THE IMPORTED CABBAGE WEB WORM. 39 



September 7 the plants in two seed beds and 495 older plants were 

 sprayed. One seed bed contained plants from 1 to 3 inches in height, 

 many of which were infested by small webworms. They had not en- 

 tered the bud, but were working in folded leaves. 



The second bed contained larger plants ready to transplant and 

 only slightly infested. The few larva? present were mostly in small 

 folded leaA^es or occasionally in a bud. The 495 plants had been 

 transplanted for some time and varied from small plants, which had 

 made little growth, to a few which had just begun to head. In 

 fully one-fifth of these plants the bud had been destroyed by web- 

 worms, making the plants worthless. 



In this experiment the plants were simply wet from above. In 

 the seed beds the entire upper surface of the plants was wet. but 

 with the larger plants only the leaves at the center were reached. 

 The mixture adhered very well. At the time of the application all 

 the larva? were concealed in the folded leaA^es or buds. The weather 

 was hot and clear. 



In the seed bed containing the small plants a few larva? were 

 dead the following day (September 8). They were found clinging 

 and exposed on the surface of the leaves. 



The plants sprayed in the second seed bed had been removed and 

 transplanted. The infested ones were discarded, and as a result the 

 effects of the treatment could not be determined. 



In the large plants the larva? were buried beyond the reach of the 

 poison and none were killed. 



September 9 it was noted that a few additional larva? had died in 

 the first seed bed. Some of the leaves were slightly burned by the 

 arsenical. On the old plants no effect was apparent, either upon the 

 larva? or upon the foliage. 



A heavy rain occurred September 10 which washed the poison 

 from the plants : and the experiment was closed on that date. 



As a result of this treatment only a moderate number of larva?, 

 in the folded leaves on the young plants, were killed. With the 

 large plants no larva? Avere killed. All things considered this ex- 

 periment must be rated as a failure. 



Experiment No. 2. — Paris green, 5 pounds; lime, 5 pounds; and 

 whale-oil soap, 10 pounds, in 100 gallons of water. 



September 12 a seed bed of small, well-infested plants was sprayed. 

 The larva? were practically all in folded leaves and only one was 

 found entering the bud. The spray mixture adhered perfectly and 

 the surface of the leaves was thoroughly coated with the poison. The 

 weather was cloudy and sultry. 



A shower occurred the following day, but the poison was not 

 washed from the leaves. No dead larva? could be found at this time. 

 Some of the leaves were slightly burned. 



