Strawberry and Greenhouse Pests. 183 



As the caterpillars feed on the under sides of the leaves, they are 

 not easily poisoned. In the horticiiltnral greenhonses it has been 

 found i)racticable to spray infested geraniums and chrysanthemnms 

 with Paris green, and many caterpillars were killed in this way ; 

 such a spray is not often practicable on many of the other plants 

 attacked by the insect. 



When a lighted lantern has been carried into the horticultural 

 greenhouses, it has been noticed that some of the moths of this pest 

 were attracted and would flutter about the lantern. A pan of water 

 with a little kerosene oil on its surface was placed in an infested 

 house one night, and a lighted lantern was set on a block in the 

 center of the pan. The weather conditions were such that the moths 

 were not at all active during the night, and but two of them were 

 caught in this trap-lantern. More would doubtless have been caught 

 on a more auspicious night, so that such a trap-lantern is worthy of 

 further trial, and it may materially help to control the pest in some 

 cases. 



The infested greenhouses have been frequently and successfully 

 fumigated with tobacco, either as stems, or "rose-leaf extract" for 

 other pests like plant-lice and the " white-fly," but the ravages of 

 the greenhouse leaf-tyer were not checked. Another very expensive 

 tobacco-like insecticide known as " nicoticide " was used with appar- 

 ent success against the leaf-tyer in a small greenhouse, but when 

 used in commercial quantities in a large house it failed to kill the 

 insect. 



In his book on Commercial Violet Culture Galloway states that 

 where greenhouses are fumigated with hydrocyanic acid gas for 

 other pests, this leaf-tyer also is easily kept in check. And other 

 reports of the successful use of this deadly gas in killing such green- 

 house pests as plant-lice, scale-insects, mealy-bugs and " white-flies " 

 led us to believe that it would be a simple matter to exterminate the 

 leaf-tyer with this gas. But circumstances were such that the gas 

 was only recently tested. A large infested greenhouse (about 8,000 

 cubic feet space) was fumigated with the gas at the rate of 1 ounce 

 of cyanide to each 400 cubic feet of space for about half an hour ; 

 this is about half the strength recommended for other insects. Two 

 live moths of the leaf-tyer in a wire cage were not killed by the gas, 



