cone and seed insects -specialists in highly nutritious structures -life cycle closely tied to reproductive structure development

cone and seed insects -specialists in highly nutritious structures -life cycle closely tied to reproductive structure development

may impact natural regeneration importance of seed and cone insects seed production areas seed orchards nut production areas

importance of seed and cone insects great investment of resources in seed orchards genetic improvement work

examples of impacts 15-89% of white spruce cones destroyed by insects over 5 years (Werner 1964) 33% Douglas-fir seed and 59 % western larch seed destroyed by insects in Montana (Shearer 1984)

examples of impacts yields of southern pine seed reduced by 90% without insect control (Fatzinger 1980) red pine seed production area, 5 insects account for 34 to 83% of losses

pine seed development 15-20 months insects attack all stages conelets (1 st year) cones (2 nd year)

spruce, fir, and douglas-fir seed development completed within one year all stages attacked

major orders including seed and cone insects lepidoptera: coneworms and seedworms coleoptera: cone beetles and cone weevils hymenoptera: sawflies and seed chalcids

diptera: cone midges hemiptera: seed bugs homoptera: aphids and scale insects thysanoptera: thrips

cone crops and insect abundance cone crops fluctuate greatly strategies for survival extended diapause use of alterate structures wide host range

pine cone beetles - conophthrorus among most destructive cone and seed insects 11 species in NA 2-4 mm dark shiny beetles

Generalized pine cone beetle life cycle Adult beetles bore into conelets in spring Adult overwinters in cone, shoots, or conelets Beetles mate and lay eggs in cone; cone may drop or remain on tree Pupation and transformation to adult occurs inside cone Larvae feeds and develops inside cone

White pine cone beetle damage, notice entry hole at base of cone and damage along cone axis.

pine cone killed by cone beetle

ponderosa pine cone weevil, Conotrachelus neomexicanus adult is gray-brown in color 6 mm long prominent downcurved snout half as long as body body and legs covered with white and gray-brown scales

Ponderosa pine cone weevil, Conotrachelus neomexicanus, life cycle Adult emerges, feeds on shoots, and returns to ground for the winter Overwinter as adults in ground Emerge in spring and feed on shoots and flowers After mating, female oviposits at tip of scale Larvae exits cone and pupates in ground Larvae develops inside cone, destroying it

Leptoglossus occidentalis, western conifer seed bug widely distributed in western us wide host range adults 15-18 mm long, 4-6 wide reddish-brown to dark gray zig-zag line acroos back laterally expanded tibia on hind legs

Western conifer seed bug life cycle Emerges in spring and feeds on cones and flowers Overwinter in protected locations Complete development to adult and continue feeding Eggs laid in needles After hatching, nymphs feed on cones and seeds Nymphs go through 5 instars

western conifer seed bug stages and damage

coneworms, Dioryctria sp. widely distributed in NA most damaging lepidoptera in c & s feeds internally external signs

coneworms, Dioryctria sp. also shoots and bole wide host range adult moth 23-30 mm forewings with gray, orange, white marks hindwings white clear larvae active in summer various ow habits

Dioryctria auranticella life cycle in ponderosa pine Adults emerge, mate, lay eggs in late summer larvae feed internally and pupate inside the cones in late July Apparently, overwinter as early-instar larva Appear in cones in late spring-early summer

seed chalcids, Megastigmus spermotrophus adults is 3-4 mm long yellow body major mortality factor in Douglas-for orchards no external signs of damage exit hole in seed

Megastigmus spermotrophus life cycle in Douglas-fir Adults emerge in late spring Mature larvae overwinters inside seed and pupates in early spring Female oviposits through sales into seed Larvae develops through 5 instars consuming seed contents

some other insects: thrips

some other insects: seedworms

some other insects: spruce gall midge

control strategies for cone and seed insects use of aerial or ground-base insecticides use of systemic implants

control strategies for cone and seed insects prescribed fire (white pine cone beetle) pheromone-based strategies