Five Snail Speakers for the Price of One

Snails and Slugs (May 22, 2019 from 3-4pm)

Presenters: (!) Dr. Cheryl Wilen (UC IPM), (2) Dr. Rory Mc Donnell and (3) Dr. Dee Denver (Oregon State University), (4) Dr. Adler Dillman and (5) Dr. Irma De Ley (UC Riverside). The webinar will cover an overview of snail and slug biology, damage and management with emphasis on brown snail and Italian white snail, and current research on slug biocontrol using nematodes. One DPR CE unit (other) and one CCA CE unit (IPM) are approved.

 

And What Else Are the

                   UC Ag Experts

                             Talking About? 

giant land snail

S. California Can Grow Just About Anything including avocado and citrus

It seems the world is attacked on all sides, including the iconic citrus and avocado industries in California. Aside from the other agricultural issues all growers have of water, labor, costs, weather, family, you name it, citrus and avocado growers have particular problems. There is Asian Citrus Psyllid/Huanglongbing for citrus and the Shot Hole Borers for Avocado. The latter is a beast that is going to lay waste to many other tree species besides avocado, like sycamore, coast live oak, native maple and many other tree species.

Citrus and avocado are still strong industries in California and will remain so as solutions to these pest invasions are dealt with. But we are coming up to the time when maybe other tree crops should be considered. These alternative tree crops come with new promise, but they also come with problems. You have to figure out how to market them. The California industry knows what to do with an avocado and a grower knows where to go with a ‘Gold Nugget' mandarin, but what do you do with a longan or cherimoya. You figure out how to market it, through direct marketing at farmers markets or the internet, some specialty marketer like Frieda's Finest or Melissa's or your regular packer who has taken an interest in your product.

I've spoken with growers who say they have grown such and such for four generations and they are not adjusted physically or psychologically to grow anything else. Well, it is good to stick with what you know best and refine it for current conditions, but it's also good to keep options open. Stick to what is best for your situation and support the studies needed to make citrus and avocado strong industries, but also think about maybe something else.

Here's links to tree crops that do well in Southern California and for that matter can be adjusted to much of California. Just watch out, it gets cold north of the Grapevine and San Luis Obispo and options are more limited with subtropicals, but think deciduous.

Subtropicals

http://ceventura.ucanr.edu/Com_Ag/Subtropical/Fruit_and_Nut_Varieties/Citrus_and_Other_Subtropicals/

Deciduous

http://ceventura.ucanr.edu/Com_Ag/Subtropical/Fruit_and_Nut_Varieties/Deciduous/

 

citrus-spinach

Learn About New Produce Marketing Channels in Los Angeles

farmers market

Plant Nutrient Symptoms

 

This is a great website to view plant nutrient symptoms by plant or by nutrient.  It is of ornamental plants, but hey, once you can see it on one plant you will something very similar on avocado, lemon, apple, almond, lychee or whatever alphabetic fruit you work with. Kudos to University of Florida. Of course once you see what iron deficiency looks like, you'll be able to identify it on most other plants:

http://hort.ufl.edu/database/nutdef/index.shtml

 

Below is Boron toxicity from a grower who got too excited about correcting B deficiency,

 

 

boron toxicity citrus

Rehabilitation of Freeze Damaged Subtropical Fruit Trees

For the first time since the great freeze of '89-90, we have experienced a little more than minor damage to our crops. Compared to the San Joaquin Valley, Ventura country escaped without major damage; although there were some areas harder hit like the Ojai Valley and some canyons near Santa Paula. Many parts of the SJV were hard hit.

As in the freeze of 1990, your trees must be cared for in the same way during this post freeze period. In 1990, advice was issued to the grower about the rehabilitation of their trees, both citrus and avocado. We would like to review that information for you at this time. How can we best aid tree recovery so that tree growth and yield will proceed most rapidly?

