Pine Sawflies
Introduction
There are over 100 species of sawflies in the U.S. whose larvae feed on the foliage of conifers; several occur in Tennessee including introduced pine sawfly (Diprion similis), redheaded pine sawfly (Neodiprion lecontei), and European pine sawfly (Neodiprion sertifer). Sawflies are not actually flies (Order Diptera), but rather they are a type of non-stinging wasp (Order Hymenoptera). They are called sawflies because they resemble flies and have a saw-like appendage that protrudes from their abdomen which is used to insert eggs into pine needles. Sawfly larvae are potentially serious defoliators of many pine species in Tennessee; heavy defoliation can lead to growth loss or mortality. Outbreaks of this pest generally do not warrant control measures, but sawfly activity should be closely monitored to prevent serious damage. This pest is most common in young plantings, but trees of all ages may be attacked.
Introduction
There are over 100 species of sawflies in the U.S. whose larvae feed on the foliage of conifers; several occur in Tennessee including introduced pine sawfly (Diprion similis), redheaded pine sawfly (Neodiprion lecontei), and European pine sawfly (Neodiprion sertifer). Sawflies are not actually flies (Order Diptera), but rather they are a type of non-stinging wasp (Order Hymenoptera). They are called sawflies because they resemble flies and have a saw-like appendage that protrudes from their abdomen which is used to insert eggs into pine needles. Sawfly larvae are potentially serious defoliators of many pine species in Tennessee; heavy defoliation can lead to growth loss or mortality. Outbreaks of this pest generally do not warrant control measures, but sawfly activity should be closely monitored to prevent serious damage. This pest is most common in young plantings, but trees of all ages may be attacked.
Management
Usually not required. Severe infestations usually subside naturally after 1 or 2 years, but populations of this pest should be monitored to avoid serious damage. Rapid population declines are usually due to predation by rodents, birds, and a viral disease that spreads rapidly through large populations. Chemical control options are available but are only effective against early instars. Because generations overlap considerably, larvae at all stages of development are usually present making successful treatment difficult. Often, by the time severe defoliation is detected it is too late to apply insecticides. The best option is to wait until the following year, monitor the new population, and treat early in the growing season if necessary.
