134 



DISEASES OF CROPS. 



Prevention. — (1) Sprinkling the plants with soot causes 

 both larvae and beetles to make a retreat from the as- 

 paragus beds. (2) Syringing the infested plants with 

 warm water has also been recommended for the same 

 purpose. (3) Dressing asparagus beds in the spring with 

 salt and quicklime greatly lessens the attacks of this pest. 



Cure.—{1) In the United States " Paris green " (the 

 poisonous copper arseniate) has been effectually used as 

 a remedy against the attacks of C asparagi. The " Paris 

 green " is suspended in water (| lb. to 40 gallons), and the 

 asparagus beds are watered with 40 gallons of the mixture 



Fig. 46. 



per acre (Eiley's Insect Life, vol. i. p. 110, and The 

 Fourth Report of Entomological Commission, U.S.A., 

 p. 143). (2) The author has found that a small quantity 

 of crude or commercial naphthalene placed along the rows, 

 followed by syringing the infested plants with cold water, 

 completely destroys both the larvae and beetles. 



(2) The Parasites of Cabbage {Brassica oleracea) 

 AND Allied Crops. 



(a) The Large White Butterfly (Pontia brassicce, 

 Pieris brassicce). These butterflies " hover over the beds 

 of cabbages and lay their eggs on the leaves. The eggs 

 are small yellowish bodies (Fig. 46 A) somewhat re- 



