30 MASS. EXPERIMENT STATION BULLETIN 305 



to foliage. Little russeting of fruit was noted, however. None of the other 

 combinations caused foliage injur\-. 



The value of these materials in controlling disease and insect pests is shown 

 in the following table, based on examination of the Mcintosh crop at harvest. 



Percentage Percentage of Fruit Showing 

 Treatment of Clean Injury From: 



Fruit 



Curculio Codling Moth Scab 



Lime-sulfur 82.7 9.0 4.5 .4 



Lime-sulfur 1 



Lime ..../■ 90-6 -5 1-6 6.7 



Sulcoloid (entire season) 50.2 .9 2.0 47.0 



Sulcoloid (after lime-sulfur) 55.9 .6 6 41.3 



Apple Dritomic (entire season) 49. 2 .6 T 47.4 



Apple Dritomic (after lime-sulfur) 87.7 1.1 .6 8.5 



Magnetic Spra^" 



T • ,r f> 94.1 T 19 1.5 



Lmie-sulfur I 



Kolofog (entire season) 84. 1 — T 14.8 



Kolofog (after lime-sulfur) 89.1 .4 1.0 8.0 



Flotation sulfur (entire season) 98.1 .3 .3 .9 



Flotation sulfur (after lime-sulfur) 96.3 .4 1.4 .8 



Check 1.1 49.6 13.9 92.4 



The addition of hydrated lime to the standard lead arsenate-lime-sulfur com- 

 bination gave a greater percentage of clean fruit and less insect damage than when 

 this material was omitted. It did not hold scab as well as did the combination 

 without lime. 



Sulcoloid and Apple Dritomic combined with lead arsenate proved rather 

 disappointing in control of scab. The control of insects by these combinations 

 was excellent and but for the large amount of scab present both of these materials 

 would have allowed over 90 per cent of clean fruit. In fairness to these materials 

 and their manufacturers, it should be stated that during the application of the 

 pink spraj' a heavy rain interrupted the spraying, and these two materials had 

 to be applied the day following the rain. This rain marked one of the first 

 periods of scab infection and the delay of one day in applying these spra\"s allowed 

 infection to take place. The materials merit further tests. 



The combination of magnetic sulfur — lime-sulfur — lead arsenate gave ex- 

 cellent control of both insects and scab and allowed 94 per cent of clean fruit. 

 Kolofog again showed to better advantage when it followed lime-sulfur in pre- 

 blossom sprays. Flotation sulfur gave excellent results, with a slight advantage 

 in favor of the use of lime-sulfur in the sprays before the calyx. 



Even a casual glance at the record of the fruit from the unsprayed checks 

 should answer the question, "Does spraying pay?" 



Control of Onion Thrips. (A. I. Bourne.) Onion thrips were more abundant 

 in 1933 and the infestation more uniform than for several years. Observations 

 throughout the Connecticut Valley during the growing season revealed heavy 

 infestations of fields of seed onions well isolated from sets, a condition that 

 differed greatly from experience in previous seasons. 



