394 BOARD OF AGRICULTURE. [Pub. Doc. 



Dipping. 



Dipping wherever this is possible is much better than spraying, as 

 the entire plant is reached, while this is practically impossible by 

 spraying. As only potted plants can be dipped, however, it is often 

 necessary to resort to spraying instead. 



Tobacco water, made by steeping tobacco leaves and stems in hot 

 water, is a good insecticide for plant lice, mealy bugs and thrips, but 

 weak solutions are far from effective. The use of laundry soap also gives 

 good results, though for many plants more than four ounces per 

 gallon of water is not safe for the plant, while ineffective against the 

 insects. As a general thing, though, it would be well to try the soap 

 before resorting to tobacco water. 



For scale insects laundry soap is usually too weak to be of much 

 value, and whale-oil soap must be used. Fortunately, most cycads, 

 palms and citrus plants can withstand this when used even as strong 

 as one pound per gallon of water, though ferns are injured by such 

 a strong solution. 



To dip potted plants rapidly, a tall can filled with the soap is a 

 great convenience, particularly if as tall as are the plants to be dipped. 

 Turn the plant bottom up and plunge it into the can till the wash 

 reaches the bottom of the stem, and hold it there a few moments, 

 then remove it and let it drain before putting it back in its place. In 

 some cases it may seem advisable to wash the plant with clean water 

 after a few hours. 



For red spiders, fumigation with tobacco or hydrocyanic acid gas 

 is at best only partially successful. But where the plants can stand 

 it, flowers of sulfur, mixed with water at the rate of an ounce to a 

 gallon, sprayed over them is quite effective. With plants affected 

 by the sulfur it has been found that a 5-cent cake of castile soap 

 dissolved in about six gallons of water forms a spray which gives 

 good results. This spray should be allowed to stay on the plants 

 for two or three hours, after which it should be removed by syringing 

 with clean water. Two or three treatments with castile soap in this 

 way will greatly reduce the number of the red spiders. In some 

 cases drenching the plants thoroughly with a solution of two ounces of 

 salt in a pailful of water has proved quite successful. 



