Several scale insects infest the plum. Chief of these is the dreaded San José scale[190] (_Aspidiotus perniciosus_ Comstock) known and feared by all fruit-growers in the United States. The lime and sulphur solution is now the most common and probably the most effective spray for this insect. The European fruit lecanium[191] (_Lecanium corni_ Bouche) occasionally does a great deal of damage in New York and now and then destroys the whole crop in an orchard. The winter treatment for San José scale is used to control this pest, but usually such treatment is supplemented by a summer spray about July first with such contact sprays as whale oil soap and kerosene emulsion. Of the other scales[192] which feed upon plums and now and then become pestiferous the following may be named: The fruit pulvinaria (_Pulvinaria amygdali_ Cockerell), the mealy bug (_Pseudococcus longispinus_ Targioni), the scurfy scale (_Chionaspis furfura_ Fitch.), the West Indian peach scale (_Aulacaspis pentagona_ Targioni), the Putnam scale (_Aspidiotus ancylus_ Putnam), the cherry scale (_Aspidiotus forbesi_ Johnson), the walnut scale (_Aspidiotus juglans-regiæ_ Comstock), Howard’s scale (_Aspidiotus howardii_ Cockerell), the European fruit scale (_Aspidiotus ostreæformis_ Curtis), the red scale of California (_Chrysomphalus aurantii_ Maskell), the oyster-shell scale (_Lepidosaphes ulmi_ Linnaeus), and the soft scale (_Coccus hesperidum_ Linnaeus). Wild plums of several species seem to be favorite feeding grounds for the tent caterpillar[193] (_Malacosoma americana_ Fabricius), but cultivated plums are not so often attacked; the spraying with arsenites usually given for the curculio is fatal to this pest as well. The spring canker-worm[194] (_Paleacrita vernata_ Peck) and the fall canker-worm[195] (_Alsophila pometaria_ Harris) are other caterpillars which often do much damage unless checked by destructive measures, of which the best are the arsenical sprays. The larvæ of a considerable number of other moths and butterflies are often found on plum foliage but seldom in such numbers as to require systematic destruction. The eye-spotted bud-moth[196] (_Tmetocera ocellana_ Schiffermuller) is a rather serious pest in plum nurseries where the larvæ eat into the young buds at the time they are opening, often destroying the shoots. Sometimes the larvæ are found destroying buds on old trees. The arsenical sprays are used to destroy this pest. The peach twig-moth (_Anarsia lineatella_ Zeller) is now and then found in plum twigs but is seldom classed as a plum pest.