IN THIS ISSUE

VALENCIA ORANGE PRODUCTION
EARLY WORK
MARRS VERSUS VALENCIA
VALENCIA VERSUS VALENCIA
VALENCIA VALUE
EXPERIENCE WITH OLINDA
CITRUS PEST UPDATE
CURRENT SITUATION

VALENCIA ORANGE PRODUCTION-

According to the last inventory of Texas citrus, there are approximately 6000 acres of early and mid season oranges, about 3000 acres of navels and only about 1100 acres of Valencia oranges. Many in the industry decry the low Valencia acreage, but few growers are willing to grow Valencias. Similarly, few growers seem overly concerned about the potential problems of marketing the increasingly large navel and early orange crops or about the poor juice yield and quality of the main early orange variety.

Growers have contended that the extended potential freeze risk to the Valencia crop is why they don't grow Valencias-but Valencia growers claim that if you're going to worry about potential freezes, you probably shouldn't be in the citrus business. After all, a major freeze that would reduce the Valencia crop would wipe out the bulk of the grapefruit and early orange crop, leaving only navels that may have been completely harvested at the time of a freeze. Even then, a significant part of the Valencia crop may be salvaged for juice-but you can be sure no grapefruit would be picked for juice. Besides, that is one of the major reasons they sell crop insurance and is a good reason for microsprayers.

Growers also contend that Valencia production is considerably lower than that of other round oranges and especially lower than grapefruit production. I'm not so certain that Valencia production is lower than other round oranges-even if true, the bottom line is not how many tons per acre you produce but rather how much money you make per acre, whether it's oranges or grapefruit.

Early Work-

In early production research, Marrs on Texas sour orange at 163 trees per acre averaged 9.87 tons per acre for the seven years from 1967-1973 in a rootstock trial, with 11.4 tons per acre in the tenth year in the orchard (Wutscher and Shull. 1976. J ASHS 101:158-161.).

In another rootstock trial, Valencia on Texas sour orange at 120 trees per acre averaged only 4.0 tons per acre per year for the years 1967-73, with 6.2 tons per acre in 1973 (Wutscher and Shull. 1973. Proc. TR-ASHS 17:66-73.).

Research in the 1950's showed Valencia on sour orange to average about 4.1 tons per acre from a 1950 planting through the March, 1961, harvest on apparently virus-free scions at 70 trees per acre (Olson and Shull. 1962. J RGVHS 16:40-43).

A comparison of old-line with nucellar Valencia planted in 1958, frozen back in 1962, and harvested in 1966 through 1970 showed an average production of 5.5 tons per acre for old-line versus 3.5 tons per acre for the nucellar line (Wutscher and Shull. 1970. J RGVHS 24:12-17).

While these research results very obviously support the contention that Valencia is not particularly productive in comparison to Marrs oranges, it should be noted that all four of these trials were conducted as rootstock trials (I reported only the sour orange rootstock results) in different orchards at different spacings at different times-and quite likely under different management regimes. Indeed, these studies may have been the basis on which the present contention of low productivity of Valencia was formed. In addition, one of the studies suggested that the primary use of Valencia oranges at the time was for processing rather than for fresh market-which suggests possible lesser orchard care.

Too, these studies were terminated after only five to seven years of production, which is probably inadequate time on which to determine long term productivity. Finally, the closer spaced plantings would easily excel over wider spacings during these early years before the trees achieve full size.

Marrs Versus Valencia-

So, rather than compare apples with oranges, so to speak, let's look at some head-to-head comparisons in which Marrs and Valencia were grown together in the same orchards.

Comparisons of Marrs and Valencia during1969-1975 under different irrigation treatments showed that Marrs averaged 13.73 tons per acre while Valencia averaged 12.88 tons per acre over the first seven years of production (Wiegand and Swanson. 1982. J RGVHS 35:87-95.).

For those concerned about freeze risk, it should be noted that temperatures were less than 26 for six hours during December 21-22, 1973. Marrs had already been harvested (13.4 tons per acre) at that time, but Valencia wasn't harvested until March, 1974 (13.3 tons per acre). The authors did not report on the loss of any Valencia fruit-but one expects to have significant fruit drop after exposure to 26 or lower for six hours.

