Cooperative Extension Service 
                                                   ________________________________________________

Institute of Food and Agricultural Sciences

Hendry County Cooperative Extension Office
PO Box 68
Labelle, Florida 33975
863-674-4092

      Southwest Florida Vegetable Newsletter

July - August, 2002

Index:

Calendar

September 4-6          The 26th Annual Joint Tomato Committee and Florida Tomato
                                  Committee Meeting
                                  Ritz Carlton, Naples
                                  Contact Phyllis Gilreath at 941-722-4524

September 17          Vegetable Growers Meeting Whitefly Management
                                 UF/IFAS SFREC
                                 Immokalee.
                                 For more information call 863-647-4092

September 18-19     Pesticide Training Class
                                 Hendry County Extension Office
                                 LaBelle
                                 For more information call 863-674-4092.

September 24-25    Spanish Pesticide Class
                                Hendry County Extension Office
                                LaBelle
                                For more information call 863-674-4092

September 26        Vegetable Growers Meeting FMC Product Update
                               UF/IFAS SFREC
                               Immokalee
                               For more information call 863-674-4092

December 8-12     Cucurbitaceae 2002
                               Naples Beach Hotel and Golf Club
                               Naples
                               Contact Don Maynard 941-751-7636 x239 or dnma@mail.ifas.ufl.edu

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Note from Gene

Gene McAvoy 
Vegetable Extension Agent II 
Hendry County Extension Office 
PO Box 68 
LaBelle, Florida, 33975 
863-674-4092 

GMcAvoy@mail.ifas.ufl.edu
I hope that this note finds you all well.  It seems like this summer just flew by and here we are going into the 2002-2003 growing season.  I pray that it will be a good one and that we will be blessed with good weather and good markets too.
 The vegetable industry in southwest Florida has a long and rich tradition rooted in those hardy pioneers who came to this wild and remote country spurred by rumors of rich soil and abundant water and sunshine and motivated by dreams of a better life for their families.  Beginning with those early settlers who literally hacked out their dream for a brighter future from the wilderness, vegetable production has grown over the years with the assistance of advances in research and technology to become a multi-million dollar industry supporting thousands of individuals.

The past few seasons have been difficult ones for vegetable growers in southwest Florida. Recent years have been marked by a diversity of challenges, which has induced many growers to examine new strategies for survival and has left some struggling to just to stay afloat. As in the past, the industry’s ability to change and adapt to challenge will be the key to survival.

Just as recent years have bought unsettled times to the vegetable industry, IFAS has also come upon hard times with a succession of budgets cuts threatening it’s ability to provide the vegetable industry with solutions to problems and the cutting edge technologies that have time and time again allowed the industry to grow and prosper in the face of adversity.  In the same way that familiarity sometimes leads us to take our good friends and spouses for granted, the industry ‘s close relationship and dependence on the unbiased applied research conducted by IFAS scientists may have lead some to the belief that IFAS will always be there when needed.

Unfortunately, the fact is that IFAS needs your help. Over the past few budget sessions, drastic reductions in funding levels have cut to the bone.  These cuts have been disproportional, falling heavily on the University of Florida and threatening the university’s ability to continue to provide the support that growers have come to expect and depend upon.

Challenges will continue to confront vegetable producers and survival in this dynamic environment is possible only if Florida’s growers can remain competitive through technological advances based on sound research.  Now as IFAS is faced with the real possibility of staffing cuts and the closure of research centers, the vegetable industry needs to ask some hard questions.   Will my needs be met?  How will they be met?  Who will provide the unbiased research needed by the industry?  Will there be adequate resources to turn out the trained people needed to support agriculture?

What can you do to help?  Write or talk with your elected representatives – State Senators and Legislators.  Educate them on the economic contribution of your industry to Florida’s economy.  Explain to them how dependent your industry is on the research performed at IFAS to solve the problems that affect the industry.  Join with industry groups like the Florida Tomato Committee, Farm Bureau and Florida Fruit and Vegetable Association and others to rally support for IFAS and help ensure that your research needs are met in the future.

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Gulf Coast 
Research and Education Center Tomato Variety Evaluation Spring 2002
In 2000-2001, 43,800 acres of tomatoes were harvested in Florida, yielding 63.7 million 25-Pound cartons worth over $588 million.  Tomatoes accounted for over 34% of the total value for all vegetables grown in Florida during 2000-2001, making it the most important vegetable Produced in the state.  The Palmetto-Ruskin area (west-central Florida) accounted for over 36% of the state’s total fresh market tomato production in 1999-2000.

A tomato variety trial was conducted in spring 2002 at the Gulf Coast Research and Education Center-Bradenton located in west-central Florida to evaluate fresh market tomato varieties and breeding lines.  The replicated yield trial included 27 entries.

Seeds were sown on 15-16 February into planter flats containing a commercial mix.  Transplants were fertilized periodically with a liquid 20-20-20 (N-P205K20) to sustain growth during Production.  Plants were conditioned before transplanting by limiting water and nutrients in the final phase of production.

