IN THIS ISSUE:

CROP ESTIMATE REVISIONS
WEATHER
LATE SEASON MITE DAMAGE
PREPARATIONS FOR THE COMING SEASON
A NEW CISSUS SPECIES
CROP UTILIZATION
COMING EVENTS

CROP ESTIMATE REVISIONS-

At the December 12, 2003, update, the USDA made a few changes in the citrus crop forecasts for Florida. Early and Midseason oranges dropped by 3 million boxes, while Valencia oranges increased by 3 million boxes, leaving the total Florida orange crop unchanged. However, the Florida grapefruit estimate was lowered by 1 million boxes to 41 million. The decrease occurred because of smaller than expected fruit size.

The Texas estimates were unchanged.

WEATHER-

December saw a couple of cold fronts that pushed into the Valley, lowering temperatures to frost levels. There was no apparent damage to citrus, but sugar cane did get burned-both mature cane and the newly planted fields. Overall, the cooler temperatures have increased the coloring of citrus and should bode well for a good spring bloom.

Rainfall has not been common since the end of the rainy spell in September and October, so growers have had to resume irrigation in some orchards.

Both California and Florida experienced some cold temperatures last month, but no significant damage to citrus occurred, as the temperatures were either not low enough or were not of sufficient duration to cause damage except in very isolated cold pockets.

As this is written, another strong cold front is buffeting into the Valley. However, the forecasts are calling for lows in the 40's and 50's for the rest of the week, so even tonight?s full moon won?t be significant. (There appears to be a strong relationship between a full moon and extremely cold temperatures in South Texas.)

LATE SEASON MITE DAMAGE-

Despite the best intentions of growers and caretakers, the prolonged wet conditions of September and October resulted in some severe russeting of fruit as rust mites proliferated under conditions that growers simply could not control. The damage was done before grove soils dried out enough to support spray operations.

In many cases, the damage is concentrated in only parts of a grove, which explains why packouts can vary so widely between different loads picked and run through the packinghouse over several days. Those loads coming from the most damaged areas have lower packouts than those coming from the rest of the grove.

Regardless, even pockets of damage will lower the overall packout and the ultimate return to growers will also be lower.

PREPARATIONS FOR THE COMING SEASON-

With all the talk about crop estimates, packout problems and so on, it seems an unlikely time to begin thinking about next season, but bloom will be on us almost before you know it. Navels normally start in late February, with oranges right behind and grapefruit coming near mid-March. Over the next few weeks, growers will be applying fertilizer and herbicides, and irrigation will begin in the absence of sufficient rainfall.

For the nutritional program, I still recommend split applications of nitrogen fertilizer, as the benefits of splitting far outweigh the potential cost of making a second trip through the grove. For whatever reason or reasons, sheepnosing of Rios is not as severe as in some past years?and growers should do what they can to keep it that way. About the most growers can do about sheepnosing is to adjust nitrogen fertilizer levels to the amount of fruit set?and you cannot determine set until the end of the final fruit drop period shortly after the middle of May.

A light set requires less nitrogen, while a heavy set will need more. The problem comes when growers use the normal (or maximum) amount of nitrogen pre-bloom, but fruit set is lower than normal. Consequently, the excess nitrogen promotes overly vigorous growth (which will result in a heavier than normal set the following year, i.e., alternate bearing) and increases the relative severity of sheepnosing in the current year, i.e., lower packouts.

In general, based on 150 pounds of nitrogen per acre as being normal, about 100 pounds should be applied pre-bloom. Then, if the set in May is deemed to be normal, come back with 50 more pounds of nitrogen at that time (if set is exceptionally high, you might kick that up to 75 pounds). Conversely, if set is considered to be below normal, forget about applying any additional nitrogen this season.

If you have a lot of acres to cover (and even if you don't), you should take a close look at Xtend fertilizer. It does cost a little more than ammonium sulfate, but it has two big plusses it can lay on the grove soil surface for weeks without significant volatilization loss of the nitrogen (and surely the grove will receive rainfall or irrigation within two or three weeks of application) and it contains a significant amount of organic matter, which is especially good for our soils and conditions. Even with Xtend, however, I still advocate split applications.

