Petrova (formerly Retinia) comstockiana

The native pitch twig moth is a clearwing moth species that will develop in the twigs of pine, particularly pitch pine, of the current year's growth. This difference sets them apart from other similar species in the same genus (Petrova) on similar hosts. For example, the pitch twig moth may be confused with the northern pitch twig moth (Petrova albicapitana) however that insect is known from lodgepole and jack pines. Details of the development of this insect were reported from studies completed in 1951 through 1953 in Ohio by Miller and Neiswander (1956), however this insect was described initially by Fernald in 1879 from specimens collected in pitch pine in Ithaca, NY by Professor J. Henry Comstock, to whom Charles H. Fernald dedicated the species. A single generation occurs per year, however historically there has been confusion as to whether or not two generations per year were possible. Two generations per year may occur in the southern portion of the insect's range, where it has not yet been studied. Eggs of this species are tiny, circular, and yellow when first laid by the adult female moth. Eggs hatch and caterpillars were present in Ohio by June. Early feeding by the caterpillars is completed at the needle bases for 1-2 weeks. Caterpillars molt at least once before then boring into the twigs and feeding, creating a nodule. After a month of feeding, the caterpillars move through the center of the twig and begin feeding on the pith. The feeding done by this insect causes ample resin (pitch) to leak from the initial feeding sites. Resin combined with frass form the characteristic nodule created by the activity of this insect. Nodules are typically found on the upper surfaces of the twigs. Caterpillars may work to expand these nodules using their mouthparts, moving resin, frass, and silk. Nodules formed on pitch pine are dark red-orange and those on Scotch pine are a lighter orange. During the winter, when larvae are inactive, weathering removes this coloration from the nodules. On average, these nodules are 7/8 of an inch long, but may vary from 1/2 to 1 and 1/4 inches long. At least 5 larval (caterpillar) instars may occur, however this information is not known for certain. Partially grown caterpillars overwinter with their heads positioned toward the lower end of the tunnel they create in the pith of the host plant twigs. In Ohio, by early April the caterpillars resume their activity in the spring. Once mature, the caterpillars create an exit tunnel, which enable them to pupate within their nodule, but emerge from an exit hole which causes the pupa to emerge from the nodule halfway at the time the adult moth is ready to emerge. In Ohio, pupation occurred by the end of April for a period of 4-5 weeks. Adult moths were present by May (Miller and Neiswander, 1956). Jones and Kimball (1943) found the flight period of adult moths in Nantucket and Marthas Vineyard, MA to be from approximately June 19 to July 22, at the time.