The land was prepared in early February.  Beds were formed and fumigated with methyl bromide:chloropicrin, 67:33 at 350 lb/treated acre.  Banded fertilizer was applied in shallow grooves on the bed shoulders at to provide 282-0-392 lbs N-P205-K20/A after the beds were pressed and before the white polyethylene mulch was applied.  The final beds were 32-in. wide and 8-in. high, and were spaced on 5-ft centers with six beds between seepage Irrigation/drainage ditches, which were on 41-ft centers.

Transplants were set in the field on 4 March and spaced 24 in. apart in single rows down the center of each bed.  Transplants were immediately drenched with water containing 16 fl. oz/acre of imidacloprid for silverleaf whitefly control.  Four replications of 10 plants per entry were arranged in a randomized complete block design. However, data is reported for only two replications because of poor growth in the other two replications.  Plants were lightly pruned, staked, and tied.

Plants were scouted for pests throughout the season.  A preventative spray program was followed for management of plant pathogens.

Fruit were harvested three times at or beyond the mature-green stage on 7 May and 20-21 May and 3-4 June.  Tomatoes were graded as cull or marketable by U.S. standards for grades and marketable fruit were sized by machine.  Marketable fruits of each size were counted and weighed.

Seasonal yields from three harvests ranged from 1634 cartons/acre for HMX 0800 to 2967 cartons/acre for Fla. 7973.  Twenty other entries had yields similar to those of Fla. 7973.  All but one entry produced yields greater than the state average yield for spring 2000 of 1693 cartons/acre.

Yields of extra-large fruit varied from 1256 cartons/acre for ACX 12A to 2543 cartons/acre for Fla. 7926.  Yields of Fla. 7926 extra large fruit were not different from those of 17 other entries.  Large fruit yields ranged from 169 cartons/acre for RFT 0252 to 707 cartons/acre for ‘Lucky 13’.  Cull fruit for the entire season varied from 12% by weight for RFT 0252 and ‘Florida 91’ to 30% for ACX 12A.  Blossom-end rot, rough shoulders, and small fruit were the principal defects during the latter part of the season.  Average fruit weight was from 5.5 oz for ‘Lucky 13’ to 7.6 oz for RFT 0417.  TYLC- infected plants ranged from 0 for several entries to 60% for HMX 0800.  Over 80% of the entries had at least one infected plant.

Yields in the spring 2002 season were similar to those in recent spring seasons at this location. Exceptional experimental hybrid performers in spring 2002 were Fla. 7973, Fla. 7926, HMX 1803, XTM 0227, Fla. 7810, HA-3060, and TY00-568.

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Table 1.  Seed source, total marketable yields, and average marketable fruit weight, for fresh market tomato entries in spring 2002.  (Harvest Dates:  7, 20-21 May and 3-4 June 2002.)
   
 Total Harvest
Total  X-Large  Large Medium Avg Fruit
Entry  Source 
----------------(cartons/A)1-------------
 Wt (oz)
Fla. 7973  GCREC-UF 2967 a2 2467 ab 409 c-e 91 bc 6.7 b-e
Fla. 7926  GCREC-UF  2799 ab  2543 a  208 d-f  48 bc  7.2 a-c
HMX 1803 Harris Moran 2787 a-c 2429 ab 281 d-f 78 bc 6.9 b-d
BHN 591 BHN Research 2749 a-c 2380 ab 318 c-f 51 bc 6.9 b-d
BHN 586  BHN Research 2717 a-c 2358 ab 311 c-f 49 bc 6.6 c-e
-----------------------------------------------------------------------------------------------------------------------------
XTM 0227 Sakata 2666 a-c 2351 ab 267 d-f 47 bc 7.3 ab
Fla. 7810 GCREC-UF 2652 a-c 1903 bc 629 ab 120 b 6.1 ef
HA-3060 Hazera 2652 a-c 2255 ab 327 c-f 71 bc 6.4 d-f
Florida 47 Seminis 2626 a-c 2209 ab 363 c-f 53 bc 6.7 b-e
TY00-568 Hazera 2615 a-c 2195 ab 358 c-f 62 bc 6.7 b-e
HA-3650 Hazera 2602 a-c 2325 ab 244 d-f 33 bc 7.0 a-d
PX150535 Seminis 2596 a-c 2322 ab 237 d-f 37 bc 7.4 ab
RFT 0417 Syngenta 2593 a-c 2385 ab 182 f 25 bc 7.6 a
ASX 911 Agrisales 2521 a-c 2157 ab 313 c-f 51 bc 6.8 b-e
RFT 0247 Syngenta 2511 a-c 2224 ab 268 d-f 18 bc 7.1 a-d
EX1405037 Seminis 2500 a-c 2257 ab 214 d-f 29 bc 7.3 ab
RFT 0252 Syngenta 2492 a-c 2310 ab 169 f 12 c 7.1 a-d
SVR 1432427 Seminis 2473 a-c 2134 ab 294 c-f 45 bc 7.0 a-d
Agriset 761 Agrisales 2452 a-d 1926 bc 415 cd 111 bc 6.6 c-e
Florida 91 Seminis 2410 a-d 2141 ab 222 d-f 47 bc 6.9 a-d
Lucky 13 Agrisales 2391 a-d 1390 cd 707 a 294 a 5.5 g
HA-3636 Hazera 2275 b-e 1904 bc 306 c-f 65 bc 6.8 b-e
Fla. 7964 GCREC-UF 2260 b-e 1934 bc 267 d-f 58 bc 6.7 b-e
Sanibel Seminis 2138 c-f 1904 bc 202 ef 31 bc 6.8 b-e
ACX12A Abbott & Cobb 1837 d-f 1256 d 494 bc 86 bc 5.9 fg
RFT 6153 Agrisales 1752 ef 1505 cd 208 d-f 39 bc 6.9 b-d
HMX 0800 Harris Moran 1634 f 1370 cd 228 d-f 35 bc 6.8 b-d
1Carton = 25 lbs.  Acre = 8712 lbf.  Grading belt hole sizes: X-Large = no belt, greater than 2.75”; Large = 2.75”-2.51”; Medium = 2.5”-2.26”; and Cull < 2.25”. 2Mean separation in columns by Duncan’s multiple range test, 5% level.

