HOST PLANTS: Many aphid species feed on only one plant species, while others feed on hundreds of plant species. DAMAGE: Many species of aphids cause the greatest damage when temperatures are warm but not hot. Plants exhibiting aphid damage can have a variety of...
HOST PLANTS: Blue Colorado Spruce is the primary host. Norway Spruce is resistant. Other spruces and pines are infrequently attacked. DAMAGE: Symptoms of needlecast appear between early spring and early summer when needles infected the previous season turn purple or...
HOST: Crabapples and apple vary widely in their resistance to scab. Related (but different) species of the fungus that cause apple scab produce scab on hawthorn, mountain ash and pyracantha. DAMAGE: Apple scab describes the disease as it appears on the disfigured host...
