FRESH FRUIT UTILIZATION
THE NEXT CROP
UPDATE ON POTENTIAL INVASIVE PESTS AND DISEASES
PSYLLID CONTROL

FRESH FRUIT UTILIZATION-

Through February 18, total fresh utilization of Texas citrus was up about 13 percent over the same period the year before. Grapefruit movement is still running about 27 percent above last season; navels are about done at 22 percent over last season; early and mids are about equal at 99 percent. Most of the strength for grapefruit is in the domestic market, as grapefruit exports are about 27 percent behind last season.

In terms of fresh versus processed utilization, about 67 percent of harvested grapefruit has gone fresh, as compared to about 55 percent a year ago. The proportion of the orange harvest going to fresh markets is almost 80 percent in comparison to about 70 percent last season at this time.

In terms of overall harvest, the industry has picked about 10 percent fewer tons of grapefruit to date and about 10 percent fewer tons of oranges. In terms of crop estimates, about 30 percent of the estimated grapefruit crop is still on-tree; less than 10 percent of the navel/early-mid supply remains. Valencia harvesting started in mid-February.

Lest such lofty numbers go to your head, comparing grapefruit in the current season with what happened in the 2004-05 season is somewhat deceiving. Look at the table below to get an idea of our fresh fruit shipments over the last six years (the numbers are 7/10 bushel carton equivalents, as reported by Texas Valley Citrus Committee).

1999-00 2000-01 2001-02 2002-03 2003-04 2004-05 2005-06 to mid-February
Grapefruit 6,975,556 7,209,251 7,251,063 5,921,610 6,377,943 4,932,350 3,986,707
Exp. GF 353,492 248,498 295,653 240,794 273,667 941,384 545,897
Total GF 7,329,048 7,457,749 7,546,716 6,162,404 6,651,610 5,873,734 4,532,604
Earlys 1,579,756 1,437,262 1,675,403 1,326,908 1,444,935 1,515,807 1,260,323
Navels 555,372 571,658 650,260 457,070 411,350 451,491 551,073
Valencias 290,154 370,129 306,562 296,151 291,409 327,921 1,980
Total 9,754,330 9,836,798 10,178,941 8,242,945 8,799,300 8,168,953 6,345,980

THE NEXT CROP-

The coldest part of winter occurred a couple of weekends ago, during which time the temperatures barely rose into the 50s for the entire weekend. It was also cloudy with intermittent drizzle. As a consequence, the startup of flush and bloom in navels and oranges was delayed, but navels are coming on now. With any luck, we are done with the cold weather and orange and grapefruit bloom and flush should peak in the next couple of weeks.

Rainfall has been conspicuously absent; nothing but a trace here and there since the end of the traditional late summer-early fall rainy season. Irrigation demand is high and expected to go higher as spring progresses.

Hedging and topping crews are running overtime to try to get the necessary work done before the new bloom, as nobody wants to cut off any new fruit. The obvious merit in hedging before the bloom is undeniable, as that usually results in a little better set of the reduced bloom that comes after hedging. Unfinished grapefruit and almost all Valencias, however, will have to wait until the current crop is off, as the money to mature those fruit has already been spent-it makes more sense to cut off a bunch of newly-developing fruit that doesn't have much value at the present time.

UPDATE ON POTENTIAL INVASIVE PESTS AND DISEASES-

The Florida industry is still trying to determine exactly how it will deal with citrus canker and Asian citrus greening diseases, now that eradication is not within the realm of possibility. Since these two diseases will undoubtedly continue to affect the Florida industry, the concern of the Texas industry is that one or both will appear in Texas. Given the failure to eradicate or even contain Diaprepes (citrus root weevil, among other names) over the last few years, that concern is more than a little justified.

Since the Asian citrus psyllid vector of greening has been in the Valley since 2002, possibly brought in on ornamental nursery plants such as orange jessamine, the concern is whether or not these psyllids already contain the bacterium. In other words, did the psyllids that were introduced into Texas bring the disease with them or were they descended from psyllids that originated on orange jessamine? The bacterium does not transmit from an adult psyllid carrier through its eggs. The present thoughts are that orange jessamine does not host the bacterium, so any nymphs that arose on jessamine likely would not be carrying it.

Although the bacterium may exist in citrus trees for a couple of years or more before obvious symptoms are manifest, we may have caught a break in our efforts to determine whether or not greening is present in the state. As it turns out, the psyllid itself can be assayed for the bacterium; if our psyllids are not carrying the bacterium, then other efforts regarding citrus greening will be tremendously enhanced.

As you may know, we have embarked on an extensive survey for greening-like symptoms in Valley orchards and dooryards, as well as in citrus nurseries and dooryard trees from here to Louisiana. This effort will also involve efforts to ascertain the spread of the psyllid beyond the Valley-since we really don?t know where the pest is at the present time.

As part of the overall effort, Dr. Victor French is prepared to collect psyllid specimens wherever they turn up so as to be able to have them assayed for the bacterium. In that regard, the Citrus Center has prepared a leaflet about psyllids and greening that should be printed in the next few days.

In addition, I have completed a pictorial diagnostic guide to help identify psyllids?it is posted to the Aggie-Horticulture website. This information will be forwarded through the Texas Cooperative Extension network of agents, specialists and Master Gardener volunteers for their help in looking for psyllids outside the Valley. The link is http://aggie-horticulture.tamu.edu/citrus/diagnostics/psyllids/psyllids.htm.

Next, I'll start developing a similar guide for greening and another for citrus canker.

PSYLLID CONTROL-

With all the activity and meetings over the last few weeks, the question arises as to whether to control psyllids. The general response is that psyllid is mostly a "minor" pest in orchards and thus does not really require any special control efforts. That will likely change should citrus greening ever be discovered in the industry. Temik application for nematode suppression and citrus rust mite control is very effective against psyllids. In addition, some growers are fond of Lorsban in the summer for scale control?it also works on psyllids. Other growers who favor summer oil sprays will get pretty good psyllid control there, too. Consequently, most growers will be doing something about psyllids without any special effort and that is likely as it should be at this stage of the program.

Control in citrus nurseries, however, is another matter altogether both those supplying the industry with trees as well as those providing trees for the retail market here and elsewhere across the state. Control should be an on-going program in nurseries, not only to reduce damage to the nursery trees but also to avoid spreading psyllid to other areas. Both Lorsban 4E and Danitol 2.4EC are Restricted Use pesticides which are effective against psyllids.

Among the Non-Restricted Use materials, Admire Pro is a soil-applied systemic material that has excellent residual activity and is well-suited for use in both in-ground and container nurseries. Provado 1.6F is a foliar-applied material that is locally systemic and also quite effective. Dimethoate is a foliar systemic (we used to know it as Cygon, I don't know what name it carries today) that also works.

Testing is currently underway on Citri-King, which is the new version of Pre-Vam for use on citrus. It is a natural oil derived from citrus peel.

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