(Maynard - Vegetarian 02-08)

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Tomato Varieties for Florida
Variety selections, often made several months before planting, are one of the most important management decisions made by the grower. Failure to select the most suitable variety or varieties may lead to loss of yield or market acceptability.

The following characteristics should be considered in selection of tomato varieties for use in Florida.

Yield - The variety selected should have the potential to produce crops at least equivalent to varieties already grown. The average yield in Florida is currently about 1400 25-pound cartons per acre. The potential yield of varieties in use should be much higher than average.

Disease Resistance - Varieties selected for use in Florida must have resistance to Fusarium wilt, race 1, race 2 and in some areas race 3 ; Verticillium wilt (race 1); gray leaf spot; and some tolerance to bacterial soft rot. Available resistance to other diseases may be important in certain situations, such as Tomato Spotted Wilt resistance in northwest Florida.

Horticultural Quality - Plant habit, stem type and fruit size, shape, color, smoothness and resistance to defects should all be considered in variety selection.

Adaptability - Successful tomato varieties must perform well under the range of environmental conditions usually encountered in the district or on the individual farm.

Market Acceptability - The tomato produced must have characteristics acceptable to the packer, shipper, wholesaler, retailer and consumer. Included among these qualities are pack out, fruit shape, ripening ability, firmness, and flavor.

Current Variety Situation -  Many tomato varieties are grown commercially in Florida, but only a few represent most of the acreage. In years past we have been able to give a breakdown of which varieties are used and predominantly where they were being used but this information is no longer available through the USDA Crop Reporting Service.

Tomato Variety Trial Results -  Summary results listing the five highest yielding and the five largest fruited varieties from trials conducted at the University of Florida’s Gulf Coast Research and Education Center, Bradenton and North Florida Research and Education Center, Quincy for the Spring 2001 season.  High total yields and large fruit size were produced by BHN 543 at both Bradenton and Quincy.  Large fruit size was produced by PS 150535 at both locations. The same entries were not included at both locations.

Summary of results listing the five highest yielding and five largest fruited entries from trials at the University of Florida’s Indian River Research and Education Center, Ft. Pierce; and the North Florida Research and Education Center, Quincy for the fall 2001 season. High total yields and large fruit size were produced by Fla. 7943 at Bradenton; Fla. 7943, Florida 91 and Sanibel at Fort Pierce; and by BHN 189 and BHN 537 at Quincy. Fla. 7943, Sanibel and Solar Set produced high yields at two of three locations and Florida 91 and RFT 0418 produced large fruit at two of three locations. Not all entries were included at both locations.

Tomato Varieties for Commercial Production-  The varieties listed have performed well in University of Florida trials conducted in various locations in recent years.

Large Fruited Varieties

Agriset 761 - Midseason, determinate, jointed hybrid. Fruit are deep globe and green shouldered. Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), Alternaria stem canker, gray leaf spot. (Agrisales).

BHN-444 - Early-midseason maturity. Fruit are globe shape but tend to slightly elongate, and green shouldered. Not for fall planting.  Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), gray leaf spot, and Tomato Spotted Wilt. For Trial. (BHN).

Florida 47 - A late midseason, determinate, jointed hybrid. Uniform green, globe-shaped fruit.  Resistant: Fusarium wilt (race 1 and 2), Verticillium wilt (race 1), Alternaria stem canker, and gray leaf spot. (Seminis).

Florida 91 -  Uniform green fruit borne on jointed pedicels. Determinate plant. Good fruit setting ability under high temperatures.  Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), Alternaria stem canker, and gray leaf spot. (Seminis).

Floralina - A midseason, determinate, jointed hybrid. Uniform, green shoulder, flattened, globe-shaped fruit. Recommended for production on land infested with Fusarium wilt, Race 3. Resistant: Fusarium wilt (race 1, 2, and 3), Verticillium wilt (race 1), gray leaf spot. (Seminis).

