MARCH, 2010      

VOL. 24, NO. 3                                                                             

IN THIS ISSUE:

www.TexasCitrusGreening.org
FLORIDA CROP LOSSES
TEXAS CROP
INTERCEPTIONS IN NORTH DAKOTA
CURRENT SITUATION
TCM MID-YEAR MEET

www.TexasCitrusGreening.org

The ACP/CG website that many of us have labored over for longer than we would care to remember is up at last, having gone online on February 15.  While still a work in progress, you can access the site at http://texascitrusgreening.org to find information on the psyllid and the citrus greening disease as they pertain to Texas, as well as links to various other websites that have information about the vector or the disease.

Because of some confusion about so many leaf chlorosis patterns in citrus, we have tried to depict as many of the chlorosis patterns that have causes other than citrus greening, as well as those that are unique to the disease.  The one thing that all growers should know is that the single most common symptom—and usually among the first to appear—of citrus greening, regardless of type, variety or age of tree, is the leaf blotchy mottle pattern. 

By definition, “mottle” is an irregular pattern of patches or spots of different colors, while “blotch” refers to irregularly shaped patches or discolored areas.  For our purposes, then, “blotchy mottle” refers to an irregular pattern of irregular blotches, with the colors being some degree of yellow and green.  Another thing to remember is that the yellowed blotches can and do cross lateral veins in the leaf (though they may not) but they do not cross the leaf midrib.

Florida Crop Losses

The Florida and National Agricultural Statistic Services have released data on the reduction in the Florida citrus crop estimates as the result of the early January period of freezing temperatures that hung on for over a week there.  Essentially, the early and mid-season orange estimate was lowered 4.0 percent to 66 million boxes due to smaller fruit size and increased droppage.  Valencias were lowered 5.0 percent to 63 million boxes, primarily because Valencia sizes have trended smaller than anticipated this season.

The Florida grapefruit estimate was reduced 4.0 percent to 18.8 million boxes, mainly due to slower overall fruit growth rates than expected.

Texas Crop

Texas crop estimates are unchanged from the January updates.  The question remains as to just how much loss Texas fruit may have suffered, and there is no easy answer.  Trying to compare eliminations to juice since January 13 may provide a clue, but even that is not certain. 

For example, weekly eliminations of early/mids to juice over all of the last five seasons was about the same as that since January 13 of this year, but eliminations since January 13 this season  are double that of the period before January 13.  In other words, eliminations of this crop before January 13 were only about half that of the 5-year average (more fruit went into the box or bag than in prior years), but returned to average after January 13.  The upsurge in weekly eliminations since January 13 suggests that increased fruit drop due to cold damage was occurring, so harvesters were moving greater volumes to juice to avert greater losses.

On the other hand, grapefruit does not appear to have been impacted.  Eliminations have increased by 1.8 times that of pre-January 13 levels, but that is the same increase as for the 5-year average.  Moreover, this season’s weekly eliminations both before and after January 13 are roughly 75 percent of that for the historical period.  In other words, the increase in eliminations since January 13 parallels that of prior seasons, indicating a normal increase in eliminations as opposed to an increase due to other factors (i.e, freeze damage).

On another note, sky-exposed Valencia oranges—those that were freeze damaged (drying out) in the upper quarter inch of the fruit—do not show much drying now, suggesting that Valencias are recovering.  This “healing” should continue.

Interceptions in North Dakota

In December and January, Customs and Border Protection at Pembina, ND, (near Grand Forks) intercepted and confiscated mandarins that travelers from Canada were carrying enroute to winter vacations in the Sun Belt.  Citrus black spot (fungal) and arrowhead scale were identified on the confiscated fruit.  While the exact destinations were not given, one can speculate that crossings in North Dakota are bound for Texas.

Current Situation

The amount of rain since Thanksgiving has surpassed any winter in my memory of the last 30 years—toting up about 10 inches where I have gauges.  Accompanying weather has been somewhat cool (I don’t have the departure from average for the period—it just seems to have been cooler than normal to me, though maybe I’m getting more sensitive to temperature as I mature).  In any case, here it is March first and even navels have not hit full bloom yet—they have been trying, but they just aren’t progressing with the rapidity of past seasons when they were usually peaked out by now. 

The flush is so strung out this season that if the next two weeks bring warm temperatures and plenty of sunshine, we may see a near-overlap in the bloom of navels, other oranges and grapefruit.  In other words, we may have a very concentrated period of flowering this month.

As grove conditions have allowed, growers have been busy the last couple of months with fertilization, herbicide applications, Temik applications, psyllid control sprays, hedging/topping, and harvesting.  About the only thing not being necessary is irrigation—at least in most groves.

Texas Citrus Mutual Mid-Year Meet

I don’t have the details of the program at this time, but TCM’s annual mid-year meeting is scheduled for March 25 at the TAMU-K Citrus Center, so mark your calendar for that date.  Details of the program will be announced in the on-line newsletter from the TPA.



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