40 



Kerosene emulsion and whale-oil and other soap solutions are also 

 valuable, and the addition of the sulphur increases their effectiveness: 

 but these washes are too strong for some plants and are apt to injure 

 them. 



For the particular red spider in question, as it occurs in greenhouses, 

 particularly on plants that are liable to injury by the use of sulphur*, 

 such as violets, no other remedy is used by florists generally than fre- 

 quent syringing or spraying with water or with a solution of neutral 

 soap. Both have been extensively used by Mr. Galloway in growing 

 violets, from whose experience the following instructions have been 

 gathered: 



Neutral soaps, such as castile soaps, are particularly valuable for 

 use upon cuttings affected with red spider, and the best results have 

 been obtained in using such at the rate of a 5-cent cake to 6 or 7 

 gallons of water. The soap is shaved with a small plane, dissolved 

 in about a gallon of hot water, and then sufficient cold water is added 

 to make the quantity desired. Five gallons are sufficient for the treat- 

 ment of three or four cuttings of violets, and other plants are in pro- 

 portion. It is customary to allow the soap to remain on the plants two 

 or three hours, and then thoroughly syringe with clear water, repeat- 

 ing this treatment two or three times until the spiders and their eggs 

 have been destroyed. Used in this way, the soap has little if any 

 deleterious effect upon most greenhouse plants. 



It is unsafe to use strong soaps, such as potash, whale-oil. or fish-oil 

 soaps, as they are apt to injure delicate plants and are of no more value 

 as insecticides than those of a neutral nature. 



Tobacco water is of some use for the same purpose, but can not be 

 recommended for violets owing to the tendency which tobacco has to 

 weaken the foliage and induce °\spot." 



Spraying with water is usually practiced from two to three times a 

 week during the growing season, and by a little practice and experi- 

 ment with a fine spray nozzle or tip the operator will soon be able to 

 ascertain the proper degree of force to use. A pressure of about 2o 

 pounds has proved most effective against this red spider. Care should 

 be exercised to wash off the spiders and at the same time not to drench 

 the beds. When it is necessary to spray during the winter time work 

 should be done on a bright day in order that the plants may dry off 

 in a few hours. 



Spraying apparatus. — For several years the want has been felt by 

 fforists of a spraying apparatus that would be perfectly satisfactory 

 for use in greenhouses, and that could be purchased at a moderate 

 price. Such a sprayer has been devised by Mr. Galloway, and the 

 illustration here presented (fig. 12) shows its general appearance. It 

 will be seen that it is an ordinary hand syringe fitted with a Vermorel 

 nozzle and provided with a separate intake attachment. 