PS 150535 - Midseason, determinate, jointed hybrid. Fruit are oblate and uniform-green shouldered. Recommended for situations where tomato yellow leaf curl virus is expected to be a problem. Resistant: TYLCV, Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), Alternaria stem canker, gray leaf spot. (Seminis).

 Solar Set -  An early, green-shouldered, jointed hybrid. Determinate. Fruit set under high temperatures (92oF day/72o night) is superior to most other commercial varieties. Resistant: Fusarium wilt (race 1 and 2), Verticillium wilt (race 1), Alternaria stem canker, and gray leaf spot. (Seminis).

Sanibel - A late-midseason, jointless, determinate hybrid. Deep oblate shape fruit with a green shoulder. Tolerant/resistant:  Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), Alternaria stem canker, root-knot nematode, and gray leaf spot.  (Seminis).

Solimar -  A midseason hybrid producing globe-shaped, green shouldered fruit. Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), Alternaria stem canker, gray leaf spot. (Seminis).

 Sunbeam - Early midseason, deep-globe shaped uniform green fruit are produced on determinate vines. Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and race 2), gray leaf spot, Alternaria stem canker. (Seminis).

Plum Type Varieties

Marina - Medium to large vined determinate hybrid. Rectangular, blocky, fruit may be harvested mature green or red. Resistant:  Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), Alternaria stem canker, root-knot nematodes, gray leaf spot, and bacterial speck. (Sakata).

Plum Dandy -  Medium to large determinate plants. Rectangular, blocky, defect-free fruit for fresh-market production. When grown in hot, wet conditions, it does not set fruit well and is susceptible to bacterial spot. For winter and spring production in Florida.  Resistant: Verticillium wilt, Fusarium wilt (race 1), early blight, and rain checking. (Harris Moran).

Spectrum 882 - Blocky, uniform-green shoulder fruit are produced on medium-large determinate plants. Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), root-knot nematode, bacterial speck (race 0), Alternaria stem canker, and gray leaf spot.  (Seminis).

Supra - Determinate hybrid rectangular, blocky, shaped fruit with uniform green shoulder. Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1 and 2), root-knot nematodes, and bacterial speck. (Syngenta).

Veronica - Tall determinate hybrid. Smooth plum type fruit are uniform ripening. Good performance in all production seasons.  Resistant: Verticillium wilt. (Sakata).

Cherry Type Varieties

Mountain Belle - Vigorous, determinate type plants. Fruit are round to slightly ovate with uniform green shoulders borne on jointless pedicels. Resistant: Fusarium wilt (race 2), Verticillium wilt (race 1). For trial. (Syngenta).

Cherry Grande -  Large, globe-shaped, cherry-type fruit are produced on medium-size determinate plants. Resistant: Verticillium wilt (race 1), Fusarium wilt (race 1), Alternaria stem blight, and gray leaf spot. (Seminis).

Reference - This information was gathered from results of tomato variety trials conducted during 2001 at locations specified in each table.  Tomato variety evaluations were conducted in 2000 by the following University of Florida faculty:
 H. H. Bryan Tropical Research & Education Center - Homestead
 D. N. Maynard Gulf Coast Research & Education Center - Bradenton
 S. M. Olson North Florida Research & Education Center - Quincy
 P. J. Stoffella Indian River Research & Education Center - Fort Pierce

Vegetarian August 2002
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Methyl Bromide Alert
The deadline to apply for a methyl bromide critical use exemption is September 9, 2002. The final federal rule implements reductions in the production and consumption of methyl bromide for 2001 and beyond, as follows.

Obviously, the big problem is the definition of "critical." Methyl bromide is an expensive and dangerous material, so people do not use it unless the use is very important. Naturally, nearly every methyl bromide user will consider their needs to be critical.  Unfortunately, the existing regulations do not clear up the definition.

The Montreal Protocol (an international agreement to protect the ozone layer) includes these rules for critical uses of methyl bromide.  “(a) That a use of methyl bromide should qualify as 'critical' only if . . .(ii) There are no technically and economically feasible alternatives or substitutes available to the user that are acceptable from the standpoint of environment and health and are suitable to the crops and circumstances of the nomination.”  Keep in mind that these are the international rules, so countries as well as grower groups are debating the word “critical.”

Originally, the Clean Air Act (a US law) did not allow any exemptions for the use of methyl bromide. The Act has been amended as follows. To the extent consistent with the Montreal Protocol, the Administrator, after notice and opportunity for public comment, and after consultation with other departments or institutions of the Federal Government having regulatory authority related to methyl bromide, including the Secretary of Agriculture, may exempt the production, importation, and consumption of methyl bromide for critical uses. In a nutshell, any U.S. exemption must be permitted under the Montreal Protocol.

There are two basic steps to obtaining a critical use exemption. First, convince the EPA of the critical use. Secondly, convince the international committees established by the Montreal Protocol (e.g., the Methyl Bromide Technical Options Committee and the Technical and Economic Assessment Panel). If you successfully complete those two simple steps, you have a critical use exemption good for one year (possible multiple years with an annual review.

