At least 60 species of parasites of the Nantucket pine tip moth 
have been recorded (798), but they are rarely abundant enough 
to provide satisfactory control. Low winter temperatures in the 
northern parts of the infested region provide some degree of 
control by killing overwintering pupae. Damage can also be re- 
duced by limiting the planting of susceptible pines to sites to 
which they are well adapted. Close spacing and planting under 
an overstory may also be helpful. 
Rhyacionia frustrana bushnelli (Busck), the western pine tip 
moth, occurs from the Dakotas and Nebraska south to New Mex- 
ico. Its preferred hosts are ponderosa, red, jack, and Scotch pines. 
Infestations have been particularly severe in pine plantations in 
Nebraska (308). The adult is indistinguishable from those of the 
Nantucket pine tip moth, although it tends to be larger. Heinrich 
(335) suggested that it and the true R. f. frustrana are one and 
the same, but Miller (528) believes that bushnelli may be a dis- 
tinct species because of its overwintering habit and size. There is 
one generation per year in the Dakotas and two per year in 
Nebraska. 
In 1925, Campoplex frustranae Cush., a common parasite of the 
Nantucket pine tip moth in the East, was liberated in infested 
plantations in the Nebraska National Forest. It became estab- 
lished immediately and increased rapidly. By 1930, parasitism 
at the original liberation point had reached 80%. Unfortunately, 
the related tip moth, R. frustrana neomexicana, which the para- 
site also attacks but in which it is unable to develop, increased 
very rapidly in the area about this time, and parasitism of R. f. 
bushnellt declined. This may have happened because the parasite 
deposited too many of its eggs on R. f. neomexicana. 
Rhyacionia subtropica Miller, a newly-described species (524), 
occurs throughout the range of slash pine in the South. Typical 
slash pine, Pinus elliott var. elliotti, is the preferred host, but 
longleaf, loblolly, and tropical pine are also attacked. South Flor- 
ida slash pine, P. elliottw var. densa, is fairly resistant. Heavy in- 
infestations have been recorded in slash pine plantations on poor 
sites in Florida; whereas naturally regenerated slash pine seed- 
lings have rarely been infested. Serious losses of grafted slash 
pine scions in tree improvement programs have been incurred. 
Rhyacionia sonia Miller, a newly-described species (528), has 
been recorded from Maine west to southern Manitoba and from 
South Carolina. Its hosts are jack and pitch pines in the North, 
and slash and loblolly pines in the South. Superficially, the adult 
is indistinguishable from those of R. f. frustrana and R. f. bush- 
nellt. Winter is spent in the pupal stage and there is one genera- 
tion per year. 
The pitch twig moth, Petrova comstockiana (Fern.), occurs from 
Maine to North Carolina and west into the Central States. Its 
hosts include the hard pines, but pitch pine is preferred in the 
Midwest. The adult is reddish-brown with gray mottlings and has 
a wingspread of 14 to 20 mm. 
In Ohio, eggs are deposited on twigs during May and June. The 
larvae bore into and downward in the twigs for distances of 3 or 
4 inches, and pitch masses form over the entry holes (fig. 144). 
Winter is spent as a larva under the pitch mass. Development is 
365 
