Garden Troubleshooting

Downy mildews, including Peronospora and Plasmopara spp., are pathogenic water molds (oomycetes) that primarily damage foliage. Hosts include cane berries, roses, various herbaceous ornamentals, and many fruit, grain, and vegetable crops. CategoryFungiSigns/SymptomsDowny mildew causes pale green to…

 Fire blight is a common and frequently destructive disease of pome fruit trees and related plants.  The disease can destroy limbs and even entire shrubs or trees. Caused by the bacterium Erwinia amylovora. Pear (Pyrus species) and quince (Cydonia) are extremely susceptible.  Apple, crabapple …

Fungus that only infects tomatoes. Like verticillium, causes leaf yellowing and discoloration of water-conducting tissues. Fungi spread in soil water, on equipment, transplants, or tubers. Once inside the root, the fungus grows until it reaches the water-conducting cells, inside which it spreads upward…

Late blight of potato was responsible for the Irish potato famine of the late 1840s. Late blight is caused by the oomycete Phytophthora infestans. Oomycetes are fungus-like organisms also called water molds, but they are not true fungi. CategoryFungiSigns/SymptomsLesions appear as small dark green water…

 Powdery mildew is a common disease on many types of plants and is prevalent in many areas of California. Infection occurs when fungus contacts a suitable host and environmental conditions are favorable. Infections spread as spores produced in these white patches move by wind and splashing rain to other…

Virus transmitted by aphids. After feeding on an infected plant, aphids are only able to transmit this virus for very short periods of time (minutes to a few hours). In general, spread of potyviruses in the field occurs when aphid activity is high and is often very rapid and localized. …

Prevalent household pest in households. Most common outdoor ants in California are Argentine ants. Body is constricted, giving appearance of a thin waist, which distinguishes it from termites. Adults, known as workers, are wingless. Pharaoh ants are found indoors. Carpenter ants damage wood structures…

 Small insects that suck fluids out of stems, leaves, and other tender plant parts. Soft pear-shaped bodies with long legs and antennae and may be green, yellow, brown, red, or black. A few species appear waxy or woolly due to the secretion of a waxy white or gray substance over their body surface…

Common vegetable garden pest that also attacks ripening stone fruit. Adult beetles are shiny with black heads, long antennae, and about one-quarter inch long. Striped or spotted depending on species. Larvae are whitish and slender with three pairs of short legs; the head and tip of the abdomen are darker…