In addition to basic information (crop, pest, location, etc.), the exemption process requires a great deal of information about alternatives to methyl bromide. The applicant must describe research into alternatives and explain why the current alternatives are not suitable. Plans to develop and commercialize substitutes for methyl bromide are required. Finally, the applicant has to include a plan that will facilitate the substitution of other materials/techniques for methyl bromide.  Post-harvest and structural uses must submit a similar application, but many quarantine and pre-shipment uses of methyl bromide are exempt from the phase-out.  If you are interested in more information on a critical use exemption for methyl bromide, visit this web site http://www.epa.gov/spdpublc/mbr/cueqa.html

Note:  FFVA and the Florida Tomato Committee have submitted critical use exemptions on behalf of Florida growers.

The Georgia Pest Management Newsletter
July 2002
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Tensiometers for Soil Moisture Measurement and Irrigation Scheduling 
Tensiometers are instruments used to measure the energy status (or potential) of soil water. This measurement is useful because it is directly related to the ability of plants to extract water from soil.  Tensiometers are used for irrigation scheduling because they provide direct measurements of soil moisture status and they are easily managed.

Tensiometer Components

A tensiometer consists of a porous ceramic cup, connected through a rigid body tube to a vacuum gauge, with all components filled with water.  The vacuum gauge can be equipped with a magnetic switch for automatic irrigation control.

Tensiometers are placed in the field with the ceramic cup firmly in contact with the soil in the plant root zone. The ceramic cup is porous so that water can move through it to equilibrate with the soil water. A partial vacuum is created as water moves from the tensiometer. The vacuum causes a reading on the vacuum gauge that is a direct indication of the attractive forces between the water and soil particles. This reading is a measure of the energy needed to be exerted by the plant to extract water from the soil.

Because the porous ceramic cup is permeable to both water and dissolved salts, tensiometers do not record the water potential due to dissolved salts (osmotic potential).  If soils are saline, or if poor quality irrigation water is being used, the osmotic potential will be a large portion of the total potential. In those cases, osmotic potential should also be measured using soil salinity sensors.

As the soil dries, water potential decreases (tension increases) and the tensiometer vacuum gauge reading increases. Conversely, an increase in soil water content (from irrigation or rainfall) decreases tension and lowers the vacuum gauge reading. In this way, a tensiometer continuously records fluctuations in soil water potential under field  conditions.

Rapid and accurate tensiometer response occurs only if air does not enter the water column. Air expands and contracts with changes in pressure and temperature, thus causing inaccurate tensiometer readings. Even if instruments do not leak, dissolved air enters with water flow through the ceramic cup during normal operation of the instrument. When a significant amount of air enters the instrument, it must be expelled and the tensiometer refilled with water before it will operate reliably again.

Units of Measurement

The tensiometer measures water potential or tension. Water potential is commonly measured in units of bars (and centibars in the English system of measurement) or kilopascals (in metric units). One bar is approximately equal to one atmosphere (14.7 lb/in 2 ) of pressure. One centibar is equal to one kilopascal.

A water potential reading of 0 indicates that the soil is saturated, and plant roots may suffer from lack of oxygen. As the soil dries, water becomes less available and the water potential becomes more negative. The negative sign is usually omitted for convenience when soil water potentials are measured with tensiometers. At least one company manufactures a “Florida” tensiometer with a range of 0-40 cb. The expanded scale in this range is ideal for irrigation scheduling in typical Florida sandy soils.

Range of Operation

Because of the vaporization of water at low pressure, the range of operation of a tensiometer is limited to 0 to about 85 cb. Above 85 cb the column of water in the plexiglass tube will form water vapor bubbles (cavitate), and the instrument will cease to function. This range represents only a fraction of the water tension range that is normally      considered to be available for plant growth. Many plants can survive to a water tension of 15 bars. However, plant growth and productivity cease well before this point. In sandy soils, tensiometers measure the entire range of soil water tension of interest for irrigation. Thus, the tensiometer is an excellent instrument for irrigation management in Florida.

Research has shown that to optimize production, irrigation should be scheduled when soil water tension reaches 10-20 cb in sandy soils. The exact values to be used depend on soil hydraulic properties, crop susceptibility, and production objectives. These water tensions are well within the tensiometer range of application.

Site Selection

Tensiometers measure soil water tension in the soil immediately surrounding the ceramic cup. Therefore, the ceramic cup must be placed in the active root zone of the crop for which irrigations are being scheduled. Depending upon crop type, two or more tensiometers may be required at a measurement site.

Because of differences in soil and plant characteristics, several measurement sites may be required to adequately assess the water status of large areas. For valuable or sensitive crops, more tensiometers should be used. For uniform soil types fewer tensiometers may be adequate.

The sites selected for installation should be representative of the surrounding field conditions. Isolated low, wet areas or high, dry areas should be avoided. Tensiometers should be placed within the plant canopy in positions where they will receive typical amounts of rainfall and irrigation. Placement of tensiometers with depth is critical. For shallow-rooted (less than 1 ft) crops such as some vegetables, only one tensiometer may be required with depth. It should be centered in the crop root zone, but at least 4-6 inches below the surface.

