HANDBOOK OX INSECT ENEMIES OF FLOWERS AND SHRUBS 105 



Table 1. — Quantities of common insecticides to be used in preparing 1. 3. and -50 



gallons of spray 



Materials 



With 1 gallon of water With 3 gallons of water ^* o/water 



LEAD ARSENATE 



Lead arsenate 2$ ourice , or 3i e veltable- 2 ounces, or 9 level table- 2 pounds. 



spoonfuls. spoonfuls. 



NICOTINE SULFATE AND SOAP 



Nicotine sulfate f40 percent nicotine)-.. 1 level teaspoonful 3 level teaspoonfuls Sfluidounces 



pint). 



Soap flakes or cake soap 1 ounce, or 2 level table- 3 ounces, or 6 level table- 3 pounds. 



spoonfuls of flakes, or spoonfuls of flakes, or 



a 1-inch cube of soap. 3 1-inch cubes of soap. 



DERRIS-ROOT POWDER « 



... Yo ounce, or 1H level % ounce, or i 1 ^ level 9 ¥> ounces, 

 tablespoonfuls. tablespoonfuls. 



2 teaspoonfuls 6 teaspoonfuls (2 table- 1 pint. 



spoonfuls. 

 ... H ounce, or 1 level table- h ounce, or 3 level table- 7H ounces. 

 spoonful. spoonfuls. 



Sulfonated castor oil 2 teaspoonfuls 6 teaspoonfuls (2 table- 1 pint. 



spoonfuls). 



Den-is powder (i percent rotenone) . 

 Sulfonated castor oil 



Derris powder (5 percent rotenone). 



1 These dilutions give a rotenone content of about 0.0056 percent in the completed spray. To increase the 

 rotenone content to about 0.02 percent, use approximately 4 times the quantity of derris-root powder indi- 

 cated above but do not increase the quantity of sulfonated castor oil. 



enemy of the plant or is found actually 

 injuring it. Where only a few plants are 

 concerned it may be sufficient to pick 

 off the infested leaves or to remove and 

 kill the insects. 



It should be remembered that only 

 those parts of the plant are protected 

 that are thoroughly coated with mate- 

 rial. Sprays often stick better than 

 dusts and can be applied in light winds. 

 However, dusts are easier to apply, and 

 dusting equipment is less expensive and 

 requires less attention to keep it in 

 working order. For small gardens, 

 therefore, dusting is probably the more 

 satisfactory method. 



To get the best results in the control 

 of insects, the spray or dust mixtures 

 must be properly prepared, and the 

 applications must be made promptly 

 and thoroughly with good apparatus. 

 Disregard of these factors will result in 

 waste of material, possible injury to the 

 plants, and questionable results. Do 

 not wait until the plants are seriously 

 injured, but begin the treatment as soon 

 as damage is observed. Using a water- 

 ing pot or whisk broom is not spraying 

 and is a hit-or-miss method that covers 

 the plants only partially. The ideal 

 spray is a fine mist, and the best work is 

 done when the entire plant is thor- 

 oughly and evenly covered with very 

 fine droplets. With dusts, also, an even 

 and thin coating of the dust particles 

 over the plant surfaces is desired. Best 



results are accomplished by directing 

 the sprays or dusts from below to cover 

 the under surfaces of the foliage and 

 from above to cover the upper surfaces. 

 Stop spraying before the foliage is 

 drenched: otherwise large droplets will 

 form and run off from the plant. 

 Spraying with pressure gives the best 

 results. Keeping the solution agitated 

 while spraying insures a more uniform 

 mixture. 



If one application does not give good 

 control, repeat the treatment as often 

 as is necessary. The interval between 

 applications will depend upon the habits 

 of the insects, the weather, and on 

 plant growth. 



QUANTITY OF SPRAYS OR 

 DUSTS TO APPLY 



For small gardens 1 to 2 ounces of 

 dust mixture or 1 to 2 quarts of liquid 

 spray are usually required for one appli- 

 cation to 100 square feet of garden or to 

 50 linear feet of row. This is roughly 

 equivalent to 25 to 50 pounds of dust 

 mixture or 100 to 200 gallons of spray 

 per acre. Under some conditions the 

 quantity required may be more or less, 

 depending on such factors as the type 

 and size of planting, the insect, the crop. 

 the size of the plants, and the thickness 

 of growth. In extensive plantings 

 small plants in rows 2 or 3 feet apart. 



