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UNITED STATES DEPARTMENT OF AGRICUL 

 AGRICULTURAL RESKARCH ADKTNISTRATIO 

 BUREAU OF FJSTTOMOLOGY AND PLANT (&JARANT 

 Forest Insect Investigations 



Forest Entomology ^rief 70 _ Beltsville, Maryland 



{^^November 22, 1950 



■ A SHORT DISCUSSION OF SOKE SCALES AFFECTING SHADS TREES AND HARDY SHRUBS 



Suonymus scale . — The euonymus scale (Un aspis euonymi (Comst . ) ) is a 

 persistent and serious nest of euonymus. It also attacks celastrus and 

 probably pachistima and pachysandra. It is difficult to control, sometimes 

 requiring several years' work: to secure the results desired. The euonymus 

 scale is a problem sufficient to make it questionable whether the planting 

 of euonymus as an ornamental, especially in neighborhoods where the plant is 

 already fairly abundant, is desirable. 



The methods suggested for its control are cutting and burning the dead 

 and heavily infested portions of plants that can be spared without seriously 

 injuring the appearance of the plant, and then spraying the remainder of the 

 plant in the early spring just before new growth commences, using a dormant 

 strength oil emulsion or miscible oil. It would also be a very good plan to 

 watch the plant duiing the growing period for the appearance of the crawlers, 

 or young scales. There are likely to be several generations of these. One 

 may occur around "che middle of Hay, another from the middle to the latter 

 part of Juno } and possibly another group of crawlers late in the summer. When 

 the crawlers are present and abundant, the infested portions of the plants 

 should be given a thorough application of the following spray: 



Nicotine sulfate (40 percent) .... 1-1/4 teaspoonfuls 



Soap flakes . , . 2 rounded tablespoonfuls 



Water 1 gallon 



Dissolve the soap flakes, in warm water before adding the nicotine sulfate. 

 Where there is a heavy infestation of the scale, better control can be had 

 by adding 4 level tablespoonfuls of a white-oil emulsion (83^ of oil) (as 

 Volci-c or Verdol) to the formulation. The white-oil emulsion has the consis- 

 tency of mayonnaise and must be gradually thinned with water before it is 

 added to the other ingredient s_ in the formula. 



Pine-ne edle sc ale. — The pine needle or pine leaf scale ( phenacaspis 

 p inifol iae (Fitch) is frequently found on ornamental pines and on spruce. It 

 is a white scale, shaped like an oyster shell, that adheres very closely to 

 the needles. Control consists of spraying the infested plants and parts cf 

 plants early in the spring just before new growth start' , using one of the 

 "winter oil emulsions or miscible oils. As in the case of the euonymus scale, 

 this scale insect can be combat ted very well by spraying for the "crawlers" 



