Many areas in California have experienced a hot and dusty summer, perfect conditions that favor spider mites! These tiny arachnids are plant pests whose numbers can get very high during the warm months of June through September.
Spider mites damage plants by sucking cell contents from leaves. If you see plant leaves with light dots on them (stippling) that turn yellowish or reddish and drop off, and/or large amounts of fine webbing on leaves, twigs, and fruit, your plants might have spider mites.
Spider mites look like tiny, moving dots that will move around rapidly when disturbed. To correctly identify these pests, use a 10x hands lens to view...
Squirrels commonly cause damage around homes and gardens when they dig holes, feed on fruits and nuts, gnaw on cables, or chew their way into buildings.
The squirrels in your landscape may be tree squirrels or ground squirrels. If you aren't sure which kind they are, visit the UC IPM web site to read about Tree Squirrels and Ground Squirrels.
If you know your arboreal visitors are tree squirrels, you can read more about them and their management in the newly revised UC IPM Pest Note: Tree...
If you see large black or golden-brown bees flying in your garden or landscape, don't be alarmed! These insects are most likely carpenter bees, and although their large size and loud buzzing can be intimidating, they are mostly harmless. Males can't sting and females rarely do, and both are considered beneficial because they are pollinators.
However, sometimes carpenter bees bore into lumber or trees to make nests and may damage structural wood or leave unsightly holes and stains. Multiple bees may use a common entry hole, tunneling several feet into wood to create chambers for their offspring.
The best way to manage carpenter bees boring into wood is through prevention. Use hardwoods in structures where possible...
Spring is a good time to begin monitoring for any lawn insect pests. Pest examples include various root, crown and leaf-feeding caterpillars, grubs like masked chafers, billbugs and chinch bugs.
Although insects can be serious pests of lawns, lawn damage is more frequently due to lack of proper cultural care and/or improper grass species selection for your area. An unhealthy lawn is more easily attacked by insects, weeds and diseases.
Insects are sometimes are blamed for lawn damage when the culprit may actually be disease-causing pathogens, dog urine, or abiotic causes such as leaving an item on the lawn for some time and inappropriate use of garden chemicals such as fertilizers and herbicides.
It's important to...
Identifying nontarget crop and ornamental plant damage from herbicides has become much easier, with the launch of a new online photo repository by the Statewide IPM Program, University of California Division of Agriculture and Natural Resources.
Dr. Kassim Al-Khatib, weed science professor at UC Davis and Director of the UC Statewide Integrated Pest Management Program (UC IPM), has gathered nearly a thousand photos of herbicide-damaged plants, drawn from his own and others' research. The images are cataloged to show damage that can occur from 81 herbicides in more than 14 specific herbicide modes of action, applied in field to demonstrate the symptoms or when known herbicide...