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Plant NameTypeDescription 
Boron deficiencyHollyDiseaseBoron deficiency in holly is characterized by the appearance of spots on the leaves. The spots initially are red to purple and irregularly shaped on the upper surface. They appear water-soaked on the lower leaf surface. Later, the spots enlarge and may assume a target-like pattern bordered by yellow. Premature leaf drop may also occur. Leaves of boron-deficient plants are often deformed and stunted. Other problems may cause similar leaf spot symptoms on holly.
Green algaeHollyDiseaseGreen algae grows on the surface only of leaves, twigs, and trunks. Wet, humid weather favors development of these microscopic, moisture-loving, primitive plants. The colonized holly is not harmed unless sufficient algal growth develops on the leaves and interferes with the photosynthetic process. Algal growth can cause plants to appear somewhat dirty or unhealthy. Typically, however, algae is only an aesthetic concern.
Phytophthora leaf & twig blightHollyDiseaseLeaf and twig blight of holly is caused by a different Phytophthora species than is associated with root rots. Symptoms first appear in the fall and winter during wet, cool weather. Leaves develop purple to black spots and may drop from the plant. Twigs develop cankers and die back. The disease begins on the lower portions of the plant and progresses upward through the winter. Disease development usually stops in the warm, dry weather of summer. Phytophthora leaf and twig blight is mainly a concern in nurseries and holly orchards.
Red leaf spottingHollyDiseaseRed leaf spotting of holly is a general category which includes physical or pesticide damage, nutritional deficiency, and disease symptoms. Damage from the holly's own spines can cause leaves to develop red or corky marks where the leaf was scratched or punctured. Also, boron deficiency causes spotting of leaves. English holly (Ilex aquifolium) may develop a disease called scab, which causes swollen, red to black, corky spots on the leaves. The spots usually are on the underside of the leaf, but may appear on the upper surface. The toxicity of copper in fungicidal sprays may cause holly leaves to develop purple spots or blotches on the lower (and sometimes upper) leaf surfaces. Finally, insect damage to the leaves may result in red spots.
Brown soft scaleHollyInsectBrown soft scales are yellowish to dark brown insects (adults are usually darker) up to approximately 1/8" in diameter. They are found mainly on the underside of leaves or on green twigs. Soft scales produce large amounts of honeydew, a sweet, sticky material which may attract ants or become covered with a growth of dark sooty mold. Heavy scale infestations can cause branches or whole plants to become wilted or yellowish or show other signs of stress. Brown soft scales are also common on camellia, dogwood, and daphne, as well as being serious pests of houseplants and greenhouse ornamentals.
Cottony camellia scaleHollyInsectThe cottony camellia scale is a flat brownish or yellowish insect about 1/8" in diameter. The scales overwinter on twigs or evergreen leaves. In the spring, the adult females lay cottony egg masses on the underside of leaves. Crawlers (young scales) feed on the underside of leaves. Cottony camellia scales produce large amounts of honeydew, a sweet, sticky material which may attract ants or become covered with a heavy growth of dark sooty mold. Foliage with scale infestations may turn yellowish and appear stressed. Eventually, the plant may become weakened. Cottony camellia scales also infest camellia, yew (Taxus spp.) and occasionally other ornamentals including hydrangea, English ivy, and maple.
Holly bud mothHollyInsectThe adult holly bud moth is a mottled brown and black insect with a wingspan of approximately 1/2". Overwintering eggs hatch in the spring. The larvae begin feeding on buds but soon move to leaves, which they roll and hold in place with webbing. The larvae are greenish-brown with dark heads and about 1/2" long. Another name for the holly bud moth is the blackheaded fireworm. It also feeds on cranberry, blueberry, apple and cherry.
Holly leafminerHollyInsectThe holly leafminer feeds on English (Ilex aquifolium), American (I. opaca) and Japanese (I. crenata) hollies, tiny green blisters on the lower leaf surface often indicate sites where the females deposited eggs. Characteristic damage by larvae includes the presence of yellow, brown, or reddish mines on the leaves. Initially the mines are fairly narrow and winding, but become large blotches as the larvae overwinters in the leaf. The upper and lower leaf surfaces remain after feeding, but are easily separated. Larvae are yellowish and about 1/16" long. The adult is a small black fly.
Lecanium scaleHollyInsectLecanium scales are shiny brown insects found on leaves and twigs. Adults are 1/8"-1/4" in diameter and roughly turtle-shaped. Crawlers (immature scales) are flatter. Scales produce large amounts of honeydew, a sweet, sticky material which may attract ants or become covered with a growth of dark sooty mold. Heavily infested plants may appear yellowish or wilted, or show other signs of stress. New leaves may be stunted. Lecanium scale is a common pest in the landscape, infesting many plants including dogwood, maple, rhododendron, willow, and fruit trees.
Orange tortrixHollyInsectThe larval stage of the orange tortrix is a leafrolling caterpillar. The larvae are tan to pale green with tan heads and about 1/2" long at maturity. The feeding caterpillars typically roll or twist individual leaves or clusters of leaves at shoot tips and tie them into loose nests with webbing. The larvae are very active when disturbed. The orange tortrix is a pest of many woody plants, including fruit trees and several common landscape plants such as holly, rose, euonymus, oak, and willow.