common name: pine sawflies
scientific name: Neodiprion spp. (Insecta: Hymenoptera: Diprionidae)
Pine sawfly larvae, Neodiprion spp., are the most common defoliating insects of pine trees,
Pinus spp., in Florida. Sawfly infestations can cause growth loss and mortality, especially when
followed by secondary attack by bark and wood-boring beetles (Coleoptera: Buprestidae,
Cerambycidae, Scolytidae,). Trees of all ages are susceptible to sawfly defoliation (Barnard and
Dixon 1983, Coppel and Benjamin 1965).
blackheaded pine sawfly larvae
Neodiprion spp. are indigenous to Florida. Host tree specificity and location will bear on sawfly
distribution statewide.
Six species are covered here so there is some variation in appearance. However, an adult female
has a length of 8 to 10 mm, with narrow antennae on the head and a stout and thick-waisted body.
This is unlike most Hymenopteran insects which have the thinner, wasp-like waist. The
background color varies from light to dark brown, with yellow-red-white markings common.
The two pairs of wings are clear to light brown with prominent veins.
Adult female Neodiprion sp.
(Adapted from Atwood 1961)
redheaded pine sawfly female
The adult male has a length of 5 to 7 mm. The male has broad, feathery antennae on the head with
a slender, thick-waisted body. It generally has brown to black color wings, similar to the female.
adult male slash pine sawfly
blackheaded pine sawfly adults
Egg are small (0.5 mm wide x 1.8 mm long), green-yellow-white color, and ovoid.
redheaded pine sawfly eggs
The length of the mature larva is 18 to 25 mm with variable coloration (see Table 1).
Virginia pine sawfly larva.
Georgia Forestry Commission
Slash pine sawfly larva.
Georgia Forestry Commission
redheaded pine sawfly larvae
blackheaded pine sawfly larvae
The pupa length is similar to that of the adult. The cocoon is light brown to dark reddish-brown,
papery, and 3.5 to 6.0 mm wide x 7.1 to 10.0 mm long (Coppel and Benjamin 1965, Thatcher 1971,
Wilkinson 1965).
redheaded pine sawfly cocoon
redheaded pine sawfly adult emerging
blackheaded pine sawfly cocoons
Mature sawfly larvae spin cocoons in the duff or pine litter, mineral soil, or under bark scales.
Adult sawflies emerge by removing a cap at one end of cocoon. After mating, female sawflies
lay eggs in slits sawed in pine needles. Small larvae feed on outer needle tissues; larger larvae
consume entire needles. Most species prefer older foliage, but all foliage is susceptible at end of
growing season. Larval colonies may migrate from one tree to another, especially upon
complete defoliation of the host tree or high feeding competition. The number of sawfly
generations (one to four) varies from year to year and according to species. Larvae may
diapause (a survival behavior for adverse conditions) for more than one year (Coppel and
Benjamin 1965, Wilkinson 1980).
blackheaded pine sawfly cocoons
female oviposition
All southern pines, Pinus spp., are susceptible to sawfly infestation.
blackheaded pine sawfly damage
redheaded pine sawfly damage
Virginia pine sawfly damage
Virginia pine sawfly damage
Early damage is evidenced by reddish-brown strawlike remains of needles that are incompletely
consumed by young larvae; older larvae leave only short stubs. Partially defoliated branches
often have a "bottle brush" appearance. Sawfly colonies may consist of a few to over a hundred
individuals. Upon disturbance, larvae may drop from branches or assume a U-bend by raising
head and abdomen. An oral exudate, which can paralyze insectan parasites and repel predators,
often accompanies such displays (Barnard and Dixon 1983, Coppel and Benjamin 1965).
