Posts Tagged: citrus
It's winter time and avocados and other subtropicals are prone to frost damage. Little trees especially that haven't developed a canopy that can trap heat are the most prone. So it gets cold and all the orchard looks fine, but there's one tree that doesn't look right and in a couple of days it really stands out.
Here's an example of a year old tree that turned brown and it actually looks like it was doing better than the trees surrounding. It's bigger and has a fuller canopy..... or at least it did.
But there's all the symptoms of frost damage - bronzed leaves and dead tips.
A week after the cold weather, there is already sunburn damage on the exposed stems. See the brown spots on the upper fork? That will soon turn all brown and dry up.
This is still a healthy tree with green stems, in spite of the burned leaves. Now is the time to protect the tree from sunburn damage. This is what can kill the little tree. Time to white wash it.
Why did it happen to this one tree? Maybe it was a little bigger and needed more water than the surrounding trees. Maybe sitting on a rock and didn't have enough rooting volume for water. Maybe a touch of root rot (although the roots looked pretty good even for winter time). And there were ground squirrels in the area. Easy to bklamne them.
Listen to the sound of winter frost control
And when freeze damage gets extreme
SWEEP and Healthy Soils Grants
February 14, 2018
University of California Cooperative Extension
Ventura County Farm Bureau
Ventura Co. Resource Conservation District
CA Dept of Food & Agriculture
Why: Apply for CDFA funding- State Water efficiency and Enhancement Program (SWEEP) and Healthy Soils Program (HSP).Receive up to $100,000 in grant funding to improve your on-farm water and energy efficiency and healthy soil practices through the grant funding programs. During the workshop irrigation specialists will:
- Provide a comprehensive review of SWEEP/HSP and summary of other CDFA Climate Smart Grant programs
- Guide you through the required water savings and greenhouse gas reduction calculations
- Show you how to assemble a strong grant proposal
When: Thursday, February 14, 2019
2:00 PM - 4:00 PM
Where: UC Cooperative Extension office, 669 County Square Dr., Ventura 93003. California Conference room
Presenters: Andre Biscaro, Irrigation and Water Resources Advisor
Jamie Whiteford, Irrigation Specialist, Ventura/Cachuma RCDs
Khaled Bali, Irrigation Specialist, UC Kearney Agricultural Research and Extension Center
Daniele Zaccaria, Agricultural Water Management Specialist, UC Davis
Registration: To register go to: https://www.eventbrite.com/e/sweep-and-healthy-soils-grants-opportunity-workshop-tickets-54711473490
Questions: Contact Andre Biscaro, 805-645-1465, email: firstname.lastname@example.org
Grant info.: Applications are due March 8, 2019 online at
The SWEEP/HSP provides financial assistance in the form of grants to implement irrigation systems that reduce greenhouse gases and save water on California agricultural operations. Eligible system components include (among others) soil moisture monitoring, drip systems, switching to low pressure irrigation systems, pump retrofits, variable frequency drives and installation of renewable energy to reduce on-farm water use and energy.
Please feel free to contact us if you need special accommodations.
Free One-On-One Technical Assistance to Apply for Grant Funds
Need help in developing and /or submitting your project proposal? Schedule your free one-on-one Technical Assistance session, contact your local UC Cooperative Extension Office for additional information at 805-645-1465
The University of California prohibits discrimination or harassment of any person in any of its programs or activities. (Complete nondiscrimination policy statement can be found at http://ucanr.org/sites/anrstaff/files/107734.doc). Inquiries regarding the University's equal employment opportunity policies may be directed to Affirmative Action Contact and Title IX Officer, University of California, Agriculture and Natural Resources, 2801 2nd Street, Davis, CA 95618, (530) 750-1397; email@example.com.
UC Ag Expert talks about Fuller rose beetle
Date: January 23, 2019
Time: 3:00 PM - 4:00 PM
Contact: Petr Kosina firstname.lastname@example.org
Sponsor: UC Ag Experts Talk
Register in advance for webinar at
Participants of this webinar will receive 1 DPR hour of 'Other' CE units and 1 CCA hour of IPM CE units
Note: This webinar has no fee.
Dr. Beth Grafton-Cardwell, citrus IPM specialist and research entomologist, will discuss the lifecycle, damage to citrus, monitoring, methods of control and export issues associated with Fuller rose beetle. Participants can use the chat function of the webinar to ask questions.
fuller rose beetle
It is that time of year and we should be alert to threat of freezing weather and damage to trees. Last winter was one of the warmest on record, but there was still a sneak cold blast around December 25 that caused some problems in some areas. Wet winters tend to have lower frost threats, and even though wet is forecast for this winter, the forecast is erratic, as usual. That still leaves January which historically is when most of our damaging frosts occur. Fox Weather on the CA Avocado Commission is forecasting some cold weather coming up, so growers need to be prepared for the worst.
