662 



STATE BOARD OP AGRICULTURE. 



TABLE 6.— TRANSPIRATION OF LEAFLETS IN EARLY STAGES OF DISEASE: 



PERFORMANCE OF POTOMETERS. 



TABLE 7.— TRANSPIRATION OF LEAFLETS IN LATER STAGE OF DISEASE: 

 MEASUREMENT OF AREAS AND DISEASED SPOTS. 



TABLE 8.- 



-TRANSPIRATION OF LEAFLETS IN LATER STAGES OF DISEASE: 

 PERFORMANCE OF POTOMETERS. 



In the cases where the leaflets were green and spots pliable, (Tables 

 5 and 6), the decrease in rate of transpiration after the vaseline was 

 applied is far greater than the mere decrease in transpiring surface 

 would warrant. Although the spots were on an average only 4.8 per cent 

 of the total leaf surface, the transpiration was cut down nearly one- 

 half (.59) by vaselining the spots. This indicates that in early cases of 

 attack, the diseased spots evaporate more than the healthy portions. 



In the potometers with the yellowed leaves, (Tables 7 and 8), there 



