116 THE EEPOET OF THE No. 36 



ing upon the injury he referred specially to the destruction of the growing tips of 

 the fronds before they unroll (see fig. 7, page 112). 



On May 10 I visited Mr. Barton's greenhouses and examined his stock of 

 ferns which had been attacked by the caterpillars. They were, indeed, an un- 

 saleable lot, the fronds of most of them being eaten to a greater or less extent and in 

 many instances the plants almost entirely defoliated. Many had been des- 

 troyed to the extent shown in figure 6, page 113. Mr. Barton informed me 

 that when the outbreak was at its height from three to a dozen lavYve could be 

 shaken from a plant growing in a 5-inch pot. A l.irge stock, particularly of Boston 

 ferns, were in the houses, very few of which had been sold during the entire winter. 

 Mr. Barton estimated that his loss would easily total one thousand dollars. 



When not feeding the cnterpillars rested on the stems chiefly towards the 

 base of the plants. The moths being nocturnal in habit are seldom seen during 

 the day time. 



On j^ovemljcr 4, 1916, I again visited Mr. Barton and found that the insect 

 had re-appeared in the greenhouse. The latest month in spring during which cater- 

 pillars were found in the greenhouse? was June. During the summer 2,500 ferns 

 were placed outside in a cold frame, no ferns being kept in the greenhouses during 

 the summer of 1916. About tlie middle of August the caterpillars were noticed 

 to be destroying the ferns in the cold frame. About 2,000 ferns, in fact, were so 

 badly infested that they were destroyed. The remaining ferns from the cold 

 frame were brought into the greenhouse about October 1st and it was on these 

 plants that the caterpillars were feeding at the time of my visit on ISTovember -4. 



Towards the end of 'N"ovember, 1916, Messrs. Hall and Robinson, Montreal 

 West, Que., informed us that they also observed the caterpillars feeding outside 

 in a cold frame, the plants attacked being Holly Ferns and also Pieris albolineata 

 and P. winsetti. 



Means of Control. 



Tlie following methods of control were adopted m the Weston greenhouse; 



Tobacco Smoke. In January fumigation with tobacco smoke was tested twice 

 within twenty-four hours, the strength in each experiment being two pounds of 

 tobacco stems to 16,000 cubic feet of space. At the time of the fumigations many 

 larvffi were present. Two days later Mr. Barton could not find a single caterpillar, 

 dead or alive, and he thought at the time that the fumigation had proved entirely 

 successful. Later (February 24, 1916), however, the caterpillar re-appeared, but 

 he reported that such fumigation would not be then possible owing to the fact that 

 the houses contained many small seedlings. 



HandpicJcinri. Large numbers of the larviB were destroyed by handpicking 

 in the Weston house. On occasions the pots were shaken individually and the 

 caterpillars which dropped immediately destroyed. In the United States, also, 

 this rather laborious method has been successfully used. When the shaking is 

 done over the ground the caterpillars a.re simply crushed with the foot as they 

 fall. 



As mentioned above the moths are nocturnal- in habit. Oftentimes specimens 

 may be disturbed in the house or may be attracted to a bright light hung in the 

 evening near infested plants. An endeavour, of course, should be made to des- 

 troy all specimens seen. 



Arsenate of Lead. Experiments with arsenate of lead did not prove success- 

 ful. Two sprayings at the strength of one-half pound of arsenate of lead to ten 



