southwestern pine tip moth, Rk. neomexicana (Dyar), which the parasite also attacks 
but in which it is unable to develop, increased very rapidly in the area about this 
time, and parasitism of R. bushnelli declined. This may have happened because the 
parasite deposited too many of its eggs in R. neomexicana. 
The subtropical pine tip moth, R. subtropica Miller, occurs throughout the 
range of slash pine in the South (998). Slash pine is the preferred host, but longleaf, 
loblolly, and Caribbean pines are also attacked. South Florida slash pine is fairly 
resistant. Heavy infestations have been recorded in Florida where typical slash pine 
has been planted south of its range, whereas naturally regenerated slash pine 
seedlings have rarely been infested. Serious losses of grafted slash pine scions in 
tree improvement programs have been incurred. 
Rhyacionia sonia Miller has been recorded in Ontario, Michigan, and Manitoba. 
Its host is sack pine. There is one generation per year and it overwinters as a pupa 
beneath trees. Superficially, the adult is similar to that of R. aktita Miller, a species 
occurring on the Coastal Plain from Maine to Texas (998). The hosts of R. aktita are 
pitch, loblolly, and slash pines. It overwinters as a pupa in infested tips. Both 
species have been mistaken for R. frustrana trom which they differ structurally in 
the adult stage. 
Extensive studies of Rhyacionia pheromones indicate the utility of such com- 
pounds for surveying for Rhyacionia and other purposes (99). 
The pitch twig moth, Petrova comstockiana (Fernald), 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 about 19 mm. 
In Ohio, eggs are deposited on twigs during May and June. The larvae bore into 
and downward in the twigs for distances from 8 to 10 cm, and pitch masses form 
over the entry holes (fig. 53). Winter is spent as a larva under the pitch mass. 
Development is resumed in May, and pupation occurs under the mass. There is one 
generation per year. Damaged twigs break off, leading to deformation of infested 
trees. The braconid Agathis pini (Muesebeck) has been a major factor in control 
(S59). A similar moth, P. taedana Miller, attacks loblolly pine throughout the South 
(S54). 
SAUER 
pSirasess 
ea 
EATEN 
F-519519 
Figure 53.—Larva of the pitch twig moth, Petrova 
comstockiana, in a red pine twig. Pitch mass covers 
the opening to the larval gallery. 
153 
