| Volume 6. No. 5 & 6 | May-June 1998 |
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Texas Vegetable Association Mid-Year Meeting
The Mid-year meeting for the Texas Vegetable Association will be held on Thursday June 11, 1998 beginning with registration at 7:30 a.m. at the Embassy Suites hotel in McAllen. The all day meeting will feature 15 speakers on various topics related to the vegetable industry and the two candidates for Texas Commissioner of Agriculture.
Participants in the all day meeting can earn up to 5.5 credits for Certified Crop Advisors and 2.25 credits for TDA CEU's.
Lunch will be provided for those who pre-register. For more information, contact M'Lys Lloyd, (956)584-1681.
1997-98 Onion Trial Results by L.M. Pike, C. Lander, R. Horn & L. Brandenberger
Results of the 1997-98 onion variety trials were recently completed and are available in table form in this newsletter.
During the past season, 27 different onion varieties were trialed in a commercial field in Fronton, Texas north of Rio Grande City. The trial was planted on October 17, 1997 with four lines on top of each raised soil bed which were spaced on 40 inch centers. Each variety was replicated four times in a randomized complete block design. Plots utilized the same fertility, furrow irrigation and pest management program that the adjacent commercial field used.
Plots were harvested on April 10, 1998 and data were recorded for four size classes and the percentage of split onions. Following harvest, laboratory tests were run for pyruvic acid and the percent of soluble solids for a 10 bulb sample from each variety in the trial.
The results of this trial represent only one trial during one growing season and do not provide definitive results for onion varietal performance. Be certain when selecting varieties for production to compare this data to similar trials run during different years and at different locations.
Texas ET Network and Web Site by Guy Fipps
The Texas ET Web Site is designed to assist commercial producers and others in making scientific-based irrigation decisions and has been in operation for over three years. Recently, we have made several changes to make it easier to use, and we also have a new web-site address which is: http://texaset.tamu.edu
The web-site lists daily weather summaries and PET data for over 15 locations in Texas. Information and interactive calculators are provided to allow users to determine the irrigation water needs (or ET) of plants and crops.
There are three methods that can be used by this web-site to determine the water needs of crops. The first method uses either one of the calculators at the web-site and by filling in the needed information can calculate the actual water needs for your crop, (Note: the interactive calculator is designed for experienced users, beginners should start with the first calculator). The second method tracks the daily and weekly PET values and uses this information subjectively to estimate water needs. The last method uses the average historic PET values to determine seasonal irrigation water needs and establishes monthly irrigation schedules.
This summer we plan on adding several new stations, begin reporting heat units and soil temperature, and continue to improve the user interface and support information. The following quick guide for the Texas ET Network and Web-site should help you get to the information you need.
| IF YOU WANT TO: | THEN CLICK ON: |
| Look up daily PET and weather summaries | On-Line Weather Stations |
| Determine water needs for agricultural crops | Water Requirements Calculator or Interactive Water Requirements Calculator |
| Determine location of nearest weather station | Map of On-line Weather Stations |
| Find a brief explanation of PET & ET | What are ET and PET? |
| Find detailed explanation of using PET for determining irrigation water needs of crops | Growers Guide |
Food Quality Protection Act & All Those Questions by Lynn Brandenberger and Stormy Sparks
If there is one thing that we are beginning to understand it is that without good information, FQPA will be implemented by EPA based on the default assumptions that every pesticide is used at maximum use rates, the maximum number of times, on every acre for every crop on the label, and is applied with the shortest pre-harvest interval. The default assumption is that the label represents actual use. In other words, risk will be determined for a particular pesticide or pesticide group based on the worst-case-scenario for all of the pesticides within the group. Our first line of defense is to provide them with realistic data to the contrary.
This brings up the need to collect realistic information on actual pesticide use by our agricultural industry. University research and extension people throughout the U.S. are turning to their producers and are asking questions about pesticide use that may not have been asked in the past. We need your help in documenting the actual use of agricultural chemicals in order to provide the most accurate data possible. Case in point, recently we were requested to survey carrots regarding pesticide usage for the National Agricultural Pesticide Impact Assessment Program (NAPIAP). Growers in South Texas and other carrot producing areas of the state were very cooperative and provided us with the necessary information to complete the survey. This willingness to share information and to put the effort into providing actual use data will hopefully go a long way towards a realistic interpretation of FQPA.
