INSECTS of... Conifer Foliage

Common Name:

PINE SAWFLIES

Slash pine sapling defoliated by larvae of the slash PINE SAWFLY.

Other:

1. Conifer sawfly
2. Webspinning sawfly

Species

1. Neodiprion spp.
2. Acatholyda sp.
See Table III: Common Species of pine-feeding sawflies

Common Hosts:

Loblolly pine Pinus taeda
Longleaf pine Pinus palustris
Pond pine Pinus serotina
Sand pine Pinus clausa
Shortleaf pine Pinus echinata
Slash pine Pinus elliottii
Spruce pine Pinus virginiana

Description

Adult -- female approximately 8-10 mm long; head with narrow antennae, body light to dark brown, robust and wasp-like, but waist is thick; wings light brown with prominent veins.
Pupa -- similar to adult; yellowish-white; conifer sawfly encased in a brown papery cocoon, webspinning sawfly naked.
Larva -- size variable, approximately 18-25 mm long when mature; see Table III for distinguishing characteristics to determine species.

Importance

Sawfly outbreaks are cyclical (approximately 8-10 year intervals) and can occur over a widespread area. Severe defoliation during late fall can result in reduced tree growth, lowered resistance to other pests (bark beetles) and death.

Biology and Habits

Fig. 6. General appearance of a sawfly larva. The characteristics commonly used to distinguish species are head coloration, background color of the body, and pattern of stripes and/or spots on the body. Identification of host tree species is also useful for accurate sawfly species identification.

Signs of Infestation

Loss of foliage; older foliage consumed before current foliage; branches appear tufted-like. Needles with straw-like appearance or small light-yellow patches (egg pockets) along the length of needles. Colonies of sawfly larvae on branches; larvae may number in the hundreds per colony. Thick layer of green to brown pellet-like frass (insect wastes) in leaf litter. Webbing attached to needles and shoots (webspinning sawfly only).

Control

Natural enemies and unfavorable weather usually keep webworm populations at low levels. Virus diseases and insect parasites are particularly useful in sawfly control. Promote tree vigor and health to aid in the recovery from defoliation. Use an approved insecticide.

BACK

Bulletin No. 196-A | Printed October, 1983 | Contact the Forest Health Section

Florida Department of Agriculture and Consumer Services