- Author: Chris M. Webb
Recently our office has had many questions related to powdery mildew. What is powdery mildew? It is a disease caused by powdery mycelial and spore growth most commonly found on leaf surfaces but flowers, fruits and shoots can also be affected.
Powdery mildew is very prevalent in California’s dry summer weather. It may cause leaves to turn yellow, die and fall off. In addition, severely infected plants may have reduced yields, shortened production times, and fruit that has little flavor.
UC ANR has some great publications to help keep this from becoming a problem in your yard. Please see: Powdery mildew on vegetables: Pest notes for home and landscape.
Powdery mildew on ornamentals: Pest notes for the home and landscape or Powdery mildew on fruits and berries: Pest notes for home and landscape for further information.
Commercial growers can find information powdery mildew by crop at UC IPM’s pest management guideline site.
Powdery mildew on rose.
Underside of pepper leaf with patches
of powdery mildew.
Powdery mildew causes irregular
yellow blotches on tomato leaves.
- Author: Chris M. Webb
A team of scientists from the Agricultural Research Service of the U.S. Department of Agriculture and the University of Florida’s Indian River Research and Education Center are studying the use of periwinkle (Catharanthus roseus) to fight Huanglongbing (HLB). HLB is a bacterial disease that threatens citrus crops worldwide. The bacteria is spread by the Asian Citrus Psyllid.
The scientists infect the periwinkle plants with HLB and then run experiments on the diseased plants in an effort to find a way to return the plants to good health. They have used nutrient and soil treatments to regenerate infected plants and have placed cuttings in chemical compounds to search for HLB treatments.
Further information on this research and more can be found in the May 2010 edition of the Topics in Subtropics Newsletter on our website.
Yellowing leaves is one symptom of HLB
Periwinkle shows promise for solutions
to problems caused by HLB
- Author: Chris M. Webb
Anaerobic soil disinfestation is being developed as an ecological alternative to methyl bromide.
It controls a range of soilborne pathogens and nematodes across a range of crops including: onion, tomatoes, strawberries, eggplant, spinach and peppers.
Farm Advisor Oleg Daugovish and collaborators recently held an alternative fumigants update meeting at the Ventura County Cooperative Extension office. Part of the meeting was devoted to anaerobic soil disinfestation.
The presentation has been archived on our website with sound. You may find this presentation and many others on this page of our website.
- Author: Chris M. Webb
Our UC IPM website has great information for managing pests in turfgrass. It is designed for landscape professionals working at golf courses, parks, sports fields, and other lawn areas.
In addition to general information on turf grass management, you will find specific notes on the following:
- Diseases
- Insects and mites
- Nematodes
- Weeds
Home gardeners can find similar information here.
- Author: Chris M. Webb
The global marketplace increases the likelihood of invasive pest and diseases entering California. Invasive pests and diseases can affect agricultural productivity, public health, natural resource biodiversity, and water quality and quantity.
The threat of invasive pests and disease is real in Ventura County. Please do your part in minimizing the potential impacts by:
- staying informed about local invasive pest and disease threats.
- notifying the CDFA or County Ag Commissioner if a suspected invasive pest is found.
- following guidelines and procedures designed to minimize the spread of pests and disease.
The current top invasive pest and disease threats to Ventura County, and what you can do to help, can be found on our previous blog posts.
Monitoring waterways for invasive quagga and zebra mussels
Invasive species in the Santa Clara River