Redheaded Pine Sawfly and Spotted Loblolly Pine Sawfly
These native species are two of the most important defoliators of pines in Maryland. Late-spring outbreaks of spotted loblolly pine sawflies, Neodiprion taedae taedae, often completely remove old needles before new shoots develop. Since new needles are left untouched, mortality rarely occurs, but tree vigor and growth may be reduced.
Spotted loblolly pine sawflies are a good example of forest pests that play minor roles in Maryland's forests. While populations of these sawflies occasionally build up to outbreak proportions, they have not caused serious problems in Maryland in the last ten years. In 1984 and 1985, about 145,000 acres of loblolly pine trees were defoliated. Little, if any mortality occurred since sawflies feed on older needles leaving new ones intact. While defoliations are unsightly and the caterpillars are a nuisance to people, these problems are temporary. Sawflies rarely cause enough damage to kill trees and cause few long term losses in forest benefits.
The redheaded pine sawfly, Neodiprion lecontei, usually attacks trees less than 15 feet tall. Pines planted in old fields appear most susceptible. Redheaded pine sawflies may have two or three generations each year. Mortality may occur after repeated defoliations, especially along forest edges where trees are under stress.