WATER SITUATION
SHORT NOTES
CITRUS PEST UPDATE
IRRIGATION DISTRICTS AND
MUNICIPALITIES
CITRUS WEB
SEASON OPENS

WATER SITUATION-

While Tropical Storm Charley put a bunch of water in the reservoirs, Tropical Storm Frances soaked the Valley pretty well. At last count, the U.S. supply was boosted by more than 450,000 acre feet and stands a little above 35 percent of capacity. We still need substantial inflows, however-maybe it will happen over the next several months. It surely would be nice to start 1999 with a normal allocation.

Despite the drought, grain, corn and cotton in the Valley all apparently fared better than many observers expected. Most of those crops which were irrigated were able to complete the season before the shortage of water forced closure of several irrigation districts. Cane and citrus, however, experienced severe water stress in those dry districts-and the yields from those stressed fields will be down.

Overall, citrus still looks promising. Orchards showing severe wilt in August perked up nicely after the rains-obviously, a lot of leaf loss occurred. Production will be down in those orchards, but the industry as a whole should still surpass last year's production.

SHORT NOTES-

Asiatic citrus canker was identified in commercial orchards in Collier County, Florida, marking yet another find outside the urban Dade County area where the Division of Plant Industry, FDACS, has been battling the disease for about two years. So, canker is now being fought in Dade, Collier and Manatee Counties.

Mediterranean fruit fly is still a problem in Manatee County, (Florida) and in Lake County-and has been found in Highlands County.

While the imported fire ant is not yet a major problem in Texas citrus, Texas growers should know that Novartis has recently introduced Clinch® fire ant bait. Supposedly, broadcasting Clinch® will eliminate all mounds by virtue of the fact that the ants die slowly after ingestion of the bait, which means that foraging ants spread the bait through the colony. The material prevents egg laying by the queen after she eats the bait. It sounds too good to be true.

USDA and the University of California are testing lime-sulfur in heated water to reduce green mold and sour rot of citrus. Preliminary work with oranges and lemons showed substantially reduced disease, so work continues to check fruit quality and to test grapefruit and mandarins also.

While we do appreciate Tropical Storm Frances, she did put a damper on the Texas Produce Convention at South Padre Island, as some registrants and exhibitors either failed to show or pulled out early. Ironically, those who left early and headed toward the Houston area ran smack dab into what they were trying to avoid. There were some very good talks that stimulated both interest and discussion.

Citrus herbicides for pre-emergent weed control haven't changed much since the early 1980's. Mandate® was released in 1997 by Rohm and Haas. Another product with anticipated labeling in 2000 is azafenidin (Milestone®), developed by DuPont. Recent studies in Florida (Tucker and Delaney. 1997. Proc. Fl. State Hort. Soc. 110:51-54) showed comparable weed control with these two products. Mandate® has been widely tested in the Valley, while tests with Milestone® are still few.

And if you are one of those who continues to believe that Texas citrus uses a lot of water, the following situation should interest you. In the herbicide study reported above, a low water regime used 11.0 inches of irrigation plus 50.9 inches of rain in 1995, compared to 26.5 inches of irrigation in a ?moderate' water regime. Although rainfall dropped to 43.1 inches in 1996, microsprayer application rates were 11.9 and 23.9 inches, respectively, for the low and moderate regimes. This work was in the CONSERV project which has lots of water from Orlando waste water treatment. Two points, however, should be obvious-1) these are deep sands having very low water capacity, requiring much more frequent irrigation than we see here in the Valley and 2) the low level of irrigation (11 to 12 inches) is about what microsprayer-irrigated orchards have been using over the last several years in Texas.

CITRUS PEST UPDATE-
by Juan Anciso

Citrus rust mites continue to be at relatively low levels but most orchards will warrant a spray application for rust mites because of the September rains setting the stage for these infestations to develop during the harvest time when we don't expect them to be a problem and when they are sometimes overlooked. The armored scale complex, especially Florida red scale, continues to be causing problems and applications may be necessary this month to keep these populations down until some cool weather arrives and helps suppress them. Citrus leafminers are at low levels but are expected to increase due to the tremendous growth flushes. Sooty mold is being observed in several groves and much of this is due mostly to whiteflies and some mealybug but these infestations are quite varied and may require treatment.

Greasy spot and melanose have not been a problem but due to the rains, these diseases are infecting the new leaves which will be next year's mature leaves. The problem with these diseases is that one fungicide application is not going to solve the disease problem immediately and indefinitely. These diseases have to be managed in a manner that incorporates a strategy that looks at the health of the trees for the next year or so. This may mean a fall application of copper or Benlate® so next year's leaves are protected. It may also mean a spring or summer application of oil and copper but this depends much on past history of the grove and the weather conditions next year. Also, leaf litter is overlooked and, in serious situations, removal of that litter by flood irrigation or other means is necessary since that leaf litter is maintaining a high level of the disease (inoculum) and no amount of spray application is going to manage that disease situation. Location and rainfall amounts also impact disease severity which also should be factored in when deciding how stringent a disease prevention program is going to be needed to manage these diseases so they do not impact quality and production.

IRRIGATION DISTRICTS AND MUNICIPALITIES-

One of the problems in irrigation agriculture is the loss of water between the river and the farm, otherwise known as efficiency. For the most part, most irrigation districts do not have the necessary financial resources to put into system improvements that would increase their efficiency. On the other hand, some municipalities are short on water resources to meet expanding needs.

One suggestion under consideration is for municipalities to help finance improvements in the efficiencies of certain irrigation districts in exchange for the rights to the water saved as a result of the improvements.

According to a recent news article, the city of Roma is trying to purchase 4117.6 acre feet of water rights from Cameron County Irrigation District #2 (San Benito) for $2.88 million, which is $700 per acre foot of water. The irrigation district is looking to use the proceeds to fund improvements to the worst 20 percent of their system. That volume of water represents about 2.2 percent of the district's authorized water rights.

The argument within the district concerns selling of water rights versus selling of "saved" water. It will be interesting to see how this situation turns out.

CITRUS WEB-

The Texas citrus website is scheduled to go on-line by mid-October. The initial offering will be mostly the information that is published in the Texas Citrus Handbook, plus some important links to a few other sites. While some of the links will be to the industry, others will be to academics and a few will be to market information.

While the site may be on-line, it should be viewed as still under-construction, as there is an awful lot of information yet to be posted. Some it is being provided by industry, some by research and Extension and some by others. Because of that, we will post the information when and if we get it.

In addition, probably all of the contents of the Texas Citrus Handbook that are posted really need to be revised, which will also take time.

Access to the site is html://aggie-horticulture.tamu.edu

SEASON OPENS-

The rains in September delayed opening of the season as harvesting could not be carried out in wet orchards, but conditions had improved sufficiently by the end of the month that harvest crews started work. One precaution for harvesters is that of oil spotting or oleocellosis, especially in oranges. Because of high soil moisture and high relative humidity, the fruit is most turgid in early morning-and turgid fruit bruises very easily.

For best results, delay harvest until at least late morning (preferably even to the afternoon), use gloves and handle the fruit gently. Marrs oranges have a major problem will oil spotting at this time of year, but navels and grapefruit are also affected.

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