- Author: Sonia Rios
The California Avocado Commission is joining forces with Kevin Turner, UC Cooperative Extension goldspotted oak borer (GSOB) program coordinator (http://ucanr.edu/sites/gsobinfo/) in producing and distributing a number of roadside signs to help control the movement of pest infested firewood.
They are asking for avocado grower's participation in areas that are susceptible to the GSOB and/or the Polyphagous Shot Hole Borer (PSHB). GSOB susceptible areas include oak woodlands and forests while PSHB environments include avocado groves. Some of these susceptible locations are primarily focused in the Fallbrook, Escondido, Valley Center, and Alpine areas. Eventually signs will be developed that will feature both the GSOB and the PSHB and discourage movement of oak and avocado wood.
The signs can go in a variety of frame designs. Most signs are 4' x 8'and are normally inserted into a redwood frame, but can be as simple as posts and a piece of exterior plywood onto which the thin aluminum sheet sign can be attached. The signs should be placed visibly along major roadways or busy streets.
If you would like to participate by permitting signs to be placed on your property along major streets, please contact:
Kevin Turner, GSOB Program Coordinator, UCCE/UCR
Soil likes to be covered at all times. It doesn't “want” to be exposed to the elements, so you either cover it (plants, asphalt, paper etc.) or it will cover it for you with plants (weeds). If it can't be covered fast enough, it disappears – erodes. This can be from wind or rain or just natural movement down slope. Plants that are managed for other than their agricultural return are called cover crops, although they can also have a crop that is saleable. Often weeds can be managed to be a cover crop, as well.
We are looking at a possibly wet winter and many tree crops grown on hillsides and sloping ground are prone to soil erosion. Covers can be grown year round, but that usually means they require water all year round. That means they need an irrigation system dedicated to their needs. It also means having extra water which may be limiting.
A winter cover crop that grows out in the winter, does its thing (although that “thing” can include lots of other things, e.g. insectary, nutrients, water retention, etc.), and then dies or goes dormant, can be ideal. It also requires less water than a permanent cover.
But there is a big problem here. Establishment of an introduced cover still requires water. Rainfall in Southern California is erratic and there may be early rains to germinate seed, but it may not be consistent enough to get the plants established. In fact, they may die for lack of further rain or be delayed.
Delayed germination means that soil is cooler and there is less growth. The real growth may occur after there has been sufficient rainfall by January and February when the soils are cooler and there is even less chance for growth
So when rainfall is doing its worst, there's no effective cover. Or what cover there is, is what has germinated from “native” seed. It may not have the characteristics you want for management: low stature, low entanglement with the trees, low water use, holds the soil without holding up harvest, etc.
So what do you do? There are several approaches. You can move the sprinklers out into the middles and irrigate up the seed. If you are in a limited water situation, you can do alternate middles, not cover cropping the whole area, or every third middle. Whatever it takes to break the surface flow of water. Or you can turn to mulching. Put down sufficient mulch in a middle or every other middle to break overland water flow.
Cover cropping is easier than mulching, but it takes water and timing.
Below are two websites with descriptions of cover crops and how to distinguish them from “weeds”. Often a good cover can be the residential weeds. A low–lying cover allows pickers in to get lemons without mess and fear of snakes. It also means that it can be more easily treated (mowed, weed whipped) at the end of the rainy season to reduce fire hazard.
1) Characteristics of different cover crops
2) Weed identification from the UC IPM
APHIS is proposing to amend its fruits and vegetables regulations to allow the importation of avocados from continental Spain into the United States. (This proposal does not include avocados from the Balearic Islands or the Canary Islands.)
As a condition of entry, avocados from Spain would have to be produced in accordance with a systems approach that would include requirements for importation in commercial consignments; registration and monitoring of places of production and packinghouses; grove sanitation; and inspection for quarantine pests by the national plant protection organization of Spain.
Consignments of avocados other than the Hass variety would also have to be treated for the Mediterranean fruit fly (Medfly) either prior to moving to the United States or upon arrival prior to release. Consignments would also be required to be accompanied by a phytosanitary certificate with an additional declaration stating that the avocados were grown and inspected and found to be free of pests in accordance with the proposed requirements.
This action would allow for the importation of avocados from Spain into the United States while continuing to provide protection against the introduction of quarantine pests.
We will consider all comments that we receive on or before April 1, 2013.
