310 The Spraying of Plants. 



habits, but it is not red, and it has two dark spots at the rear 

 of the back. 



Treatment. The mite is perhaps the most difficult to over- 

 come of all insects found in the greenhouse. Unlike the red 

 spider, it is but little affected by a moist atmosphere, or by 

 moisture upon the infested parts. If water is forcibly sprayed 

 upon the insects so that they will be dislodged, some good will 

 result. But all plants cannot withstand this treatment. The 

 best method of destroying the mite is probably to use kerosene 

 emulsion containing from twenty to twenty-five parts of water 

 to one of oil, or to apply Antipest, Fir-tree oil, or some other 

 good commercial insecticide of this nature. The insects are 

 most abundant on the under surface of the leaves, and all 

 applications should be carefully and forcibly directed to these 

 parts. The plants should be sprayed once or twice a week, and 

 the foliage of some should be washed or syringed an hour or 

 two after the treatment, to prevent injury from the insecticide. 



Red Spider (Tetranychus telarius, Linn.). Description. The 

 red spider is a true mite, and not a spider. It has received the 

 name from the fact that it spins a web, and covers the leaves 

 and even whole plants with an envelope of irregularly but 

 thickly scattered silken threads. It sucks the juices of the 

 host-plants, preferring the more tender green parts for the 

 scene of operations, although older foliage does not escape its 

 ravages. The red spider causes the color of the leaf to change 

 from green to a grayish-white, which shows very plainly upon 

 most plants. This whitening of the upper surface of the 

 foliage is a certain indication of the presence of a sucking in- 

 sect, and generally this insect proves to be either the red spider, 

 the mite, or thrips. The last, however, does not form a web. 

 Such discoloration should be immediately investigated, and if 

 either of the first are present, the careful gardener will remove 

 the parts and take precautions to destroy any insects which 

 may escape this process. 



Treatment. The red spider nourishes in a dry atmosphere 

 and in bright, sunny places ; shade and moisture are unfavor- 

 able to its development. Here, then, lies the secret of its cheap 

 and successful destruction. Copious spraying of the affected 

 parts with clear water, and the maintenance of a moist atmos- 

 phere, will soon rid a house of this insect ; in case such a course 



