58 Bulletin 332 



old tree and the unsprayed portion of the old tree served as checks. 

 Frequent observations were made of these trees during the period 

 between the bursting of the leaf and the fruit buds and to full 

 blossom and, so far as could be observed, no injury was found on 

 any of the trees. Similar experiments were conducted on March 

 18, 1918, with fish-oil soap, 1 pound to 6 gallons of water, plus 

 cresol U. S. P. 2 per cent (2 parts to 98 of solution), and again 

 no injury could be detected. On the basis of the above experi- 

 ments, apparently one can safely apply on dormant trees a spray 

 composed of 2 per cent crude carbolic acid plus fish-oil soap. 



Various Chemicals 



Sodium sulfo-carbonate having a specific gravity of 35° Baume 

 was tried in one set of experiments (G-3, G-76 and G-77, table -1). 

 The effect of this material on the eggs is similar to that of dormant 

 strength lime-sulfur. The proportion of hatched eggs was 15.3 

 per cent with a 1-19 dilution, and 2.6 per cent with a 1-9 dilution, 

 while the check showed 62.8 per cent hatched. These results are 

 similar to those obtained when lime-sulfur was used, and it is 

 possible that sodium sulfo-carbonate as a spray might be used with 

 as much success as lime-sulfur. 



Sodium chloride (common salt) was experimented with at the 

 rate of 1 gm. to 5 cc. of water on the eggs of A. avencB in the green- 

 house (exp. G-4 and G-75, table 4) and out-of-doors (exp. 0-6 and 

 0-74, table 4) and the proportion of hatched eggs was somewhat 

 lower among the sprayed eggs than in the respective cheeks. This 

 shows that sodium chloride may prevent the less resistant eggs from 

 hatching. Common salt in combination with lime-sulfur apparently 

 does not materially increase or decrease the effectiveness of the 

 lime-sulfur spray, according to the results in experiments G-17, 

 0-20 and 0-21 (table 4). 



Sodium hydroxide at the rate of 2 gm. to 98 cc. of water has 

 a decided influence on the percentage of hatch of the eggs of 

 A. avencB in the greenhouse and out-of-doors. In experiments 0-72 

 and 0-7;} (table 4) the proportion of hatched eggs was reduced to 

 9.6 per cent and 1.8 per cent, respectively. A 2 per cent solution 

 has a decided caustic effect which is particularly noticeable if the 

 material is allowed to remain on the bare skin of one's hand. No 

 experiments were conducted with this material on trees during the 

 dormant season; consequently, its effect is unknown. 



Pyridine (10 cc.) combined with xylene (10 cc.) and resin 

 (enough to make 25 cc. of solution) is a very effective mosquito 

 larvieide, so this mixture was given a trial. In experiment 0-78 

 (table 4) where the above mixture was used at the rate of 2 parts 

 to 98 of water plus enough soap to make the spray spread well. 