TABLE 1. Description of pine sawfly larvae, Neodiprion spp., in Florida.
| Common Name |
Species |
Description |
Host Trees1 |
slash pine sawfly |
Neodiprion merkeli
Ross |
Two-tone head (red above,
black below); yellow-green
body with two faint black
stripes and a large black spot
on hind end of each side |
slash pine |
redheaded pine
sawfly |
Neodiprion lecontei
Rohwer |
Red head; whitish or
yellowish green body with three
rows of irregular black spots;
large black spot on hind end
of each side |
longleaf pine,
slash pine |
blackheaded pine
sawfly |
Neodiprion
excitans Rohwer |
Shiny black head; olive-green
body with two black stripes and
row of black spots; large
black spot on hind end of
each side |
loblolly pine,
pond pine,
sand pine,
spruce pine |
Virginia pine
sawfly |
Neodiprion pratti
pratti (Dyar) |
Black head; pale green body
with two black stripes and a row
of black spots on each side of
the body |
loblolly pine,
Choctawhatchee
sand pine
|
| a pine sawfly |
Neodiprion
virginianus Ross |
Black head; row of distinct,
nearly square black spots on
each side of the body |
Ocala sand pine |
| spruce pine |
Neodiprion warreni
Ross |
Black head; two dark stripes on
each side of the body |
spruce pine |
| Abbot's sawfly |
Neodiprion abbotii
(Leach) |
Brown-black head with a
white spot on the front;
yellow to pale green body
with two dark green stripes on
each side of the body |
loblolly pine,
longleaf pine,
shortleaf pine,
slash pine
|
1 Choctawhatchee sand pine = Pinus clausa var. immuginata D.B.Ward; loblolly pine = Pinus taeda L.; longleaf pine = Pinus palustris Mill.; Ocala sand pine = Pinus clausa var. clausa (Chapm.) Vasey; pond pine = Pinus serotina Michx.; shortleaf pine = Pinus echinata Mill.; slash pine = Pinus elliottii Engelm.; spruce pine = Pinus glabra Walt.
frass under tree
Suppression of sawfly populations by insecticides is usually successful. However, consideration
should be given to conserving natural enemies (small mammals, birds, insects) through minimal
insecticide use and preservation of cypress-hardwood pond stands around pine plantations. The
appearance of numerous dead larvae hanging from needles, i.e., virus-infected, usually signals
the collapse of a sawfly outbreak. Sawfly outbreaks are cyclical - an eight to 10 year interval is
common. A fully stocked stand and promotion of early crown closure minimizes risk of sawfly
damage in pine plantations (Wilkinson 1980).
Insect
Management Guide for forest and shade trees
-
Atwood CE. 1961. Present status of the sawfly family Diprionidae (Hymenoptera) in Ontario.
Proceedings of the Entomological Society of Ontario 91: 205-215.
- Barnard EL, Dixon WN. 1983. Insects and diseases; important problems of Florida's forest and
shade tree resources. Florida Department of Agriculture and Consumer Services, Division of
Forestry Bulletin No. 196A. 123 p.
- Coppel HC, Benjamin DM. 1965. Bionomics of the Nearctic pine-feeding diprionids. Annual
Review of Entomology 10: 69-96.
- Thatcher RC. 1971. Spine sawfly, Neodiprion excitans Roh. U.S. Department of Agriculture.
Forest Servive Pest Leaflet 105. 4 p.
- Wilkinson RC. 1965. Neodiprion merkeli from south Florida. Florida Entomologist 48: 27l.
- Wilkinson RC. 1980. Pine sawflies in Florida. In Forest pest management 12th spring
symposium for the Florida section of the Society of American Foresters, 3-4 June 1980.
University of Florida, Institute of Food and Agricultural Sciences Resources Report 7: 53-55.
- Wilson LF. 1970. The red-headed pine sawfly. U.S. Department of Agriculture Forest Service
Forest Pest Leaflet 14. 6 p.
Author: Wayne N. Dixon, Florida Department
of Agriculture and Consumer Services, Division of Plant Industry.
Originally published as DPI Entomology Circular 258.
Photographs: www.forestryimages.org, University of Florida, and FDACS-Division of Plant
Industry
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-317
Publication Date: January 2004
Copyright 2004 University of Florida
Featured Creatures
Department of Entomology and Nematology
Division of Plant Industry
Electtronic Data Information Source