NEW YORK EXPERIMENT STATION BULLETIN 371 



THE NEW YORK TLUM LECAXIUM. 

 Lecanium ceraxi/ex *Fitch (?). 



The 8uddon apiioiuance of this insect tliree years ago in overwhelming 

 nnmbei's in some of tlie large plnm orchards of western Kew York, is 

 doiiblless flesh in the memory of orcliardisLs and nurserymen throughout 

 the state. Very little is heard of this scale now, however, owing to the 

 fact that it disappeared almost as suddenly as it came. But it may still 

 be seen occasionally in most plum orchards, and during the past season 

 we found il scattered in several nurseries, hence it may yet be considered 

 a pest which should be carefully watched with a view to preventing other 

 serious outbreaks. 



History. — Previous to 1893 but little Avas known of this insect in this 

 state although it seems to be the prevailing opinion among prominent 

 fruit growers that the insect has been in the plum orchards of Western 

 New' York for twenty years or more but not in sufficient numbers to cause 

 special comment. During the seasons of 181).') and 1894 the insect did 

 great damage to western New York plum orchards, but in the spring of 

 1895, comparatively few of the scales could be found, most of them having 

 succumbed to the attacks of parasites, predaceous insects and climatic 

 changes. 



Present distribution. — Accurate data as to the present distribution 

 of this insect is wanting. This, or a very similar species, however, is 

 known in the south, and a species which is probably identical is reported 

 from England. Judging from our observations during the past season, 

 the scale is at present scattered through many of the larger plum 

 orchards in western New York and may be occasionally seen in the nur- 

 series, but in only a few cases have we found it in suthcient numbers to 

 do serious injury. We have observed the s])ecies in the following coun- 

 ties: Niagara, Orleans, Genesee, Monroe, Ontario, Seneca, Cayuga, Onon- 

 daga, Richmond and Queens. 



Food plants. — As its name indicates, this species is especially injurious 

 to the plum. It has also been reported upon apple, pear, maple, Cissus, 

 cherry and peach. In addition to these food plants the Avriter has found 

 a \er\ closely allied, if not identical, species upon quince, apricot, culti- 

 vated blackberry, cultivated grape, honey locust, black ash, and iron 

 wood [Ostri/ia.] 



Descriptions and life history. — A detailed account of this insect is 

 given in the Fourteenth Annual Report of this Station, pages 574-593. 

 As comparatively few of the reports are left for distribution, however, 

 it may be well to repeat the life histor}- of the insect substantially as 

 given therein. 



The general appearance of the insect is shown at Plate I, fig. 5. At a 

 the mature scales are shown enlarged, and at h the mature and young 

 hibernating scales, natural size. Unlike the two preceding species, this 

 scale passes the w'inter in the larval state. After the first few warm 

 days of spring, the young scales begin to move about, but soon find a 

 suitable place to settle dow'n to again suck the sap of their host plant. 

 They soon begin to grow with astonishing rapidity. Previous to this 

 time the male and female scales are very much alike, but as the season 



* Identified by Mr. Th. Pergande. 



