Southern Pineworm: Appearance, Territory, Damage and Life Cycle

Latin name: Dioryctria Amatella

Appearances: The wingspan is between 27 and 32 mm. The forewings are vividly patterned with several contrasting white patches and zig-zag cross bands and range in colour from dark grey to brown to nearly black. The hindwings range in colour from light grey to tan.

Host Plants: Dioryctria Amatella, popularly known as the pitch moth, is regularly one of the most destructive insect pests of pine seed orchard crops. This common bug also affects other sections of pine trees besides cones, which is less well-known. Caterpillars eat on and in buds, male and female flowers, shoots, branches, and stems of all ages and sizes, as well as first-year and second-year cones. The presence of Dioryctria Amatella infestations on forest and shade tree pines prompts concern about the damage it does on a regular basis.

Territory: The southern pinecone worm moth, Dioryctria Amatella, belongs to the Pyralidae family of moths. It can be found from Maryland to Florida and west into Texas in the south-eastern United States.

Damage Caused: Larval eating causes damage in cones that ranges from visible tunnels to completely excavated cavities, causing in partial to total seed loss in afflicted individuals. The intensity of applied cultural methods increased the abundance of Dioryctria amatella infestations in young, experimental slash pine plantations (e.g., fertilization, competition control, and irrigation).

Life Cycle and Habits: Depending on whether larval diapause occurs in the spring, early summer, or at all, the southern pine coneworm produces one to four generations per year in Florida. From early April through early November, the overlap of life stages among generations results in varied degrees of adult moth activity. Early instar larvae are found at the base of persistent cones, behind bud scales, and in fusiform galls on branches and sterns, where they overwinter. When larvae emerge in January, they may feed in overwintering sites or travel to feed on growing male and female flowers, as well as vegetative buds. Larvae frequently travel a second time after flower and bud feeding, infesting growing shoots or young second-year cones in early spring. Larvae may enter diapause, complete their development, or move back to immature second-year cones once in shoots.

Conelets affected with southern cone rust, as well as healthy second-year cones, are rapidly infested by the following generation of caterpillars in April and May. Before pupating, these larvae, as well as those of succeeding generations, may travel from infested to uninfested cones. From summer until fall, later generations continue to infest second-year cones.