346 



GREENHOUSE INSECTS. 



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



White-fly. underside of the leaves; the adults are minute, white, mealy 



winged flies. Spray with kerosene emulsion or whale-oil soap; 



or if infesting cucumbers or tomatoes, fumigate over night with hydr9cyanic acid 



gas, using i oz. of potassium cyanide to each looo cubiC|feet of space. 



Spray with kerosene emulsion when practicable, or fumigate 



Green aphis, with. one of the tobacco preparations. If on violets, fumigate, 



using i to J oz. potassium cyanide for every looo cu. ft. of space 



and leave the gas in from J to i hour. 



Black anhis '^^^ plant-louse is harder to kill than the green aphis, but may 



' be controlled by the same methods. 

 Red-spider. Syringe ofE the plants with clear water two or three times a week, 

 taking care not to drench the beds. 



Violets grown under glass are often greatly injured by a very 

 Violet gall-fly. small maggot, which causes the edges of the leaves to curl, turn 

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

 mosquito. Pick off and' destroy infested leaves as soon as dis- 

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



III. INSECTICIDES. 



M. V. SLINGERLAND AND C. R. CROSBY. 



This can be applied in a stronger mixture than other arsenical 



Arsenate poisons without injuring the foliage. It is, therefore, much 



of lead. used against beetles and other insects that are hard to poison. 



It comes in the form of a paste and should be mixed thoroughly 



with a small amount of water before placing in the sprayer, else the nozzles will 



clog. Arsenate of lead and Bordeaux mixture can be combined without lessening 



the value]|of either. It is used in strengths varying from 4 to 10 lbs. per 100 gals., 



depending on the kind of insect to be killed. 



This is used in varying strengths, depending on the insect to be 

 Paris green, controlled and the kind of plant treated. Mix the Paris green 

 into a paste and then add to the water. Keep the mixture 

 thoroughly agitated while spraying. If for use on fimit trees, add i lb. of quick 

 lime for every pound of Paris green to prevent burning the foliage. For potatoes 

 it is frequently used alone, but it is much safer to use the lime. Paris green and 

 Bordeaux mixture may be combined without lessening the value of either and the 

 caustic action of the arsenic is prevented. 



(For use with Bordeaux mixture only). Sal soda 2 lbs.; water 



Arsenite i gal. ; arsenic i lb. Mix the white arsenic into a paste and then 



of soda. add the sal'soda and water and boil until dissolved. Add water 



to replace any that has boiled away so that i gallon of stock 



solution is the result. Use i quart of this stock solution to 50 gallons of Bordeaux 



mixture for fruit trees. Make sure there is enough lime in the Bordeaux mixture 



to prevent the caustic action of the arsenic. 