In addition, such temperatures should have impacted the trees and thereby reduced production in the following season, i.e., 1974 yields. However, Marrs production barely decreased (about 0.7 percent) following that freeze while Valencia production dropped about 13.5 percent. For whatever reason, one of the Valencia irrigation treatments suffered a drop of nearly 50 percent while the other three treatments dropped only about 1.5 percent-which the authors attributed to a poor bloom on the trees of that treatment.

In a large scale test at Weslaco (Rouse, Dean and Gautreaux. 1987. J RGVHS 40:15-22.), Valencia and Marrs production did not different statistically over the 12 years of production records, nor during years five through 12 of production. Marrs was superior to Valencia only during the first four years of production.

Moreover, Marrs production evidenced severe alternate bearing while Valencia production was only mildly alternating. For the record, Valencia averaged 13.12 tons per acre per year over the 12 years, while Marrs averaged 14.45 tons per acre. However, Valencia production during the ninth through 12th years averaged 20.05 tons per acre per year while Marrs averaged 18.28 tons during the same period.

The authors opined that comparisons of productivity should be delayed until the trees have achieved sufficient size and age to be truly representative, since meaningful yields were not obtained until the trees were six or seven years old. In other words, 59 percent of the total Marrs orange production occurred in the last four years as compared to 63 percent of Valencia production having occurred in that period.

Valencia Versus Valencia-

Several years ago, I cited in this newsletter the results of a 16-year production study involving five nucellar and one Texas old-line variety of Valencia orange. The work was started by Norman Maxwell in 1961, but the trees had to be regrown after the 1962 freeze, so production did not commence until 1967 (when Hurricane Beulah decimated Texas citrus production). The production over the following 16 years was published by Maxwell and Rouse in 1987 (J RGVHS 40:23-30.).

Over the 16 years of production, average annual production was 13.80 tons for Olinda, 13.03 tons for Campbell, 12.64 tons for Cutter, 12.55 tons for TAES nucellar, 11.98 tons for Texas old-line and 11.79 tons for Frost. Statistically, Olinda was superior to all but Campbell.

During the first five years of production, average tonnages ranged from a low of 7.07 for the TAES nucellar to a high of 8.43 tons per acre for Olinda. In the second five years of production, the range was 11.56 tons for Texas old-line Valencia to 14.68 tons per acre for Olinda. In the third five years, the range was 14.57 tons for Frost to 16.94 tons per acre for Olinda. In the last two years of the study, average yields ranged from 16.20 for Frost to 18.97 for Campbell.

If one compares just the Texas old-line Valencia with Olinda nucellar Valencia, Olinda produced 0.23 tons more per acre per year during the first five years, 3.12 tons more in the second five, 2.01 more in the third five years, 2.2 more tons per acre in the last two years and an overall average of 1.82 tons per acre for each of the 16 years reported. All of these differences except for the first five years of production were statistically significant.

Valencia Value-

So, not only do Valencias produce nearly the same tonnage as Marrs oranges, some Valencias are more productive than the standard Valencia used in Texas. Now let's compare the possible returns from Marrs and Valencia oranges.

Regular readers know that I have previously decried the situation with respect to Marrs orange acreage and total production as they relate to marketing. I believe that I have established that our Marrs industry is in an alternate bearing situation in which it has been nearly impossible to ship the entire Marrs crop during the heavy "on" years-which the coming season is expected to be.

You may also recall Ben Abbitt's comment at the recent TCM Mid-Year Meeting to the effect that TCX has to buy two pounds of orange solids to blend with every pound of early orange solids extracted by TCX. Too, Marrs produces only about 110-115 pounds of solids per ton while Valencia runs about 135-140 pounds per ton-and does not require other orange solids to blend. Indeed, Valencia solids are typically used to blend with Marrs and other early orange solids in order to bring the quality of those juices up to a marketable level. The point is that early orange juice is not worth as much as Valencia juice.