For deeper-rooted vegetable crops, two tensiometers should be used at each measurement site. The shallower one should be placed in the zone of maximum root concentration. This is normally at 6 inches or about one-third of the active rooting depth. The second unit is typically installed at a 12-inch depth.

When multiple instruments are used, most irrigations will be scheduled to replenish the upper part of the root zone monitored with the shallow instrument. The deeper instrument will indicate when less frequent larger irrigations are needed to replenish the entire root zone.

Installation

Proper installation requires that the instruments be in good hydraulic contact with the surrounding soil so that water can move into and away from them as efficiently as possible.  Before field installation, each tensiometer should be tested to verify that it is operating properly.

Tensiometers are installed in previously cored holes in the field. In sandy soils, the access holes can be cored by hand, while on heavier soils it may be necessary to use a hammer to aid the installation. The tensiometer is pushed into the access hole to the proper depth with the vacuum gauge located 2-3 inches above the soil surface. The soil around the tensiometer should be tamped at the surface to seal the instrument from air contact with the ceramic cup and to prevent surface water from running down around the tube. It is critical, regardless of the installation method used that the ceramic cup be in intimate contact with soil in order for the tensiometer to function properly.

The tensiometer should not be driven into place with a hammer or other object. Although adequate for normal use, the mechanical strength of the ceramic cup is not adequate to allow it to be hammered into place.

After installation, several hours may be required before equilibrium is reached and the tensiometer reads the correct soil water potential value. The correct reading will be reached more quickly in moist soils than in dry soils. After this initial equilibrium period, the tensiometer will accurately indicate the soil water tension, and it will closely follow changes in tension as they occur in the soil.

Tensiometers are delicate instruments and should be handled carefully and protected from impact by equipment or animals in the field.
Field Service

To operate properly, tensiometers must be serviced in the field periodically. This is because with normal use, air is extracted from water under tension. Air becomes trapped within the tensiometer and reduces response time progressively until the instrument fails to operate.

If the soil in which the tensiometer has been installed is moist, soil tensions will be low and very little air will accumulate. If, however, the tensiometer is installed in drier soils, with water potentials in the range of 40 to 60 cb, air will accumulate more quickly.

The body tube should be inspected for accumulated air each time the tensiometer is read. If over 1/4 inch of air has accumulated beneath the service cap, the cap should be  removed and the tube refilled with water.

In wet soils, the tensiometer will probably need to be serviced approximately every 2 weeks. In dry soils, servicing may need to be more frequent, perhaps as often as every time the tensiometer data is collected.

Irrigation Scheduling

Tensiometer measurements are useful in deciding when to irrigate because they give a continuous indication of soil water status, but they do not indicate how much water should be applied. The decision to irrigate is made when the average tensiometer reading exceeds a given critical value. To optimize production the critical value is normally in      the range of 10 to 20 cb for typical Florida sandy soils. The critical values are different for specific soil types, crops and stage of crop growth. At critical stages of crop growth, lower values are used, resulting in irrigations being scheduled more frequently. The critical values are also functions of economic considerations, with higher values set if the irrigated commodity price drops or if the cost of irrigation increases.

A tensiometer indicates only when irrigation should be scheduled, and not how much water should be applied. To determine the amount of water to be applied, a moisture characteristic curve specific for the irrigated soil must be used. The depth of irrigation water to be applied should be adequate to restore only the root zone to field capacity.  Excessive water will be lost to deep percolation below the crop root zone, carrying nutrients with it.

Tensiometer Service, Testing and Calibration

The tensiometer is a simple instrument that will work well if it is properly installed and in good condition. The instrument is in good repair if:

New instruments are normally in good repair. However, with time and usage, mechanical vacuum gauges may begin to fail, the ceramic cups may begin to plug, or air leaks may develop. Tensiometers should be periodically tested to insure that they are working properly, and that soil tensions are accurately read. At a minimum, tensiometers should be tested before each crop season for short-season crops. They should also be tested whenever their readings appear to be unusual, such as if the gauge remains on zero even though the soil dries as a crop uses water.

Servicing a Tensiometer

Servicing a tensiometer means preparing it for field operation or testing. This requires cleaning it if necessary, then filling it with fluid and expelling any entrapped air.

First wash the instrument to remove dirt, algae, bacterial slime and other foreign debris from both the inside and outside of the ceramic cup and tensiometer tube. This can be done with plain water and a brush. Use a small diameter bottlebrush to clean inside the tube and cup. Use household detergent to clean the instrument thoroughly.

If the instrument, especially the ceramic cup, is slimy this is probably the result of bacterial growth in the soil and water. Wash the ceramic cup and tube in a chlorine solution, using about 1/4 cup of household bleach (5.25% sodium hypochlorite solution) in a gallon of water. Allow the ceramic cup to soak in this solution overnight to be sure that all the bacteria are killed. Then rinse the instrument with water.