Here are some links to frost information, preparing for frost and managing frost damage to trees.
A Frost Primer
The forecast is for north winds, which often means cold, dry air and often with winds. Winds mean no inversion and no warm air that can be introduced at ground level to warm trees. If this occurs, running a wind machine can make the damage worse. Wind machines and orchard heaters work on the principle of mixing that warmer air higher up – 20-100 or so feet higher than ground level which has colder air. When temperatures drop, the air is dry (wet-bulb temp below 28 deg F) and there is no inversion, running a wind machine can just stir up cold air and cause worse conditions (freeze-drying). It's better to not run the machine. The only thing left to do is to run the microsprinklers during the day so that the water can absorb the day's heat. Then turn the water off before sunset so that evaporative cooling from the running water isn't accentuated. Then when temperatures drop near 32 at night and the dewpoint is much below that, it's time to start the water again and let it run until sunrise (when risk is less). Running water works even if the water freezes. This is due to the release of heat when water goes from liquid to frozen state. This 1-2 degrees can mean the difference between frost damage and no damage. Also, ice on fruit and leaves can insulate the fruit. As the ice melts at the surface of the plant, it releases heat, protecting the plants. If there is not sufficient water to run the whole orchard, it's best to pick out the irrigation blocks that are the coldest or the ones you definitely want to save and run the water there continuously. Running the water and turning it off during the night to irrigate another block can lead to colder temperatures in both blocks.
Keep warm this winter.
and check out this Wind Machine You Tube:
Wind Machine frost
“Wood chip mulches will decrease soil nitrogen and spread pathogens” A Misunderstanding that is addressed below by:
Chalker-Scott, L. , Extension Specialist And Associate Professor, Washington State University
Downer, A.J., Farm Advisor, University of California
With chronic drought and/or record-breaking summer temperatures making it increasingly important to conserve water, many gardeners and groundkeepers are using landscape mulches. The ideal landscape mulch not only moderates soil temperature and conserves water, but also:
- reduces compaction;
- provides nutrients;
- enhances plant growth;
- provides habitat for beneficial insects;
- helps control weeds, pests and disease; and
- reduces the need for pesticides and fertilizers.
In addition, landscape mulches should be readily available, affordable, and easy to apply and replace. A review of the literature on landscape mulches (Chalker-Scott, 2007) determined that organic mulches are overall the best choice, with deep layers of coarse woody material providing most or all of the above-listed benefits. Arborist wood chips (created from leaves and branches chipped up by tree service companies) are a particularly good option as they are generally inexpensive and easy to obtain anywhere trees are managed.
Fortunately, none of these concerns are validated by research. Here are some brief explanations (Chalker-Scott, 2007) targeted to our audience:
- Wood chips will not draw nitrogen from the soil unless they are incorporated into it. When used as mulch, arborist chips have no effect on underlying soil nitrogen levels, except to increase them over time.
- Wood chip mulches, even those made from diseased trees, will not transmit pathogens to healthy plant roots. If diseased chips are incorporated into the soil they could infect plant roots, but field evidence of this is rare. Arborist chips that are stockpiled even for a few days undergo severe pathogen reduction through microbial attack within the pile (Downer et al., 2008).
- Wood chips, or any other organic mulch, will not change the pH of the soil. The soil volume is vast, and any acidification would occur only at the mulch-soil interface where it would quickly be neutralized.
- Wood chips, even those made from black walnut or cedar, will not kill landscape plants. There is no reliable evidence that chemical inhibition from decaying wood actually occurs in a landscape situation.
- Wood chip mulches do not lend themselves to tunnel building like landscape fabric and other sheet mulches do: they collapse. Termites do not eat wood chips unless they have no choice; they are negatively affected by some of the chemicals wood contains. In fact, arborist chip mulches house a number of beneficial insects and other species that naturally control pests.
For arborist wood chip mulches to be the most effective (Chalker-Scott, 2007), they should be:
- coarse – no less than ½” diameter – so water and air can move freely through them;
- applied as soon as possible after chipping both to maximize the materials available to microbes and to capture the nutrients released by their activity in the soil; and
- maintained at a depth of at least 4” to prevent weed growth.