Pests & Diseases

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Downed tree with exposed roots in front of residence.
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Storm Damage in Landscapes

January 27, 2021
Strong winds from the latest winter storm have downed trees and branches throughout Northern California and may have also damaged plants in your garden and landscape. Further damage from wind or hail can be reduced with proper cultural care.
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Figure 1. A healthy backyard lawn. (Credit: C Reynolds)
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Lawn Problems: Diseases Are Not Always To Blame

July 16, 2020
By Janet S Hartin
Your customers want their lawns to be beautiful and functional (Figure 1) but dead patches or other problems sometimes occur. Figuring out the cause of turfgrass damage can be a challenge since many plant pathogens affect grasses as well as numerous abiotic (non-living) disorders.
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Tanbark oaks killed by Phytophthora ramorum. (Credit: P Svihra)
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Invasive Spotlight: Sudden Oak Death

June 7, 2020
Sudden oak death is a disease of oak trees that is caused by an invasive plant pathogen Phytophthora ramorum. The disease has been found infecting trees in coastal California counties from Monterey to Humboldt and can be spread by moving infested soil and plant material. In California, P.
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Black leaf spots caused by Chinese elm anthracnose.<br>(Credit: Jack Kelly Clark)
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Anthracnose Pest Note Updated

May 14, 2020
Anthracnose is a group of fungal diseases that infect many trees and shrubs, causing dark lesions on leaves and cankers on twigs and stems. In some areas of California, vegetables and turfgrass can also be infected with anthracnose. Symptoms of anthracnose vary by plant host and weather conditions.
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Powdery mildew damage on tomato leaves. (Credit: Jack Kelly Clark)
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April Gardening Tips: Powdery Mildew

April 23, 2020
As you practice social distancing during COVID-19, you may find yourself spending more time in the garden. As we move into nice weather, we are sharing a few gardening tips for pest management. Check for signs of powdery mildew on fruit trees, landscape ornamentals, and vegetables.
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Close up of top and bottom of rose leaves infected with rose rust.
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Are Your Roses Diseased?

March 17, 2020
Roses in the garden can be infected with a variety of bacteria, fungi, and viruses, leading to diseases like powdery mildew and rust. Roses may also be damaged by nutrient deficiencies and other environmental problems.
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A conk, the fruiting body of the fungus <i>Phellinus ignarius</i> on black walnut. (Credit: AJ Downer, UCCE Ventura County)
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Wood Decay Fungi in Landscape Trees

August 23, 2019
Landscape trees provide welcome shade, fruit, homes for wildlife, and even a place for kids to climb. But if the wood is damaged, disease-causing fungi can infect the tree. A number of fungal diseases decay wood in both tree branches and trunks, weakening and sometimes killing the tree.
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