A word of caution in providing use data, be as accurate as possible. Overestimates would take up valuable room in a pesticide's "risk cup", while underestimates could end up as label restrictions that prevent needed uses.
Nematode Testing Can Save A Lot of Money by Tom Isakeit
Many vegetable growers in the Lower Rio Grande Valley routinely treat their fields for nematodes before planting, without having any evidence that they have a nematode problem. If nematodes are not present, such treatment is a waste of money. For a tiny fraction of what it costs to apply a nematicide to a field, a nematode test can be done that would give the grower the knowledge of whether such treatment is warranted.
A good time to analyze for nematodes is right after harvest and before the mulch is removed and the land is worked. At this time, nematode populations would be highest and samples could be obtained from the root area, which would give the best chance of accurate detection. If the soil is allowed to dry too much, populations might fall below detectable levels. Sampling from tilled soil following cropping will also underestimate populations.
Roots of the old crop should be examined for the galling symptoms of root knot nematode. This can pinpoint areas of the field that will likely have a future root knot nematode problem, even without doing a soil test. In the absence of visible root symptoms, soil samples will need to be taken, since the absence of root symptoms does not necessarily mean the absence of root knot nematode. Additionally, the reniform nematode can cause serious yield losses of melons without causing visible root symptoms.
The more samples taken, the better the indication of any problem. An individual sample can represent an area varying in size of 1 to 10 acres, but it should always represent a uniform part of the field. For example, portions of the field that have had different cropping histories or have differing soil types should be sampled separately. Areas with a previous history of nematode problems should be sampled more intensively. An individual sample should be composed of several sub-samples (10 or more). The use of a large number of sub-samples, taken from several places in the sampling area, will give a good representation of the nematode population. There are no fixed rules for how many samples or sub-samples to take, but some time must be invested in getting a good sample. One scoop of soil from one spot in the field is not a good sample.
Soil should be collected from the root zone of the harvested crop, 4 to 12 inches deep. An auger or soil-sampling tube should be used. Samples should not be taken from near the soil surface. The soil should be moist (friable), but not wet. The inclusion of fine plant roots in the sample is encouraged. Sub-samples should be thoroughly mixed and about one pint of the resulting composite of these sub-samples is removed and submitted as the sample.
The sample should be sealed in a plastic bag. It should not be allowed to dry out, nor should water be added to it. It should be kept cool; under refrigeration, if possible. However, it should not be frozen. The sample should be transported to the diagnostic lab as quickly as possible, preferably using an overnight delivery service.
Nematode analysis is done at the Plant Disease Diagnostic Clinic in College Station and is a fee-based service that costs $20 per sample. The test involves extracting living nematodes from soil and identifying and counting them using magnification. Since these nematodes are sensitive to drying and heat, proper sample handling, as previously described, is very important to ensure detection. The address of the lab is: Texas Plant Disease Diagnostic Laboratory, Department of Plant Pathology and Microbiology, Texas A&M University, Room 101, L.F. Peterson Building, College Station, TX 77843. Questions can be directed at Dr. Larry Barnes or Mr. Jerry Trampota at (409) 845-8033. A form for submitting nematode samples to the lab is included in this newsletter.
