U¥ITED STATES DSPARTHSiJT OE AGRICULTUReI S- .:.c-;,c. 



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BUREAU OE ENTOMOLO&Y 

 Washington, D.C. 



Forest Entomolog;y Brief 70 May 1, 1934. 



A SHORT DISCUSSIOiVT OE SOME SCALES AFFECTING SHADE TREES AND HARDI SHRUBS 



Euon:/mus scale - — The euonymus scale is a persistent and serious pest 

 of euonymus. It also attacks celastrus and probably pachistima and pachy- 

 sandra. It is difficult to control, sometimes requiring several years' 

 work to secure the results desired. The euonym.us scale is a problem suf- 

 ficient to make it questionable whether the planting of euonymus as an 

 ornamental, especially in neignborhoods 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 injv.ring the appearance of the plant, and tnen spraying the re- 

 mainder of the plant in the early spring just before new growth comm.ences, 

 using a dormant-strength oil emulsion or miscible oil. It would also be 

 a very good plan to watch the plant during the growing period for the ap- 

 pearance of the crawlers, or young scales. There are likely to be several 

 generations of these. One may occur around the middle of May, another 

 from the middle to the latter part of June, and possibly another group of 

 crawlers late in the sijmmer. When the crawlers are present and abundant, 

 the infested portions of the plants should be given a thorough spraying 

 with a combination of summer oil, soap flakes, nicotine sulphate, and 

 water; or a nicotine sulphate and soap solution. 



Fine needle scale . — The pine needle or pine leaf scale is frequent- 

 ly 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 of plants early in the 

 spring just before new growth starts, using one of the winter oil emulsions 

 or miscible oils. As in the case of the euonymus scale, this scale insect 

 can be combated very well by spraying for the "crawlers" with the summer 

 spray m.aterials suggested above, if a careful watch is kept for the ap- 

 pearance of the yoimg scales. These are usually found during the middle 

 of May, the middle of June, mid-August, and mid-September. 



Juni-per scale . — Juniper, or cedar, and arborvitae are very frequent- 

 ly attacked by a small scale insect technically known as Diasnis carueli 

 Targ. and commonly called the juniper scale. The control of this insect 

 will require the same spray materials and methods suggested for combating 

 the "Dine leaf scale and euonymus scale. It is not certain that this species 

 has as many generations as those treated above, but one group of crawlers 

 will usually be fo"uxLd during the first half of June. 



WILLIA^/I MIDDLETON, 

 Entomologist . 



