carnation, injury by 

 this pest can be reduced to a minimum by maintaining temperatures near 50° F. 

 during cool weather. In experiments at 50° E. development of the younger stages 

 was not complete, although some eggs were exposed for 57 days before it was de- 

 termined that they would not hatch. The average number of days required for 

 development from the newly laid egg to the adult was 29.1 at 60°', 12.4 at 70°, and 

 7.0 at 80° F. Eggs were hatched in 11.72, 5.35, and 3.53 days at the higher temp- 

 eratures respectively, and over 90 per cent of the eggs hatched at these temp- 

 eratures. 



Although red spider eggs do not hatch at 50° F., there is a slight biologic devel- 

 opment at this temperature which causes hatching in less than the normal period 

 when the eggs are transferred to more favorable temperature. This biologic 

 development varies directly with the length of exposure at 50° F. 



DEPARTMENT OF FARM MANAGEMENT 

 J. A. Foord in Charge 



Enterprise Relationships and Farm Organization on Selected Dairy 

 Farms in Massachusetts. (R. L. Mighell.) Studies of the effect of replanning 

 the labor program and the internal organization of enterprises on dairy farms 

 have been continued. It has been discovered that significant savings in labor 

 can be made in many farm tasks, for e.xample daily chores, by means of careful 

 planning. Frequently an inexpensive piece of equipment, or slight change in 

 routine, will result in a considerable reduction of labor time. P^or e.xample, on 

 one farm the installation of an 18-foot extension of pipe line made a net saving 

 in chore time of 13.4 minutes daily or more than IJ hours per week. 



Types of Farming in Vegetable Garden Areas. (R. L. Mighell, J. E. 

 Thigpen. Cooperative with the E-xtension Service.) Records secured in the 

 1930 season have been further analyzed, and the amounts and distribution of 

 labor used on different vegetable crops presented in tabular and graphic form for 

 use in giving a more accurate picture of the types of farming in vegetable areas 

 and in planning more profitable crop combinations. Variations in amounts of 

 labor used for the same operations have furnished the starting point for the study 

 of labor-saving methods and technicine. 



