34 THE PLUM CURCULIO. 
apricots are very uncertain croppers throughout the range of distri- 
bution of the insect on account of early blooming and consequent 
injury by frost. During fruiting years, however, in the absence of 
treatment, practically none of the fruit of these varieties escapes 
puncturing. During June, 1910, one of the writers examined several 
hundred apricots from trees in a neglected home orchard near Blue- 
mont, Va., without finding a single specimen free from infestation. 
As a group, plums constitute the favorite food of the curculio, 
and the various species of wild plums were without doubt the original 
native food of this species, and are freely used at the present day. 
The early literature of the-curculio abounds with references to its 
especial injury to cultivated plums, and growers of this fruit have 
complained bitterly of its ravages. With the extension of culture 
of other fruits, as peaches, apples, cherries, etc., its injuries to these 
fruits have likewise become more and more important. However, 
until in comparatively recent years the curculio was regarded as 
preeminently an enemy of plums. (See Pls. If and III, showing 
curculio injury to plums.) 
Cultivated varieties of plums appear to show variation as to sus- 
ceptibility to attack. There are frequent references in literature to 
the subject, but adequate data for conclusions are wanting. In an 
extended article Mr. D. B. Wier (Bulletin 14, old series, Division of 
Entomology, p. 39, 1887) presents under the caption ‘‘The native 
plums: How to fruit them—they are practically curculio proof,” 
results of observations which led him to believe that native plums 
are especially sought for by the curculio for oviposition purposes. 
Thus— 
The first and most important is that of evidence showing that this insect seeks 
native plums in preference to all other fruits in which to deposit her eggs. This isa 
queer fact in biology which naturalists will be inclined to dispute, namely, that an 
insect should seek and use seemingly by preference a fruit in which to lay her eggs 
wherein but very few of them will hatch and in which but one of such larvee as do 
hatch can be nourished on its substance to maturity. 
Further on he states: 
I found that for every egg that hatched, and the larve had fed noticeably, that there 
were from 1,500 to 1,900 ovipositing marks of the curculio and that only one living 
curculio maggot was found in 3,100 to 2,500 plums examined, and in which her eggs 
had been laid. These percentages are from the June observations of these two years 
and coincide with previous observations. 
Mr. Wier also observes: 
The reason why the plum curculio does seek the native plums to oviposit in seems 
to be because of their very early and fragrant bloom. 
His observations that native plums are much sought for as places 
for egg laying and that the larve are not able to develop therein, led 