You may submit comments by either of the following methods:
- Federal eRulemaking Portal: Go to http://www.regulations.gov/#!documentDetail;D=APHIS-2012-0002-0001
- Postal Mail/Commercial Delivery: Send your comment to
Docket No. APHIS-2012-0002
Regulatory Analysis and Development
APHIS PPD Station 3A-03.8
4700 River Road Unit 118
Riverdale, MD 20737-1238
Supporting documents and any comments we receive on this docket may be viewed at http://www.regulations.gov/#!documentDetail;D=APHIS-2012-0002-0001 or in our reading room, which is located in room 1141 of the USDA South Building, 14th Street and Independence Avenue SW., Washington, DC. Normal reading room hours are 8 a.m. to 4:30 p.m., Monday through Friday, except holidays. To be sure someone is there to help you, please call (202) 799-7039 before coming.
- Author: Cheryl Reynolds
The UC Statewide Integrated Pest Management Program (UC IPM) put together a 26-page card set in English and Spanish on understanding pesticide labels. Intended for pesticide handlers, applicators, safety trainers, and pest control advisers (PCAs), the cards explain when to read the label, describe what kind of information can be found in each section of a pesticide label, and point out specific instruction areas so that applicators can apply pesticides safely and avoid illegal pesticide residues.
Traces of pesticide residue are normal and even expected after pesticides are applied to food crops, but by the time produce is ready to be sold, purchased, and consumed, residues are usually far below the legal limit.
by Cheryl Reynolds, UC Statewide IPM Program
In its latest report from 2013, the California Department of Pesticide Regulation (DPR) reported that there was little or no detectable pesticide residue in 97.8% of all California-grown produce. This demonstrates a strong pesticide regulation program and pesticide applicators that apply pesticides safely and legally. However, there have been instances in California where a pesticide not registered for a specific crop has been used unintentionally, resulting in illegal residues and eventually crop loss and destruction.
The Environmental Protection Agency (EPA) sets tolerances for the maximum amount of pesticide residue that can legally be allowed to remain on or in food.
DPR regularly monitors domestic and imported produce for pesticide residues and is considered the most extensive state residue-monitoring program in the nation.
The primary way pesticide applicators can assure that they make proper applications and avoid illegal pesticide residues is to follow the pesticide label. UC IPM's new card set was developed from information in the upcoming third edition of The Safe and Effective Use of Pesticides as well as Lisa Blecker, UC IPM's Pesticide Safety Education Program coordinator. Bound with a spiral coil, this eye-catching instructional card set was designed for both English-speakers and when flipped over, for Spanish-speaking audiences as well. UC IPM also plans to release a new online course on preventing illegal pesticide residues sometime late fall.
To download copies of the card set in English or in Spanish, see the UC IPM web site.
Oh, oh is there going to be a wet fall and winter? If it comes and washes the accumulated salts of the last four years out of the root zones of citrus and avocado, that's a good thing. But what happens if there is a little too much of the good stuff? In the winter of 2005, Venture got over 40” of rain, which is 200% of what is normal. The last time big rains occurred prior to that was in the winter of 1997-98. That year the rains were evenly spaced on almost a weekly basis through the winter and into the late spring and over 50" fell. That year we had major problems with both citrus and avocados collapsing from asphyxiation. The same occurred in 2005, but not so pronounced. This winter could also see some collapse.
Asphyxiation is a physiological problem that may affect certain branches, whole limbs or the entire tree. Leaves wilt and may fall, the fruit withers and drops and the branches die back to a greater or lesser extent. The condition develops so rapidly that it may be regarded as a form of collapse. Usually, the larger stems and branches remain alive, and after a time, vigorous new growth is put out so that the tree tends to recover.
Asphyxiation is related to the air and water conditions of the soil. The trouble appears mainly in fine-textured or shallow soils with impervious sub-soils. In 1997-98, this even occurred on slopes with normally good drainage because the rains were so frequent. When such soils are over-irrigated or wetted by rains, the water displaces the soil oxygen. The smaller roots die when deprived of oxygen. When the stress of water shortage develops, the impaired roots are unable to supply water to the leaves rapidly enough and the tree collapses. The condition is accentuated when rainy weather is followed by winds or warm conditions.
Canopy treatment in less severe instances consists of cutting back the dead branches to live wood. If leaf drop has been excessive, the tree should be whitewashed to prevent sunburn. Fruit, if mature should be harvested as soon as possible to prevent loss. In the case of young trees, less than two years of age, recovery sometimes does not occur, and replanting should be considered if vigorous regrowth does not occur by July.
Asphyxiation can be reduced by proper planting and grading. If an impervious layer is identified, it should be ripped prior to planting. The field should be graded so that water has somewhere to run off the field during high rainfall years. Heavier soils might require planting on berms or mounds so that the crown roots have a better chance of being aerated.
Post-plant, if an impervious layer can be identified and is shallow enough to break through, ripping alongside the tree or drilling 4-6 inch post holes at the corners of the tree can improve drainage. It is important that the ripper blade or auger gets below the impervious layer for this technique to be effective.
We don't know what the future holds. Hopefully rain that does some good without too much harm.
Avocado asphyxiation 2005