Valley Citrus Notes

I had not experienced freezing temperatures in February until this year—but it was bitterly cold across the Valley on February 3-5. I recorded lows of 26 on the mornings of the 3rd and the 4th, with 24 the morning of the 5th. I cut ice in oranges on the 3rd, but didn’t do any cutting on the other days.

Listening to the various reports coming in from growers initially led me to wonder if that old saying about fishermen and liars didn’t also apply to citrus growers, as there were more reports of higher minima and no icing than there were of critical temperature minima and icing. But my faith in fellow growers was somewhat renewed as time went on with very little damage to fruit or trees appearing.

To be sure, there have been varying degrees of leaf loss on mature trees—but at least the leaves are falling green rather than turning brown and sticking on the twigs. The latter would represent twig death. To be sure, young trees in some areas did experience some twig damage, but I have not seen twig damage in mature groves.

If you believe it, this winter’s record cold across the country is due to global warming. Seems contradictory to me—but if you believe in global warning, have at it; just don’t bother trying to explain it to me.

Such cold temperatures could not have come at a better time in terms of tree condition—the trees were about as cold hardy as they could be at that time. Too, excepting nursery and a few young trees, buds were not yet starting to show signs of growth when the cold hit. The timing, however, did delay the emergence of the spring flush somewhat.

As a general rule, navel oranges normally bloom soon after mid-February, followed by oranges about the end of February, and grapefruit about the second week of March. While grapefruit bloom may yet come out on time, given the warm weather since mid-February, navels are already about two weeks late and oranges are likely to be close to two weeks late. Popcorn stage buds are scattered in oranges of all types as February ends.

If grapefruit flush is about on time, the resulting shorter period of flush for the overall industry, coupled with the extensive psyllid sprays of November and last month, should result in little psyllid damage to this flush. The logic is that reduced psyllid numbers because of control efforts and a more concentrated flushing period mean that the flush could get past the normal egg-laying period of ACP before remaining ACP can react, thereby reducing the numbers of nymphs on the new flush.

The Maury Boyd cocktail approach to living with citrus greening instead of cutting out and replanting infected trees continues to attract interest. If memory serves, this grove is about 400 acres of Hamlins and Valencias on Swingle rootstock (excepting one Valencia on Carrizo that is losing trees to citrus blight) not too far from Immokalee, FL. The grove planted on double row beds, with microsprayer irrigation throughout.

The grove is essentially 100 percent infected with citrus greening—and you can find the symptoms on practically every tree you examine. At the recent HLB conference in Orlando, Dr. Timothy Spann of the University of Florida at Lake Alfred reported the production of the Boyd grove since the 1999-00 season. He graciously shared the following image with me that I could share it with you.

HLB was confirmed in the grove in early 2006, although it appears that the first symptoms were observed (and marked) in early 2005. Boyd started applying his nutritional cocktail three times a year in the spring of 2006. He also sprays regularly to control the psyllid.

On the graph, the solid lines are Boyd’s production data, the dashed lines are the industry averages for southwest Florida. For the most part, the year to year variations for the Boyd grove parallel those of the industry, i.e., when the industry average was up, Boyd was up and vice versa. For reference, boxes per acre shown on the graph equate to 4.5, 9.0, 13.5, 18.0, 22.5, 27.0, 31.5, and 36.0 tons per acre (100 to 800 boxes, respectively).

Overall, the Boyd Valencias have averaged about 21.5 tons per acre for the period shown, while his Hamlins have come in at about 25.8 tons per acre (I didn’t do the math on the industry averages). Prior to greening, Boyd’s Valencias averaged about 22.3 tons per acre, but have dropped post-greening to about 20.6 tons. I expect that to rise to near 21.0 tons when the current crop is harvested. Don’t forget that he is losing some Valencia/Carrizo trees to blight. However, his Hamlins have increased since greening from about 25.7 to about 26.0 tons.

One other thing about the graphic: If you look at the industry average lines, you should notice that the averages post-greening have dropped substantially from pre-greening levels. That decrease likely reflects the loss of bearing trees to the rogue and replant effort that many growers have practiced.

The current season is over the midway hump, so it is appropriate to look at how it has gone so far. Domestic grapefruit shipments through mid-February were at 97 percent of last season, though export grapefruit shipments were up about 220 percent. Earlies were running at about 107 percent of last season, while navels came in at 130 percent of last season. For all practical purposes, the navel season is over, earlies are winding down ( less than 10 percent of the estimated volume remaining), and grapefruit is about 60 percent harvested to date. Valencias will start up any day now as the remaining earlies are cleared out.

Overall fresh fruit shipments were at 105 percent of last season to date. On the processing side, the volume of earlies (including navels) that had been processed through mid-February was 162 percent of last season. Grapefruit processed volume was 150 percent of last season.

So, despite the increased volumes of processed fruit, fresh sales have pretty much kept pace with last season—irrespective of the lack of movement to California from the first of November to nearly Christmas.

Earl Neuhaus was out in California a few weeks ago and he had the opportunity to sample the Sumo mandarin. A day or two after he related this, David Karp published (in the LA Times) a rave review of the Dekopon fruit from Japan. It’s like a huge mandarin, seedless and easily peeled. The flesh is firm, but melting, intensely sweet with just enough acidity. The rind is rough, but easily bruised. The fruit is somewhat oblate with a very pronounced neck at the stem end.

It originated in Japan as a cross between Kiyomi tangor (orange X mandarin) and ponkan. Originally known as Shiramui, it got the name Dekopon (deko apparently means “bump” and pon for ponkan). It is also grown in South Korea, Brazil, and China. How it got to California is an interesting story in itself, given the presence of severe strains of citrus tristeza virus in Japan.

The initial importation was directly to the California Citrus Clonal Protection Program at Riverside, with virus cleanup to be performed by the CCCP at the expense of the grower. That grower ultimately went under and sold the rights to the present owners. Before they did anything with it, some illegal importations into California were propagated, planted, discovered and destroyed—with severe CTV.
The new owners planted a few hundred acres, mostly in 2008—and this season marked the first significant production of the fruit. In time, it will be made available to other growers, but production from those will be a few years down the road. Meanwhile, the fruit is finding much favor in the few markets where it is marketed in California. If you’d like to know more about it, check out www.sumocitrus.com.

Two medflies were recently trapped in the Pompano Beach area of Broward County, which has resulted in intensification of trapping in that vicinity. The origin of these medflies is unknown.

You might recall that over 50 medflies were trapped in the Boca Raton area of Palm Beach County last June. Quick response by state and federal officials resulted in that outbreak being declared eradicated within three months.

There is no news about the spread of “hot” psyllids or of citrus greening in Mexico, but it was announced that greening has been detected in Costa Rica. The announcement of four infected citrus trees in northern Costa Rica was made February 21. Officials speculate that the infections may have come from Nicaragua, where greening was detected last year. There was no information concerning psyllids, “hot” or otherwise, in the northern zone where the disease was detected.

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 IS IMPLIED.