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UNITED STATES DEPARTMANT OF AGRICUL AGRICULTURAL RESEARCH ADMINISTRATIO

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BURIAU OF ENTOMOLOGY AND PLANT QUARANTINGE 5 Dey ag Annitt Forest Insect Investigations See Forest Entomology Brief 70 | : Beltsvill e, Maryland

CuriiadNovember zy AUSIEXO) - & SHORT DIS CUSSION OF SOME SCALES AFFECTING SHADE TREES AND HARDY SHRUBS

Euonyms_scale.-- The euonymus scale (Unaspis euonymi (Comst.)) is a persistent and serious vest of euonymus. It also attacks celastrus and vrobably vachistima and pachysandra. It is difficult to control, sometimes requiring several years! work to secure the results desired. The evuonymus scale is a problem sufficient to maxe 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 piants 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 Wateh the Diait during the growing pneriod for the anpearance of the crawlers. Or youn2 seaiscs. Traere are likely to be several generations of these. One May OG2ur around the micale of Mey, anobher from the mic Le To “bhe lativer pace of junc, and possibly another group of icrawlers late in the summer. When the crawlers are Paget and abundant, the infested portions of the plants should be given a thorough aapileabaee of the following spray:

Nilcotime /Suilkragew(40 mercemb\!. sc) eae 6. l-t/4) Feasvoonpulls SONU) jah LENSES CG oo Qh se oun meigh om nchl Cal I ion wagon LC) 2xONDUsIOKSIOh MmellOILes) oxoyoralit WIL} WEITERE CHa i 6 oo | GUNG Bo mG conto s CiLLCw Sim ciins opmo Ni cotaind sabe rexcalsioyal

Dissolve the soad flakss. in warm water before adaing the nicotine sulfate. liteme there ts a sheavy autestation of the sealie, better control can be had by adding 4 level tablespoonfuls of s white-oil umilsion (83% of oil) (as Volek or Verdol) to the formulation. The white-oil emulsion has the consis- tency of mayonnaise and must be gracually thinnec with water before it is adged to the other ingredients inthe fornula.

Pane; eed te yscallles——) Te pine mecdlie ox mime Neat seale (Phenacaspis

pinifoliae (Fitch) is frevuently found on ornamental pines and on spruce. It is a white scale, shaped like an oyster shell, that adheres very closely to the neeclss. 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 evonymus scale, this scale insect can be combatted very weil by spraying for the “crawlers”

with the summer spray materials suggested above, if a careful watch is kept for the appearance of the young scales. These are usually found during the middle of May, the middle of June, mid-August and Mid-September. —

Juniper scale.-- Juniper, or cedar, and arbervitae are very frequently attacked by a small scale insect technically known as Diaspis carueli Targ. ana commonly called the juniper scalc. The control of this insect will require the same ssray materials and methods suggested for combating the pine leaf scale and euonymus scale. It is not certain that this species hés as many generations as those treated above, but one group of crawlers will usually be FOuNnG dunIne the: Lirst halt of june.