Monterey pine bud moth—Exoteleia burkei
Larvae of this moth (family Gelechiidae) tunnel inside the buds and shoot tips of various pines. It is primarily a pest of Monterey pine in coastal areas of Central and Southern California.
Identification
The damage, larvae, and pupae of Monterey pine bud moth closely resemble those of Monterey pine tip moth. Monterey pine can be infested with both species at the same time. A way to distinguish the species is to rear larvae or pupae to adults, such as by placing infested shoots in a ventilated container until adults emerge. Freeze the adults for several minutes to kill them. Allow them to thaw and examining the wing markings, which differ by species.
The adult of Monterey pine bud moth is a mostly reddish brown moth with black blotches and three, transverse, white bands on each front wing. The antennae are distinctly and alternately ringed with dark brown and white. The hind wings are uniformly covered with brown scales and have a wide fringe of hairs on the rear edge.
Larvae of Monterey pine bud moth are yellowish brown with a black head. They grow up to 1/4 inch long and are found in mined shoots and (when larvae are young) inside buds and needles. The brownish pupa is slightly shorter than the mature larva.
Life cycle
The adults are generally present from late April to June in Southern California and somewhat later in Central California. Single eggs are laid at the base of buds that will grow into shoots during the next growing season. The newly hatched larvae tunnel into buds and a modest amount of tunneling in shoots is done by young larvae during the current year. They overwinter as fourth-instars (old larvae).
During spring, the overwintered larvae resume feeding. Their tunneling damage becomes more extensive and external symptoms become more apparent. As spring warms, the tunneled shoots begin to discolor, wilt, and die.
Pupation usually takes place in the tunnel of the dried shoot, most often near a small hole. The pupal stage lasts 2 to 3 weeks. The adults then emerge, mate, and females lay eggs. There is only 1 generation per year.
Damage
Larvae of Monterey pine bud moth chew and feed on the buds, needles, and shoot tips of Monterey pine and other Pinus species. Their tunnels generally extend only 1 or 2 inches within terminals. Infested buds and shoot tips are killed and regrowth of the terminal is commonly crooked. Note that pine tip moths cause very similar damage.
Larvae of the Monterey pine bud moth make small mines in the center of the new buds and developing tips, causing them to wither, die, and become brown and dry. When the moth is abundant, most of a pine's shoot tips can be killed and the aesthetic value of the tree is decreased.
Tips injured by the bud moth continue to grow for 6 or 7 inches before dying. In contrast, pine tip moth larva chew away most of the inside of the developing tip, causing the growth to stop abruptly and the tip to quickly die.
Solutions
Damage is very localized and unlikely to threaten tree survival. Where feasible prune out and dispose of affected tips if their appearance is unacceptable.
Insecticide application generally is not warranted unless trees are of especially high aesthetic value, such as in Christmas tree farms. Where tip damage has been intolerable, apply a systemic insecticide (e.g., imidacloprid) to kill young larvae. To avoid drift from spraying and to avoid trunk injury from injecting insecticide the preferred application method is to drench imidacloprid onto soil around the base of the trunk.
Alternatively, spray foliage with a broad-spectrum, residual pyrethroid insecticide (e.g., permethrin or other insecticide ending in "thrin") soon after moths are observed flying in spring or early summer. Note that pyrethroids effective for this pest are available only to professional pesticide applicators and a professional with access to effective products must be hired to make the application. For how to get the services you want, consult Pest Notes: Hiring a Pest Control Company. Be aware that application of a pyrethroid or certain other insecticides can cause spider mite outbreaks and wash off into storm drains and pollute surface waters at concentrations toxic to some aquatic life.
For more information on this pest see Insects Affecting Ornamental Conifers in Southern California.
Adapted from the publication above and Pests of Landscape Trees and Shrubs: An Integrated Pest Management Guide, University of California Statewide Integrated Pest Management Program (UC IPM). |
