28 MASS. EXPERIMENT STATION BULLETIN 293 



The Comparative Efficiency of Electrically-operated Tanks versus Ice 

 in the Cooling of Milk. (J. H. Frandsen.) A study of the efficiency of various 

 methods of cooHng milk, as practiced under actual farm conditions, is now in prog- 

 ress. The efficiency of most recent electric cooling units is also being studied. 



DEPARTMENT OF ENTOMOLOGY 

 A. L Bourne in Charge 



Investigation of Materials Which Promise Value in Insect Control. 



(A. I. Bourne.) Weather conditions in the early spring of 1932 were favorable for 

 application of oil sprays. There was very little interruption due to inclement 

 weather. Moderately high temperatures prevailed at the time the buds were 

 breaking, and no sudden drops in temperature were encountered sufficient to 

 cause a breakdown of the sprays and consequent injury to the trees from the free 

 oil liberated. No evidence of burn was noted following any of the oils tested. 

 Four oil emulsions and two miscible oils were used in the tests against European 

 red mite. At the dilution of 4 gallons per 100, Kleenup gave 95 per cent control; 

 Free Mulsion, 94 per cent; and Emulso, 92 per cent. Used at the rate of 5 gallons 

 per 100, Kleenup showed 98 to 99 per cent control; Free Mulsion, 98 per cent; 

 and Emulso, 95+ percent. Peninsula Oil Emulsion, a new product on the market, 

 at the strength of 45 gallons to 100 gave 95 per cent control. The miscible oils, 

 Dendrol and Sunoco, maintained their usual high degree of effectiveness, both show- 

 ing 98 -f per cent control at the standard dilution recommended by their manu- 

 facturers. 



The present tendency in the use of oil sprays appears to be toward a com- 

 paratively few of the standard, well-established types which have been in use long 

 enough to demonstrate their safety and eflfectiveness under Massachusetts condi- 

 tions. 



Preliminary tests with various insecticides for the control of the Mexican bean 

 beetle indicated that magnesium arsenate, either as a spray or dust, is at present 

 the safest and most dependable material on the market. Both lead arsenate and 

 calcium arsenate caused severe burning, in most cases killing the plants. There 

 is, however, some evidence to show that they might be used, if necessar}', during 

 the early season when both temperature and humidity are comparatively low. 

 Barium fluosilicate caused a slight amount of foliage burn during midsummer. 

 However, it showed possibilities for use on late string beans when arsenicals would 

 be objectionable because of residue on the harvested crop. Some of the commercial 

 products containing arsenicals combined with a fungicide proved effective against 

 the insects and safe to the foliage of the beans. They are, however, somewhat 

 expensive, especially if used on large plantings. 



In cooperation with the Pomology Department, further studies were made 

 of different "wettable sulfurs" designed to replace lime-sulfur in the midsummer 

 sprays. Tlie object of these tests was to find a spray that would prove effective 

 against scab and compatible with lead arsenate, and at the same time would avoid 

 the foliage burn and russeting of fruit which almost inevitably follows the use of 

 lead arsenate and lime-sulfur in the post-blossom sprays. 



Mulsoid sulfur, Dritomic sulfur and a combination of flotation sulfur and finely 

 divided sulfur were used in combination with lead arsenate. The schedule followed 

 called for a pre-pink, a pink, a calyx, a special curculio and a cover spray and two 

 July applications for railroad worm. The standard lime-sulfur — lead arsenate 

 combination was used on one block, as a basis for comparison. These wettable 