FREEZE DAMAGE

Citrus and avocado leaves appear wilted or flaccid during periods of low temperature. This is a natural protective response to freezing temperatures and does not mean the leaves have been frozen. Leaves will be firm and brittle and often curled when frozen. Leaves become flaccid after thawing, and if the injury is not too great, they gradually regain turgor and recover, leaving however, dark flecks on the leaves. Seriously frozen leaves collapse, dry out, and remain on the tree. Foliage form recent flushes are most susceptible to this damage. If twigs or wood have been seriously damaged, the frozen leaves may remain on the tree for several weeks. If the twigs and wood have not been damaged severely, the leaves are rapidly shed. Trees losing their leaves rapidly is often a good sign and is not, as many growers believe a sign of extensive damage.

Cold damage to the twigs appears as water soaking or discoloration. In older branches and trunks it appears as splitting or loosening of bark where the cambium has been killed. Bark may curl and dry with many small cracks. Dead patches of bark may occur in various locations on limbs and trunk.

Sensitivity to frost is dependent upon many variables. In general, mandarins are the most cold hardy followed by sweet orange and grapefruit. Lemons are very frost sensitive with Eureka decidedly more sensitive than Lisbon. For avocados, Hass is about as cold tolerant as lemons, while Bacon is more cold tolerant. Limes are the least cold hardy. Healthy trees are more tolerant than stressed ones. The rootstock also imparts sensitivity onto the scion.

Injury to the foliage and to young trees may be immediately recognizable but the true extent of the damage to larger branches, trunks, and rootstocks may not appear for on to four months following the freeze. No attempt should be made to prune or even assess damage from the frost until spring when new growth appears.

WHITEWASHING

The only treatment that should be done rapidly after a freeze is whitewashing. Often the most sever damage following a freeze results from sunburn of exposed twigs and branches after defoliation. Avocados and lemons are the most susceptible to sunburn, oranges not as much; but, if the tree has been defoliated, applying whitewash would be precautionary. Temperatures do not have to be extremely high to cause sunburn.

PRUNING

Pruning should be carried out to prevent secondary pathogens and wood decay organisms from slowing tree recovery. Again, however, there should be no rush to prune. Premature pruning, at the very least, may have to be repeated and, at the worst, it can slow tree rehabilitation. It should be remembered that when pruning, all cuts should be made into living wood. Try to cut flush with existing branches at crotches. Do not leave branch stubs or uneven surfaces. Tools should be disinfected in bleach or other fungicide before moving on to the next tree.

The extent of pruning is dictated by the amount of freeze damage:

Light Damage	Medium Damage	Severe Damage	Extreme Damage
Where only the foliage and small twigs are injured,pruning is not required	Where a considerable part of the top has been killed but the trunk and main crown limbs show little damage, branches should be removed back to living wood above vigorous sprouts	Where the top and crown limbs are severely damaged but there are sprouts above the bud union, the tree should be cut back to the uppermost sprout	Where trees are killed to the bud union or the rootstock has been girdled, the trees should be removed and replaced with new trees

IRRIGATION

Irrigate carefully! Remember that when leaves are lost, obviously evaporation from leaves is greatly reduced, and, therefore the amount of water required is also greatly reduced. A frost-damaged tree will use the same amount of water as a much younger or smaller tree. Over irrigation will not result in rapid recovery. Instead, it may induce root damage and encourage growth of root rotting organisms. This is particularly true for avocados. Irrigation should be less frequent, and smaller amounts of water should be applied until trees have regained their normal foliage development.

FERTILIZATION

Fertilization of freeze-damaged trees should be carefully considered. There is no evidence to indicate that frozen trees respond to any special fertilizer that is supposed to stimulate growth. If trees are severely injured-with large limbs or even parts of the trunk killed-nitrogen fertilizer applications should be greatly reduced, until the structure and balance of the tree become re-established. Trees should be watched for evidence of deficiencies of minor elements. Deficiencies of zinc, manganese, copper, and iron are most likely to develop. For citrus, these materials should be applied as sprays, and they should be used as often as symptoms are observed. Two or more applications may be required the first year.

 

citrus frost

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