High priced district water in San Diego County is really making it tough on citrus growers.  Many of the citrus growers in San Diego County are finding it increasingly difficult to make a profit, but they usually stick it out for several years before they turn the water off.  Why do they wait so long?   Market prices may go up for all kinds of reasons including freezes in other parts of California or Florida, or the discovery of illegal pesticide residues in foreign fruit, or an unusual demand for fruit in the U.S.  Sometimes it makes sense to farm organically because the return prices can be high enough to stay in business, but farming expenses may increase and we have often seen yield and fruit quality decline.  However, it may become apparent after awhile that some varieties of citrus, such as Valencia oranges, may be have seen their day and it is time to move on with something else.  So, the water gets turned off.

Areas in the county with good quality and abundant well water will probably stay in the Valencia orange business for some time,  especially with declining acreage in other areas which tends to make orange prices go higher.

Unfortunately, citrus trees usually do not completely die if the water gets turned off.  They struggle to produce a few leaves with water supplied by spring rains.  They don’t produce fruit; they just have a few leaves. 

Normally this wouldn’t be a big deal.  But things have changed in California.  Asian Citrus Psyllid (ACP) has infested hundreds if not thousands of backyard citrus trees in Los Angeles County, and is now spreading through Riverside and San Bernardino counties.  Psyllids are occasionally found in the southern parts of San Diego County and they are being sprayed out by CDFA.  All of a sudden ACP are now being found in quite a few locations in the citrus groves in northern San Diego County (Fallbrook, Pauma Valley and Borrego Springs). 

Asian Citrus Psyllids by themselves don’t do very much damage, but they are the carrier for the Huanglongbing (HLB) disease which is well on its way to killing out a large percentage of the citrus industry in Florida.  We still have not found any HLB disease in California (except for one tree in Los Angeles County, which was removed).

Here’s the Problem!  Dying citrus groves are everywhere in San Diego County; most of them had the water turned off in the last few years when the water districts raised their prices.  And nobody is watching these groves to check for ACP.  And even if they were found, would the grower pay the money to have the trees sprayed?  I doubt it!

So, let’s do the right thing.  In order to protect citrus in California, these dying trees need to be cut down and the stumps either removed or killed.

How can this be done?  When I was younger I cut down my father-in-law’s orange grove in Riverside, so I have some experience (and I still have a sore back).  I cut the trees into fire-place size logs and sold and delivered the firewood.  I cut the trunks off about 3 feet from the ground, and yanked out the stumps with a tractor.  I piled up the stumps and burned them in the winter (you can’t do that in Riverside anymore, but you can in San Diego County in the winter if you have a burning permit from the fire department).  You can also bring in a chipper to chip up the smaller branches and brush.  They even have some giant grinders that will grind the whole tree right down to the ground.

Commercial Growers and ACP.  Over the past several years we have had quite a few meetings for commercial growers on ACP and I would advise all growers (for a refresher course) go to the website http://www.ipm.ucdavis.edu/index.html and click on Exotic and Invasive Pests, then click on Provisional Treatment Guidelines for Citrus under the Asian Citrus Psyllid and Citrus Greening Disease headline.

For homeowners and commercial growers, the basic strategy is to treat the trees with a foliar spray when leaf flush begins in the spring, alternating with a soil treatment with a systemic insecticide.  Homeowners can use carbaryl (Sevin) for the foliar treatment, commercial growers have quite a few choices (refer to the list of pesticides on the University of California’s website at www.ipm.ucdavis.edu).  The systemic should be applied in the summer when the soil warms up; homeowners can us imidacloprid (Bayer Advanced Fruit, Citrus and Vegetable Insect Control), and commercial growers can use Movento, Admire Pro or Platinum.  Make sure you read the labels carefully and apply the correct amounts because some of these materials are toxic to bees.

Task Force Formed.  One of the lessons that came out of Florida was that aerial applications of pesticides should be coordinated so that all of the growers in an area should treat at the same time.  If not, the insects hunker down in the non-treated groves and move back into the treated groves fairly quickly.  So in order to coordinate this effort a task force of volunteer growers along with the Farm Bureau, County Agriculture Weights and Measures Dept., and the CDFA are meeting at the Farm Bureau once a month.  A Regional Coordinator has been hired, Mark Nyberg, who will work with growers to develop treatment plans.  You can reach Mark at (805) 832-3187, or email him at agexpert@dslextreme.com.    You can also find information on the Farm Bureau website www.sdfarmbureau.org. 

Strategy.  The strategy is fairly simple: we hope to keep the ACP suppressed so that the spread of HLB is very slow (when it is discovered here).  And the grower should remove the dead and dying trees.

So, let’s either keep the trees and treat them, or remove them!

An Orange Grove that has had the water turned off for one year.