Ventura County UCCE Staff Research Associate Maren Mochizuki shares with us how monitoring spore traps in avocado orchards can lead to better understanding and management of disease.

An important component of integrated pest management is frequent monitoring to understand which, if any, pests are present and at what time of year.  In collaboration with Akif Eskalen a researcher at UC Riverside, Ben Faber, Ventura County UCCE Farm Advisor and Maren Mochizuki, Ventura County UCCE Staff Research Associate are sampling in three avocado orchards in Ventura and Santa Barbara counties using traps that catch spores, reproductive structures for many disease-causing organisms in avocado such as Dothiorella and Phytophthora

The spore traps consist of glass microscope slides suspended at two heights in the avocado tree canopy.  Every two weeks, we remove the slide and replace it with a fresh one; researchers at UC Riverside examine and identify the spores under a microscope.  We hope to improve our understanding of the life cycles of these spore-producing organisms for more effective disease management.

Young avocado tree killed by Dothiorella canker,

White, powdery exudates from a Dothiorella canker

Healthy green avocado foliage (right) next to the pale, yellow foliage of a tree with Phytophthora root rot

To protect water resources and comply with increasing regulation, greenhouse managers are wise to make changes to prevent pollutants, such as fertilizers, pesticides, and container media from ending up in surface and ground waters. One way to do this is to use vegetated buffers.

Vegetated buffers are areas or strips of land maintained in permanent vegetation to prevent erosion and improve water quality by trapping and treating contaminants. Vegetative buffers can also provide many other benefits such as increasing beneficial insects for biological control of crop pests and protecting streambanks. In addition, they can be used for green waste and secondary crop production.

Some examples include vegetated buffers are bioswales, vegetated filter strips, and constructed wetlands.

• A vegetated bioswale is a stormwater conveyance system that channels stormwater. This type of buffer system improves water quality by reducing flow velocity and increasing sedimentation, filtering pollutants, and allowing infiltration into the underlying soils.

• A filter strip is a band of vegetation that can be used between a greenhouse and a waterbody. The purpose of the filter strip is to slow runoff from the production area and trap sediment, fertilizers, and pesticides before they reach surface water.

• A constructed wetland is an artificial marsh or swamp for treating wastewater, controlling flood waters, and reducing erosion. In greenhouse production, they can be built to further remove pollutants in the effluent from a retention basin.

Although there are different types of vegetative buffer systems, most work in a similar manner. Runoff containing soluble nutrients and pesticides, and sediments with adsorbed pesticides, enters the buffer. Vegetation in the buffer slow surface flow and sediments drop out. Some water infiltrates into the root zone and subsoil, while the remainder becomes lateral subsurface flow. When the roots of buffer plants grow to sufficient depth, they intercept infiltrated water, taking up the soluble nutrients and pesticides. Pesticides adsorbed to soil particles become trapped in the root zone, and high soil organic matter provides conditions for denitrification and pesticide degradation.

Things to consider before constructing a vegetative buffer.

When planning and designing a vegetative buffer, it is best to consult a licensed engineer or the Natural Resources Conservation Service (NRCS). Buffers need to be designed and constructed to comply with all federal, state, and local laws and regulations.

Plant species that are used in buffers should be selected based on their adaptability and tolerance to site conditions. Check local information sources, such as the NRCS and Cooperative Extension, before making selections. Some points to consider are: cost, growth rate, potential of plant invasiveness if not using native plant species, and the ability to use the buffers for producing secondary crops. Growers who are interested in developing techniques to produce secondary crops in vegetative treatment systems should contact Cooperative Extension and the NRCS for guidance.

Planting should be timed so buffers are established prior to expected runoff. Maintenance of vegetative buffers is necessary to sustain buffer function and effectiveness.

The information above was extracted from a larger document, written by Ventura County Cooperative Extension Farm Advisor, Julie Newman. Please contact us if you would like to read the original document in its entirety.

The following Featured Club Happenings was submitted by Piru 4-H Club President, Kris Dewey.

It has been a busy year for Piru 4H! Our members have been provided many educational opportunities because we have a fabulous group of project leaders.

• Our geology project has visited the Santa Paula Oil Museum.
  

• The Cultural Appreciation project attended a Renaissance Fair.
  

• Our swine group is as big as ever and toured a local butcher shop.

• We have two members in the beef group taking animals to the fair in August.
  

• The teatime participants have been learning proper etiquette and took turns hosting tea parties.
  

• Several scrapbooking members took field trips to scrapbooking shops and had a great time learning how to showcase their favorite photos.
  

• We had a cake decorating group that made wonderful snacks for our general meetings.
  

• Our fishing group went on camping field trips and had a great time learning how to bait and cast hooks.
  

• The community service project members participated in TOTSOCE (Trick or Treat So Others Can Eat), made Christmas Baskets and Valentines for U.S. military veterans, and most recently helped sort clothes and other donations and serve lunch at a homeless shelter in Ventura.
  

• We offered the members and their parents the opportunity to attend a CPR class.
  

We are planning a year-in-review to celebrate the successes of this year after the Ventura County Fair and wish all of you a great 2010 season!

Featured Club Happenings are a regular feature in Clover Lines, our 4-H newsletter. Back issues of Clover Lines can be found on our website.

UC has a great web site designed to inform the public and other UC scientists about the research they are doing related to climate change in California. It can be found at http://groups.ucanr.org/CAClimateChangeExt.

The site was designed by Monique Myers, UCCE coastal community development advisor for Los Angeles and Ventura counties, and Susan Schlosser, UCCE marine advisor for Humboldt and Mendocino counties. “The objective is to raise awareness and get good science-based information out to the public. By expanding the site to include pages that highlight researchers doing California climate change research at UC, I think the info will be useful to other UC researchers,” Myers said.

The site is extremely interesting and features researchers covering many fields including: plant science, biometeorology, hydrology, sustainable energy, oceanography, environmental policy, climatology, geochemistry and much more. Information can be viewed in text format, or by watching video interviews with the researchers. The interviews are segmented into “Quick Topics” which are about 2-3 minutes in length. Not only do the interviews extend information, but the researcher’s positive commitment and passion on the issues add a powerful and personal touch. Examples of Quick Topics include: Climate Change Impacts on Water Supply, The West is Particularly Vulnerable, Emissions Trading, Transportation Solutions, and Carbon Footprinting.

Further information about the scientists and their research projects and publications is easy to find. A section of further links provides direction for additional learning.