Fill the instrument with clean water or water with a mild biocide to help prevent organic growths in the tensiometer fluid. Most tensiometer manufacturers sell a fluid additive that is both a biocide and coloring agent that allows the tensiometer fluid to be easily seen. It is not mandatory that fluid additives be used, however additives will reduce the maintenance needed to keep the instruments clean and working properly.

Allow the ceramic cups to soak in water or tensiometer fluid for several hours or overnight to be sure that the ceramic is thoroughly saturated. Then fill the instrument with tensiometer fluid.

Remove excess air from the instrument using a hand held vacuum test pump available from the tensiometer manufacturer.  The vacuum test pump has a neoprene suction cup or stopper that allows it to replace the tensiometer cap. Then as the pump is operated, air is extracted from the ceramic cup, tube, and vacuum gauge and pulled to the top of the tube. Pump the tensiometer several times, refilling the tube with fluid each time if necessary until no further air is removed. Then remove the vacuum pump and refill the tube to the top with tensiometer fluid. The instrument is now ready to be tested for leaks or capped for use.

Testing a Tensiometer

To determine whether a tensiometer is working properly, three tests need to be conducted: 1) test for air leaks, 2) test that the mechanical vacuum gauge works, and 3) test that water can flow through the ceramic cup.

Test for large air leaks using the hand-held vacuum test pump. After the tensiometer has been cleaned and serviced, fill it completely full of fluid, then use the vacuum pump to make this test. Operate the vacuum pump to create a vacuum in the instrument.  A steady stream of air bubbles will indicate a large air leak.

When large air leaks occur, they are often around fittings or gaskets.  These can often be repaired using thread sealant or replacing o-rings. Large air leaks sometimes occur where the ceramic cup is cemented onto the plexiglass tube. These can often be repaired with a waterproof epoxy, however, all components need to be thoroughly dry before applying epoxy.

If no large air leaks occur, the mechanical vacuum gauge can be tested by comparing its reading with the test gauge on the vacuum test pump. Always buy a test pump with a test gauge installed. Then when the vacuum pump is used, the tensiometer gauge should read the same values as the test gauge. This is a quick and easy test that the tensiometer vacuum gauge is working and that its readings are approximately correct.  If the instrument gauge does not work, or if it is not accurate, most commonly used gauges must be discarded and replaced with a new gauge.

The final instrument test is a test for leaks and proper operation of the ceramic cup with the tensiometer sealed and ready for field installation. After the extraction of air and test of the vacuum gauge as described above, refill the tensiometer to the top and seal it with the tensiometer cap. Then place or hang the instrument in the atmosphere where water can evaporate from the ceramic cup to simulate soil drying. Because the instrument is sealed, as evaporation occurs the vacuum gauge reading should slowly increase (depending on the rate of drying) throughout the tensiometer range. This process may take an hour or more during which time the tensiometer fluid can be observed for streams of small air bubbles, which indicate small leaks in the instrument. Such leaks must be found and repaired because if they are not, the instrument will require frequent refilling in the field and the gauge reading will lag the true soil reading.

While the above slow-leak test is being conducted, a test of the ceramic cup flow properties is being conducted at the same time. If the ceramic cup pores are plugged, water will not flow through the ceramic and the instrument will not respond or will respond only very slowly to drying by the atmosphere. This will indicate a need for the ceramic to be cleaned more thoroughly before the instrument will work in the field. Because of the small pore sizes in the ceramic, they can readily be plugged by oil, grease, or other contaminants. Never use oil or grease on or around these instruments where the ceramics might become contaminated.

Tensiometer Calibration

Because tensiometers commonly use mechanical vacuum gauges, these instruments can become inaccurate or fail with time. Calibration is periodically required when tensiometers are used to control irrigation scheduling, especially for crops that are very sensitive to water stress. Two calibrations can be performed: 1) the vacuum test gauge quick calibration, and 2) the vacuum chamber detailed calibration.

Vacuum Test Gauge Quick Calibration

The vacuum test gauge calibration was previously described under tensiometer testing.

This is a quick test made by comparing the tensiometer gauge with the vacuum test gauge. The accuracy of this calibration depends on maintaining and using an accurate test gauge. If the tensiometer vacuum test pump used is equipped with a check valve to sustain the vacuum in the tensiometer tube, and a small bleed valve to slowly release the vacuum as desired, then the test instrument can easily be used to compare the gauges at several vacuum levels. First, operate the test pump to create a high level of vacuum in the tensiometer and read both gauges when they have equilibrated. Then operate the bleed valve to gradually reduce the vacuum level, stopping at each new level to read and record both vacuum gauges.

This procedure allows a quick test of a tensiometer gauge to be made throughout its range of operation. It offers the advantage that an instrument's calibration can quickly be checked in the field, using only a small, easily portable vacuum pump and test gauge.

