BRUSH COUNTRY HORTICULTURE

Texas Agricultural Extension Service
The Texas A&M University System

DECEMBER, 1995 VOL. 6, NO. 12
IN THIS ISSUE:
CITRUS FRUIT DRYING OUT ----- There have been a large number of complaints from Orange, TX, to the Valley regarding mandarin citrus having colored early and having one or more sections that are totally dried out. The most common complaint involves tangerines. The culprit was the leaf-footed plant bug (a stink bug) that was feeding on the fruit in July, August and September, maybe even yet. Because mandarin fruit are so thin-skinned with virtually no albedo (the white part of the peel), feeding punctures by this insect usually penetrate into the juice segments, thereby causing them to dry out because of the hole in the segment membrane. Grapefruit represents the opposite extreme a usually thick albedo through which the insect rarely penetrates. Thus, damaged grapefruit will often show external gumming on the surface of the fruit and one can usually follow the browned feeding puncture down through the peel where it disappears in the albedo before reaching the juice segments. Often, a piece of leaf tissue will be stuck to the gum on the grapefruit surface. Oranges fall somewhere in the middle between grapefruit and mandarins, though navel oranges that are penetrated to the juice more commonly develop a decay, rot and drop off the tree, especially if the puncture is near the navel end of the fruit where the peel is usually very thin. Clientele may argue that they had no stink bugs on their trees, but the damage indicates otherwise. Julian W. Sauls Professor & Extension Horticulturist

BROWN CITRUS APHID IN FLORIDA ----- The waiting is over the brown citrus aphid has been detected in South Florida. The first find was in Davie, FL, on November 3; a second find a few miles away in Plantation was detected on November 10. Both detections were on dooryard trees both sites are in the Ft. Lauderdale area. Extensive surveys are underway in the area. The affected citrus trees have been treated with Lorsban followed by Admire. At this writing, it is unknown if infestation exists beyond the immediate area of the two finds. Julian W. Sauls Professor & Extension Horticulturist

IMPORTED FIRE ANT ----- Spot infestations of the imported fire ant have been identified in Cameron County over the last couple of years, and have been treated as they occurred. These infestations were thought to have come into the Valley in container nursery stock from other areas of the state. Recently, mounds of the imported fire ant have appeared in a local pecan orchard and other infestations have been reported in Hidalgo County. Once this pest becomes established in irrigated pastures and orchards, it will likely spread rather rapidly. The reason is that under conditions of flooding, whether caused by flood irrigation or heavy rains, the fire ants form a raft-like mass that floats on the water so they just float downstream until the water subsides (or they encounter high ground) and then form new colonies underground. The floating mass includes the young, eggs and the queen. Eradication does not appear to be a viable option. Treatment options with insecticides are limited. One treatment that will cause the ants to drown is spraying the floating rafts with detergent until they all sink however, we cannot determine if the soap treatment is legal in the eyes of the Environmental Protection Agency and we remember when EPA considered soap spraying of bees to be illegal. Julian W. Sauls Professor & Extension Horticulturist

WHAT HAPPENS TO PESTICIDES IN LAWN CLIPPINGS DURING COMPOSTING?--- A study by F.C. Michel, Jr. and others at Michigan State University (published in Applied and Environmental Microbiology 61:2566-2571, 1995) looked at the fate of 2,4-D, a commonly used lawn herbicide following composting of a leaf and grass mixture for 50 days. They found that almost 50% of the 2,4-D was degraded to carbon dioxide by microorganisms. Almost all of the remainder was either converted to humus or chemically bound to the organic matter. The herbicide-degrading microbes grew at a composting temperature of 140 F. and they occurred naturally in the composting material. Thus, the 2,4-D residue in lawn clippings will be inactivated by composting. Furthermore, it is likely that other pesticides (at least those with chemical properties similar to 2,4-D) will behave similarly during composting. Thomas Isakeit Assistant Professor & Extension Plant Pathologist

