OBJECTIVES OF INSECT DEFOLIATORS At the end of this section students should be able to: 1) Know the difference among polyphagous, oligophagous and monophagous defoliators. 2) Know the principles of detection, evaluation and management of defoliators.
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Fall Webworm – Hyphantria cunea
Leaf chewers – eat entire leaf and include the
Pine sawflies, Gypsy moths, Spruce bud worm
Leaf skeletonizers – eat soft parts or the
epidermal layers – not the veins.
Leaf miners – bore inside leaves, between
The upper and lower epidermis. Includes, the
Pine needle miners and the Aspen leaf miner
Secondary damage occurs when
defoliated trees are weakened and
subject to attack by secondary pests
such as wood borers, bark beetles, or
soil fungi – Armillaria spp
Lepidoptera: Many insect species
Includes Pine Butterfly, spruce budworm
Gypsy moth, catalpa worms
Oak slug sawfly
Coleoptera: Cottonwood Leaf beetle, June beetles,
Elm leaf beetle, & the Locust leaf miner.
Polyphagous - Many hosts, e.g.
Oligophagous – Few Hosts, e.g.
Monophagous – one hosts, e.g.
Spruce Budworm - Choristoneura fumiferana
egg mass on needle
Spruce budworm 3rd Instar in bud
Instars 4-6 feed on new foliage first and move to older foliage if necessary.
Populations are cyclic with peaks roughly every 8-10 yr. Major outbreaks every 60 years or so that corresponds with maturation of Balsam fir stand.
Management Considerations: Major outbreaks every 60 years or so that corresponds with maturation of Balsam fir stand.
Budworm Treated area to left of road Major outbreaks every 60 years or so that corresponds with maturation of Balsam fir stand.
End of Spruce Major outbreaks every 60 years or so that corresponds with maturation of Balsam fir stand.