PROTECTING PLANTS 207 



turn yellowish, and die. The adult is a very minute fly resembling a 

 mosquito. Pick off and destroy infested leaves as soon as discovered. 

 Fumigation is not advised for this insect or for red-spider. 



White-fly. — The minute white-flies are common on greenhouse 

 plants and often in summer on plants about gardens near greenhouses. 

 The nymphs are small greenish, scale-like insects found on the under 

 side of the leaves ; the adults are minute, white, mealy-winged flies. 

 Spray with kerosene emulsion or whale-oil soap ; or if infesting cucum- 

 bers or tomatoes, fumigate over night with hydrocyanic acid gas, 

 using 1 oz. of potassium cyanide to each 1000 cu. ft. of space. (See 

 page 188.) 



White grubs. — The large curved white grub'fe that are so trouble- 

 some in lawns and strawberry fields are the larvae of the common June 

 beetles. They live in the ground, feeding on the roots of grasses and 

 weeds. Dig out grubs from beneath infested plants. Thorough early 

 fall cultivation of land intended for strawberries will destroy many of 

 the pupse. In lawns, remove the sod, destroy the grubs, and make 

 new sward, when the infestation is bad. 



Treatment for some of the common plant diseases. 



The following advice (mostly adapted from Whetzel and 

 Stewart) covers the most frequent types of fungous disease 

 appearing to the home gardener. Many other kinds, however, 

 will almost certainly attract his attention the first season if he 

 looks closely. The standard remedy is bordeaux mixture; 

 but because this material discolors the foliage the carbonate of 

 copper is sometimes used instead. The treatments here recom- 

 mended are for New York; but it should not be difficult to 

 apply the dates elsewhere. The gardener must supplement all 

 advice of this character with his own judgment and experience, 

 and take his own risks. 



Apple scab. — Usually most evident on the fruit, forming blotches 

 and scabs. Spray with bordeaux, 3-3-50, or lime-sulfur, 1-40 ; first, just 

 before the blossoms open; second, as the blossoms fall; third, 10 to 14 