A NEW CISSUS SPECIES-

Vic French showed me a couple of pictures of a vine that he had encountered in a couple of local groves recently, wondering if I knew it. I didn't, but suggested that it looked a great deal like a close relative of possum grape (Cissus incisa), a woody vine that is very difficult to control in Valley orchards.

Subsequently, Vic reported in the December Citrus Center Newsletter that Dr. Robert Lonard of UTPA and Dr. James Everitt of USDA-ARS have identified the new specimen as Cissus sicyoides. Being native to tropical Mexico, Central America and the Caribbean, it is curious how it got here. I have no doubt as to how it will spread, however?birds eat the ripe fruit and then nature takes its course.

Like possum grape, the vines send down tendrils from the canopy, which tendrils then root. While I don't know for sure, I suspect that it has rather large, fleshy storage organs below ground, just as does possum grape. Other similarities include nearly identical flowers and grape-like clusters of green fruit (berries) that become shiny black at maturity. The major difference is in the foliage while possum grape has a fairly small, thick, fleshy leaf shaped much like a grape leaf, the Cissus sicyoides leaf is large and succulent, and somewhat ovate in shape.

Given the close similarity between the two species, I fear that control of the new vine will be just as difficult as it is with possum grape and I have not managed to eradicate that vine, despite two years of trying various herbicides and management options. The best control will be accomplished by the prevention of seed germination in the groves past experience suggests that materials such as Hyvar, Krovar, and Solicam may be the most effective in preventing the germination of possum grape seeds in the grove. Killing established vines, however, is still not achievable with any of the herbicides I have been testing.

CROP UTILIZATION-

According to Texas Valley Citrus Committee's Fresh Fruit Utilization Report No. 12 for shipments through December 27, 2003, fresh shipments of Texas citrus is closing in on last season's levels. Grapefruit movement was up about 1.3 percent over last season, while export grapefruit is up about 4.7 percent.

Oranges are still slow, with earlies being down 10.7 percent and navels lagging by 6.4 percent. However, the volume of grapefruit in comparison to oranges is such that total domestic shipments are down only about 1.6 percent; factoring in exports lowers the deficit to about 1.3 percent of last season.

One measure of overall fruit quality can be gleaned from the amount of fruit that goes to processing. For grapefruit, processing has accounted for only about 63 percent as much fruit as it did last season, echoing what I have been saying about better Rio Red fruit shape this season. While oranges might appear to be a little better, with only about 90 percent as much of the orange crop processed as last year, it's really a misleading comparison, inasmuch as fresh orange shipments are only about 91 percent of last season.

COMING EVENTS-

The Eighth Annual Red Grapefruit Golf Tournament is set for January 23 at the McAllen Country Club. Contact Texas Citrus Mutual for details.

The Texas Citrus Fiesta is scheduled for the last days of January. Of significance to many of us, the Citrus Fiesta Youth Show, scheduled for January 30, means that area youth will be calling on growers for permission to collect fruit of different varieties in your groves.

(On that note, as one of the people responsible for assuring that any specimen being exhibited is, in fact, the variety that the entry form claims it to be, I would encourage growers to clearly convey the variety name to any youth you allow to collect in your grove?and be sure to point out if there are any off-variety trees in the block. Most mislabeled entries result because of exhibitor error, but a few may be because the exhibitor collected fruit from an off-variety tree within a grove.)

There will be a Valley Water Summit on February 17 at Marine Military Academy in Harlingen. The agenda and list of confirmed and invited officials are impressive. Registration is a mere $49, payable to the Lower Rio Grande Valley Development Council.

Looking further into the future, the Texas Citrus Mutual Mid-Year meeting is set for March 26 at the Citrus Center. Program details will be forthcoming from Mutual as the registration deadline approaches.

Finally, the Texas Produce Convention is scheduled to return to San Antonio on August 12-14-just in case you've been wondering when and where it will be this year.

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


THE INFORMATION GIVEN HEREIN IS FOR EDUCATIONAL PURPOSES ONLY. REFERENCE TO COMMERCIAL PRODUCTS OR TRADE NAMES IS MADE WITH THE UNDERSTANDING THAT NO DISCRIMINATION IS INTENDED AND NO ENDORSEMENT BY THE COOPERATIVE EXTENSION SERVICE IS IMPLIED.


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