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| Cultivar | Seed Source | Color | Yield in 50 lb. bags per acre | Splits (%) | Pyruvic acid (µmol./g. Fwt.)* | Soluble solids (%)* | Cultivar | ||||
| Colossal | Jumbo | Medium | Pre-pack | Total | |||||||
| Daybreak | Shamrock | Yellow | 192 | 741 | 110 | 29 | 1072 | 0.1 | 4.0 | 7.6 | Daybreak |
| XPH 6786 | Asgrow | Yellow | 55 | 631 | 250 | 80 | 1016 | 0.0 | 3.3 | 6.5 | XPH 6786 |
| XPH 6825 | Asgrow | Yellow | 15 | 682 | 269 | 49 | 1015 | 0.0 | 4.0 | 6.9 | XPH 6825 |
| RCX 5761 | Rio Colorado | Yellow | 71 | 687 | 195 | 40 | 993 | 0.0 | 4.4 | 8.0 | RCX 5761 |
| RCX 5787 | Rio Colorado | Yellow | 66 | 641 | 216 | 43 | 965 | 0.1 | 4.1 | 7.8 | RCX 5787 |
| Chula Vista | Petoseed | Yellow | 43 | 582 | 266 | 61 | 952 | 0.1 | 3.5 | 7.0 | Chula Vista |
| Linda Vista | Petoseed | Yellow | 32 | 532 | 317 | 57 | 938 | 0.2 | 3.8 | 7.2 | Linda Vista |
| XPH 6794 | Asgrow | Yellow | 76 | 563 | 214 | 47 | 899 | 0.0 | 3.3 | 7.5 | XPH 6794 |
| RCX 3069 | Rio Colorado | Yellow | 14 | 417 | 348 | 94 | 873 | 0.1 | 4.4 | 7.0 | RCX 3069 |
| XPH 6787 | Asgrow | Yellow | 57 | 526 | 196 | 93 | 872 | 0.2 | 4.1 | 7.1 | XPH 6787 |
| 81069 | Texas A&M | Yellow | 94 | 503 | 220 | 45 | 861 | 1.1 | 4.4 | 7.3 | 81069 |
| Henry Special | Sunseeds | Yellow | 30 | 519 | 231 | 81 | 860 | 0.6 | 4.0 | 7.5 | Henry Special |
| Lexus | Petoseed | Yellow | 29 | 515 | 210 | 97 | 852 | 0.1 | 4.3 | 8.1 | Lexus |
| RCX 5797 | Rio Colorado | Yellow | 25 | 474 | 292 | 56 | 848 | 0.0 | 4.1 | 8.3 | RCX 5797 |
| PS 13589 | Petoseed | Yellow | 56 | 504 | 212 | 75 | 846 | 0.2 | 3.9 | 7.8 | PS 13589 |
| Sun Sweet | Sun Seeds | Yellow | 46 | 556 | 167 | 67 | 835 | 0.5 | 4.0 | 7.7 | Sun Sweet |
| 81070 | Texas A&M | Yellow | 12 | 388 | 334 | 82 | 817 | 0.1 | 4.1 | 8.0 | 81070 |
| 81043 | Texas A&M | Red | 28 | 414 | 293 | 79 | 814 | 0.2 | 4.9 | 8.4 | 81043 |
| 81079 | Texas A&M | Yellow | 36 | 457 | 240 | 73 | 805 | 0.0 | 4.7 | 7.6 | 81079 |
| Diamante | Sun Seeds | White | 38 | 453 | 240 | 65 | 795 | 0.5 | 4.6 | 9.1 | Diamante |
| 81014 | Texas A&M | White | 10 | 348 | 275 | 120 | 752 | 0.1 | 5.2 | 9.4 | 81014 |
| Eureka | Shamrock | White | 43 | 369 | 231 | 81 | 724 | 0.8 | 3.9 | 8.5 | Eureka |
| Lucero | Shamrock | White | 39 | 371 | 204 | 83 | 698 | 1.1 | 3.8 | 8.5 | Lucero |
| ACR 970N01 | Abbott & | Yellow | 96 | 355 | 147 | 68 | 666 | 2.5 | 4.5 | 8.0 | ACR 970N01 |
| 81036 | Texas A&M | Red | 4 | 128 | 265 | 143 | 541 | 0.2 | 4.1 | 8.1 | 81036 |
| 81018 | Texas A&M | White | 2 | 193 | 233 | 104 | 531 | 0.0 | 5.9 | 8.6 | 81018 |
| SSC 6094** | Shamrock | Yellow | 95 | 44 | 5 | 1 | 144 | 7.3 | 4.9 | 8.1 | SSC 6094** |
| LSD (0.05) | NA | NA | 47 | 128 | 87 | 45 | 120 | 1.4 | NA | NA | LSD (0.05) |
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Lynn Brandenberger/Editor
The information given herein is for educational purposes only. References to commercial products or trade names are made with the understanding that no discrimination is intended and no endorsement by the Cooperative Extension Service is implied.