Pine Coneworms (Dioryctria spp.)

Damage consists of larval tunnels or partly to totally excavated areas within the infested cones. Some
coneworms also feed in buds, shoots, flowers, and conelets. Six coneworm species are known to damage southern pines.

Southern pine coneworm, Dioryctria amatelle (Hulst) (7, 8, 20, 21, 24, 27, 29, 33, 40, 42, 43, 52, 53)⁵

BIOLOGY. - The southern pine coneworm has several generations per year with much overlapping of life stages. Male and female pine flowers, galls caused by fusiform rust (Cronartium fusiforme Hedg. & Hunt ex. Cumm.), injured tree stems, and cones may be infested. On slash and longleaf pines, early-season infestations tend to occur in flowers and shoots, in cones infected by southern cone rust (Cronartium strobilinum (Arth.) Hedg. & Hahn), and in fusiform rust galls. These larvae, except in gall infestations, often move on to complete development in cones. Fusiform rust galls sustain larvae through pupation. Second and subsequent generations of larvae develop primarily in cones. Early-season infestations of loblolly pine seem to be in fusiform rust galls, but succeeding generations infest the cones of loblolly and associated pines. Pupation occurs within the infested material. Larvae, usually first instars, overwinter.

Adult (2X)

INSECT IDENTIFICATION. - Mature larvae of the southern pine coneworm are somewhat variable in color, but tend toward dark purplish-brown above and nearly white beneath, with greenish tints especially in prepupal larvae. Dark elevated areas bearing setae and black beadlike patterns of small depressions are obvious on abdominal segments. Adults are dark brown, often appearing nearly black, with contrasting distinct white markings.

DAMAGE IDENTIFICATION. - A mixture of resin and frass is usually present on the surface of infested material, but resin may be scant or absent from maturing cones.

IMPORTANCE. -This coneworm is prevalent throughout the Southeast and is consistently
one of the most serious pests of pine cones.

Larva (2 1/2X)

Damage to loblolly pine cone. (1/2X)

⁵ Dioryctria taedae Schaber & Wood, a similar species reported from loblolly pine in Maryland, is reported to occur sparingly in the Southeast. It differs from D. amatella in having grayish, much less contrasting crosslines on the forewings. It has been confused with D. yatesi Mutuura & Munroe, which has similar wing coloration.