Oak Wilt

Oak Wilt is a disease caused by the fungus Bretiziella fagacearum that is specific to oaks (Quercus spp.). The fungus is spread through root grafts between neighboring trees and by insects. Red Oaks are particularly susceptible to oak wilt. The infection causes leaf discoloration, defoliation and death in a very short period of time (from […]

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Sudden Oak Death

Sudden oak death (SOD) is the common name for a fatal tree disease caused by Phytophthora ramorum, a species of oomycetes that are similar to fungi.  SOD is one of 59 species of Phytophthora, all of which cause disease in plants.  Many Phytophthora species attack roots in poorly drained or anaerobic soils.  The primary hosts […]

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Whitefly

Whiteflies are tiny, pure white, moth-like sucking insects that prefer to feed and lay eggs on the undersides of leaves. Several species are known to infest trees, including ash whitefly, citrus whitefly, crown whitefly and rugose spiraling whitefly. All produces “honeydew,” a sugary substance that drops and coats the house, car, or patio and make […]

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Bronze Birch Borer

The Bronze Birch Borer is a wood boring beetle, common across the northern half of the United States, which attacks all birch species. The adult is a copper/bronze colored slender beetle. The larvae, which does the damage, are unseen, feeding on the vascular tissue under the bark. The Bronze Birch Borer typically attacks trees which […]

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Oak Worms

There are several caterpillars that feed on oaks including the California oak worm and tussock moth. Each of these caterpillars feed on oak leaves. Oak worms are smooth, small, yellow-green caterpillars with brown heads and dark stripes down their sides. They can range from 1/10 to 1 inch in length throughout their development. Tussock moth […]

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Erythrina Gall Wasp

The Erythrina Gall Wasp is an exotic pest of the Wiliwili tree.  Common tree names include tigers claw, Indian coral tree and Wiliwili-haole.  It was first discovered in Hawaii in 2005.  Populations of Wili-Wili or Erythrina occur in Hawaii, California and Florida.  EGW completes its life cycle in as little as 21 days.  It is […]

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Winter Moth

Winter Moth causes severe defoliation of hardwood trees.  Winter Moth is appropriately named, as adult moths are generally active from November through January.  The larvae begin feeding early on developing leaves; severe infestations will cause noticeable tree defoliation.  In June, they drop to the ground to pupate in the soil until the fall.  Canadian research […]

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Goldspotted Oak Borer

The Goldspotted Oak Borer is a flat-headed borer that was originally found around the San Diego, California area. GSOB are currently known to attack three species of oak: coastal live, canyon live, and California black. Adult GSOB are usually 10mm in length and have bullet-shaped black bodies with gold spots on their sides. Oaks with […]

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Thrips

Thrips are slender, tiny insects that often have fringed wings and are generally 1 mm or less in size. Nymphs are elongate, lack wings and range in color from off-white or yellow to brown or black. Most thrips feed by sucking out cell contents of leaves or flowers, but some can cause leaf distortions or […]

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Aphids

Aphids are soft, pear-shaped insects that have long legs and antennae with tube-like structures called “cornicles” that protrude out of the hind end of the body. This family of insects contains most plant virus vectors (around 200 known) such as the green peach aphid. They can appear in a range of colors including green, yellow, […]

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