MARCH, 2008       

VOL. 22, NO. 3                                                                             

IN THIS ISSUE:

SPRINGING FORWARD
GROVE ACTIVITIES
TEXAS CITRUS MUTUAL
TRISTEZA
SEASON PROGRESS

Springing Forward—

The delightful aroma of orange blossoms has been apparent for the last couple of weeks, as first navels and then other oranges have begun to bloom.  Grapefruit won’t be too far behind.  There can be little doubt that spring has indeed sprung.

Another harbinger of spring in South Texas is the appearance of Spanish dagger bloom spikes, and I’ve noted a few here and there.  And what would spring be like here without 30-40 mph winds from the southeast, blowing fruit, tender shoots and flower buds onto the ground?

Next Sunday, March 9, the annual ritual of resetting watches and clocks will need to be done as we return to Daylight Savings Time.  Frankly, I like cell phones and computers, as they automatically reprogram to the time changes without any action on my part.  Not only that, when I travel to a different time zone, my cell phone switches to the time wherever I may be.

We have come a long way from the time when one had to wind the clock before going to bed every night.  Ah, Progress…but there is no changing the aroma of citrus in bloom.

Grove Activities—

Fertilization, irrigation, Temik application, herbicide application and hedging/topping are among the needed grove care operations that are in progress—either having been completed or about to be.  Watering is pretty much established, as is the weed control program. If you are on a maintenance hedging/topping program, you should already have that scheduled for as soon as the harvest is completed.  

Temik.  The choice to use Temik or to go with sprays is strictly up to the grower.  Temik is expensive, and some growers don’t believe they can justify the cost.  Growers should know by now that Temik in early spring will normally replace two ground spray applications—which makes Temik’s cost competitive. 

Temik also provides some control of nematodes, reduces the populations of whitefly, blackfly and other sucking pests, plus it gives some near-intangible growth and production benefits to the trees.  The keys to success with Temik are really simple—use the full rate (33 pounds per acre), incorporate it into the soil at application, and water it in.

Fertilization.  Fertilizer is more expensive than last year—because of the cost of petroleum, since much fertilizer manufacture takes a bit of natural gas.  Still, nitrogen is one of the less expensive grove inputs. 

I am often asked about the need for elements other than nitrogen.  Unless last summer’s leaf analyses showed that one or more elements were low or becoming that way, there is no abiding reason to put them in the program.  Some growers do anyway; whatever makes them happy.

The amount of nitrogen is pretty well established—150 pounds per acre for mature trees.  Justification of higher rates is really hard to come by, but there are cases where lower rates are appropriate. 

Groves under a routine hedging and topping program annually should not receive reduced nitrogen rates.  However, groves where hedging and topping was delayed a couple of years past when it should have been done—and there are some—should not receive the full complement of nitrogen.  Those trees will respond to the necessarily severe cutting by making a lot of lush growth, so they don’t need all the usual nitrogen to make it even worse.  Too, the fruit in such groves will probably experience a good deal of rind coarseness and thickening, including sheepnosing in grapefruit—more nitrogen will only make it worse.

Groves under micro-irrigation should not be fertilized as heavily as those under flood irrigation, especially if a significant portion of the fertilizer is injected into the system.  The logic is that putting fertilizer in the micro-irrigation stream concentrates it in the wetted soil volume where the roots are most concentrated, and fertilizer injection is usually spread over several months, so there is little fertilizer loss.

How much should the rate be reduced in these two scenarios?  About a sixth—to 125 pounds rather than 150.  That won’t save you a lot of money on fertilizer costs, but every little bit helps.

Texas Citrus Mutual—

The 25th  Annual TCM Mid-Year Meeting is scheduled for Thursday, March 27, at the TAMU-K Citrus Center in Weslaco.  A couple of the featured topics are variety improvement (both in Florida and in Texas) and citrus greening from the perspective of Mike Irey of Southern Gardens in Florida.

Registration is $30 for TCM members, with pre-registration being urged so that arrangements for breakfast and lunch can be finalized.  No pre-registration, no food.

Tristeza—

Citrus tristeza virus was detected on some Meyer lemon trees in the Houston area.  Apparently, the trees were destined for the Valley, but the CTV positive assay kept them up there.  There is some confusion as to the facts about this discovery, as it was reported that the trees came originally from a nursery in the Valley.  I am still a little confused about that; I mean, why grow them here, ship them to Houston and then ship them back down here?

In addition, the variety was listed as ‘Improved Meyer’ lemon, but the “Improved” part of the name signifies that it is tristeza-free—which these plants certainly were not.  Several years ago, a nursery in that area was propagating Meyer from one or more stock trees grown on-site for that purpose.  Unfortunately, there was tristeza in the stock, which meant that a lot of propagations of Meyer with tristeza could have been widely distributed in that area (and elsewhere).  The stock was replaced with CTV-free stock, but “Typhoid Mary” may have already been distributed.

Meyer lemon is not one of the varieties that must be propagated from certified sources.  Such being the case, Meyer can still be propagated from whatever source (within Texas) and there is no restriction on where they can be sold.  To move them into the Valley, however, requires that the trees be assayed for CTV (and other things, I suppose).  Stay tuned for further developments, if any.

Season Progress—

Through the middle of February, the industry had shipped about 70 percent of the volume that was shipped all of last season, suggesting that the end of the season might be in sight.  Total utilization to that time figured to about 56 percent of the estimated crop, including fresh shipments, local use and processed volume. 

Given that calculation, there should be a whole lot of fruit still out there.  However, one should remember that the estimate is just that—an estimate. 

The remaining supply of grapefruit (as related to the estimate) is running very close to or a tiny bit higher than last season.  Earlies, however, are down to the single digits as compared to about 20 percent remaining a year ago—and that’s based on a lower orange crop than last season. 

Another key indicator is Valencias—the first shipments this season came during the week ending February 2, but the volume moved in the first couple of weeks of harvest is double that of a year ago.  Essentially, most shippers don’t want to move into Valencias until they have about exhausted the supply of earlies.   

JULIAN W. SAULS, Ph.D.
Professor & Extension Horticulturist
2401 East Highway 83
Weslaco TX 78596