COMPOSTED YARD WASTE FOR NEMATODE CONTROL? ----- A study by R. McSorley and R. Gallaher at the University of Florida (published in Nematropica 25:53-60, 1995) looked at the effect of composted yard waste for management of the root knot nematode. The compost was either used as a mulch or incorporated into soil, into which was planted okra and squash, either as seeds or transplants. The compost treatments did not reduce nematode populations or galling on roots, but the yield of both crops was increased when transplants were used in combination with compost incorporated into soil. Rather than affecting nematodes directly, the compost was thought to have improved soil properties, resulting in more favorable growing conditions for the crops. In home gardens with serious nematode problems, nematodes could be managed through the use of transplants and incorporated compost, along with pre-plant soil treatments such as solarization and fallowing. Thomas Isakeit Assistant Professor & Extension Plant Pathologist

HORTICULTURE AND YOUR HEALTH ----- The current pecan crop is being enjoyed by Texans across the state, whether from yard trees, street trees, natives on river bottoms or commercial production. While pecan pie is a tradition through the holidays, there are more healthful uses of pecans than in pies and confections. The tendency to high consumption of olive oil, but reduced heart disease, in the Mediterranean region lead to the discovery of cholesterol-reducing benefits of certain fatty acids in olives. These same fatty acids are also present, in lesser amounts, in pecans. A study in 1993 concluded that substitution of about 60 percent of typical dietary fat with pecans or pecan oil reduced cholesterol levels about 10 percent after 8 weeks. The greater reduction was of the low density lipoprotein (LDL the "bad") cholesterol. The evidence keeps mounting that serious disease is critically linked to what one eats. To reduce heart disease problems, it would appear that consumers should eat more pecans, citrus fruits and olives to lower LDL cholesterol levels. Julian W. Sauls Professor & Extension Horticulturist

VALLEY IRRIGATION CONFERENCE --- The Lower Rio Grande Irrigation Conference is being presented by the Texas Agricultural Extension Service and the LRGV Irrigation District Managers' Association, with sponsorship by the Texas Water Development Board, the Texas Agricultural Irrigation Association and the Southmost Soil and Water Conservation District. This one-day conference and trade show will present current irrigation technologies and management practices and strategies to maximize production with limited water supplies and information on improving water-use efficiency. Three general sessions and four concurrent workshops will fill the day, offering critical information for all irrigation water use from pastures through row crops and orchards to golf course/turf irrigation. Registration is $15 per person if received by December 8, $20 thereafter and at the door. Checks are payable to Irrigation Conference and should be sent to the County Agricultural Extension office in either Edinburg, Rio Grande City, San Benito and Raymondville or can be mailed to Ms. Pamela Baker, Agricultural Engineering Department, Texas A&M University, College Station, TX 77843-2117. As you know, the prospects of a full allotment of irrigation water for 1996 are rather slim, which is expected to impact all agricultural use in the coming season. Given this scenario, it behooves all agricultural water users to be fully aware of the situation and to utilize all practical means available to survive this crisis with minimal adverse impact, if possible. I hope to see you there December 12, 7:30 to 4:30, McAllen Civic Center. Julian W. Sauls Professor & Extension Horticulturist

PIT SPITTING? ----- On the lighter side, a fellow by the name of Rick "Pellet Gun" Krause is the reigning North American Cherry Pit Spitting Champion who recently won the World Record Cherry Pit Spitting title in Germany. According to a report in American Fruit Grower (November, 1995), the North American competition requires fresh, chilled Montmorency tart cherries, while the competition in Germany allows canned, sweet cherries which have smooth pits and better aerodynamics. It is doubtful that pit spitting will achieve the prominence of watermelon seed pitting or cow chip tossing in Texas, but it's nice to see fellow growers enjoying the lighter side of fruit production. Julian W. Sauls Professor & Extension Horticulturist JULIAN W. SAULS, Ph.D. Professor & Extension Horticulturist 2401 East Highway 83 Weslaco TX 78596

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