From survey data compiled by the Texas Citrus Growers League over the last few seasons, it is obvious that growers are receiving significantly higher prices per ton for Valencia oranges than for early oranges. The price differential may well reflect the overall supply-demand curve, in that the supply of early oranges runs from September to February, while the limited supply of Valencias is mostly exhausted in February and March. Both, however, should be about equally impacted by supplies from Florida, which should tend to negate the price differential beyond the normal differential for the juice value of eliminations. Nonetheless, Valencias are worth more than early oranges, for whatever reasons.

Still, the higher value of Valencias does not necessarily translate into greater returns per acre-which should be the major concern of growers. Unfortunately, the survey data from the Growers League does not provide either tons or acres from which returns per acre can be calculated.

A cooperating shipper provided the necessary data to calculate average returns per acre over a large number of acres. During the 1991-92 through 1996-97 seasons, the average production of early oranges was 4.32 tons per acre while Valencias averaged 2.77 tons per acre. Early oranges averaged $101.70 per ton as compared to $190.93 for Valencias. Thus, the average return over the six seasons was $438.95 per acre for early oranges and $529.65 per acre for Valencia oranges.

While the difference in returns is not all that great, being only $90.70, it does show that Valencias are more profitable than early oranges.

Experience with Olinda-

In an orchard for which the records are available to me, early orange production over the last three seasons has averaged 10.19 tons per acre while Valencia orange production averaged 8.77 tons per acre. In 1997-98, the early oranges in this orchard hit 14.75 tons per acre while the Valencia average was 15.22 tons per acre.

Interestingly, the Valencia block in this orchard is comprised of 20 percent Texas Valencia planted in spring of 1988 and 80 percent Olinda Valencia planted in spring of 1990. Harvest records were separated in 1997-98 between the two Valencias so as to compare production. The Texas Valencia made 9.71 tons per acre, the Olinda Valencia made 16.60-which is 1.85 tons more than the early oranges produced per acre.

Interest in Valencia, especially Olinda, has been increasing. To my knowledge, there are only two plantings of it currently, although it is in the budwood program. Both Donald Thompson and I can provide budwood of Olinda.

If Texas Valencia growers were selfish, they would probably not like to see additional Valencia acreage planted. After all, they know they have a crop that is relatively productive, with none of the marketing problems of grapefruit and other oranges, and is more valuable than other round oranges.

CITRUS PEST UPDATE-
Juan Anciso

Although it has been dry for most of 1998, about half of the Citrus IPM program groves have rust mite populations that have warranted a spray application in the month of April. Therefore, this dry weather may mislead many to believe there are very few rust mites and not necessary to spray at this time when in fact many of these groves need close monitoring. Routinely monitoring the groves is essential to cost-effective control of these rust mite populations as well as other pests since they can explode even though weather conditions may not be optimal for that particular pest. The citrus blackfly populations have been increasing in those groves that have had citrus blackfly problems but are still at low levels. Texas citrus mites, armored scale, and whitefly are present but these populations as a whole have been at low levels. Many have treated for armored scale since they were quite troublesome this past year. Although there have been no spring rains, foliar diseases are still at high levels when compared to other years. Melanose and greasy spot are as noticeable as last year when we had the spring rains. Many are considering an oil application in combination with copper in order to manage these diseases. If applying oil this early be sure the trees are not water-stressed since we have been very dry and serious problems could arise even though temperatures have been below 90 F.

CURRENT SITUATION-

To paraphrase a refrain from an old Marty Robbins ballad, "...for the rains that were promised never came, never came, never came". Two good promises during April just fizzled out, with the last one dumping really good rains offshore. The Onionfest was dry again and Cinco de Mayo looks to be.

Water levels continue to decline as heavy irrigation pressure for all crops takes its toll. I've done all I know to do-wash the truck, shine my boots, stuff like that-but it hasn't worked. The onion growers are thankful and I suppose the melon growers hope for continued dry weather as they begin harvest. Actually, we could accommodate everybody but the local ranchers if it would just flood in the watersheds to give us ample supplies to irrigate.

From what I'm told, metered waterings of citrus this spring have been accomplished with less than four to nearly five inches of water-and that is for full irrigations, not strips. This just proves what I have always contended, i.e., citrus irrigations use considerably less water than the median irrigation allotment in a particular district.

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