31 



them. The species experimented upon were Yellow Canker-worms 

 {Hibernia tiliaria, Harris). They were placed on a wire screen so 

 that the water could not collect around them, and the water was 

 applied to the same lot of worms only once ; the latter were kept 

 out of the direct rays of the sun. The water was heated to 100°, 

 110", and so on up to 140". 



At ISO"" it was applied to twelve of the worms, and at 140° to ten ; 

 but it did not kill any of them, as they were all alive the second 

 day after making the experiments. As soon as the water touched 

 the worms of the latter lot they squirmed around considerably, and 

 had the water been heated to 150° it would very probably have 

 proved fatal to them, but it would have injured the plants, except 

 such as were hardier than the plants which I experimented upon. 



A more effectual remedy than this, but one that we are slow to 

 recommend, is to dust the infested plants with a mixture of Paris 

 green or London purple and fine road dust. This remedy is strongly 

 recommended by a prominent market-gardener of Danville, Illinois, 

 who, in a communication to the Germantown Telegraph, of July the 

 13th, 1881, after referring at some length to the question of a remedy 

 for the Cabbage worms, says : 



"We tried every remedy known and unknown, but without avaiL 

 Our cabbages would be defoliated in spite of them. But our atten- 

 tion has been called to a new means for their destruction, which has 

 proved a perfect success when intelligently applied. We give it to 

 you with some hesitation, knowing the popular fear that may arise 

 from its use. Bat we have no hesitation now to declare it perfectly 

 innocent to health, after using the vegetable freely on our tables, 

 and finding no complaints from the quantities we have marketed. 

 Our remedy is the assenated lime, commonly known as London 

 Purple. This strange substance is the residuum from the great stills 

 of the manufacturing chemists, in obtaining analine dyes from coal- 

 tar, and contains a small amount of arsenous acid with a large 

 quantity of silicate of lime and coloring matter of a beautiful rich 

 purple — the rich purple which is now superseding graphite in the 

 manufacture of pencils. We mix this substance with any fine dry 

 dust, the finer the better. Dust from clayey roads is excellent. We 

 proportion about one-fourth pound of purple to twenty-five pounds 

 of dust, and to more thoroughly incorporate it, pass it all through 

 a meal sieve. We have now our remedy. We take a still day when 

 the plants are perfectly dry. We carry a dish of the dust in our 

 left hand and dash a pinch of it in the heart of the plant with our 

 right. The air being so still and the dust so fine, it will fog through 

 all the convolutions and folds of the leaves, settling on the soft, 

 clammy bodies of the larvae, and in the course of ten or fifteen 

 hours they give up the ghost. Two or three applications in a sea- 

 son are sufficient. The materials will wash away by rains, and the 

 plant, unfolding from its center, ' brings on new growth, so that no 

 more fear may be apprehended in using it than on potatoes. On 

 the latter we use it in the same way, doubling the strength, and 

 apply when the dew is on the vines. The larvte of the Colorado 

 beetle are easily killed this way, and more effectually than by water 

 mixtures. A. R." 