Summary

Tensiometers are useful instruments for irrigation scheduling under field conditions, however, they require servicing, testing and calibration to insure that they are working properly. A tensiometer is a fairly simple instrument that will work well if it is properly installed and in good repair. The instrument is in good repair if:

All of the calibrations performed are independent of soil type, thus no field calibration is required. All calibrations can be done in the convenience and comfort of the shop or laboratory.
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Remember When
Stroll with me.... Close your eyes.... and go back... before the Internet... before bombings, aids, herpes before semiautomatics and crack... before SEGA or Super Nintendo... WAY back!

I'm talking about sitting on the curb, sitting on the stoop...about hide-and-go-seek; Simon says and red-light-green-light. Lunch boxes with a thermos ... chocolate milk, going home for lunch, penny candy from the store, hopscotch, four-square, butterscotch, skates with keys, jacks and Cracker Jacks, hula hoops and sunflower seeds, wax lips and mustaches, Mary Jane's, saddle shoes and Coke bottles with the names of cities on the bottom.

Remember when it took five minutes for the TV to warm up.  When nearly everyone's Mom was at home when the kids arrived home from school.

When nobody owned a purebred dog.  When a quarter was a decent allowance. When you'd reach into a muddy gutter for a penny.  When your Mom wore nylons that came in two pieces. When all of your male teachers wore neckties and female teachers had their hair done everyday and wore high heels.

Remember running through the sprinkler, circle pins, bobby pins, Mickey Mouse Club, Rocky and Bullwinkle, Kookla, Fran and Ollie, Spin and Marty...Dick Clark's American Bandstand ... all in black and white and your Mom made you turn it off when a storm came.

When around the corner seemed far away, and going downtown seemed like going somewhere.  Climbing trees, making forts, backyard shows, lemonade stands, cops and robbers, cowboys and indians, staring at clouds, jumping on the bed, pillow fights, ribbon candy, angel hair on the Christmas tree, Jackie Gleason, white gloves, walking to the movie theater, running till you were out of breath, laughing so hard that your stomach hurt...remember that?

Not stepping on a crack or you'd break your mother's back ... paper-chains at Christmas, silhouettes of Lincoln and Washington, the smells of school, of paste and Evening in Paris.

What about the girl who dotted her i's with hearts? (that was before that stupid smiley face)!  The Stroll, popcorn balls and sock hops?

Remember when there were just two types of sneakers for girls and boys - Keds and PF Flyers, and the only time you wore them at school was for gym. And the girls had those ugly gym uniforms.

When you got your windshield cleaned, oil checked, and gas pumped, without asking -- all for free -- every time!  And, you didn't pay for air either, and you got trading stamps to boot!

When laundry detergent had free glasses, dishes or towels hidden inside the box.  When it was considered a great privilege to be taken out to dinner at a real restaurant with your parents.  When the worst thing you could do at school was flunk a test or chew gum.  And the prom was in the gym or the lunchroom and you danced to a real orchestra.  When they threatened to keep kids back a grade if they failed -- and did!  When being sent to the principal's office was nothing compared to the fate that awaited the student at home.

Basically, we were in fear for our lives, but it wasn't because of drive-by shootings, drugs, gangs, etc.  Our parents and grandparents were a much bigger threat!

But we survived because their love was so much greater than the threat.

Remember when a '57 Chevy was everyone's dream car -- used to cruise, peel out, lay rubber, scratch off or watch the submarine races?

When people went steady; and girls wore a class ring with an inch of wrapped Band-Aids, dental floss, or yarn coated with pastel-frost nail polish so it would fit their finger.

When no one ever asked where the car keys were because they were always in the car, in the ignition, and the car and house doors were never locked!

Remember lying on your back on the grass with your friends and saying things like “That cloud looks like a …”  And playing baseball with no adults needed to enforce the rules of the game.

Remember when stuff from the store came without safety caps and hermetic seals, because no one had yet tried to poison a perfect stranger.

And, with all our progress, don't you just wish, that just once you could slip back in time and savor the slower pace...and share it with the children of today?

So send this on to someone who can still remember Nancy Drew, The Hardy Boys, Laurel and Hardy, Howdy Dowdy and The Peanut Gallery, The Lone Ranger and Tonto, The Shadow Knows, Nellie Belle, Roy and Dale, Trigger and Buttermilk... As well as the sound of a real mower on Saturday morning, and Summers filled with bike rides, baseball games, bowling, visits to the pool ... and eating Kool-Aid powder with sugar from the palm of your hand.

There, didn't that feel good? Just to lean back and say:  “Yeah...I remember....…”.

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Crop Destruction, Crop Rescue & the Importance of Weed 
Control for Nematode Management
With the impending loss of methyl bromide, growers are becoming more aware of the importance of field histories and past pest population levels.  Nowhere is this more important than in the area of weed control.  New weed problems will continue to evolve and present challenges for growers.  Failure to adequately manage weeds within the field can not only affect crop yield, but serve as alternative hosts to nematodes.  Beginning fall 2001, studies were initiated in southwest and south-central Florida to evaluate the host status of various weeds to root-knot nematode.  The results clearly showed the excellent host status to root-knot nematode of many common weed species found in agricultural fields.

These common weeds included various species of pigweed, purslane, nightshade, eclipta, Carolina geranium, Gnaphalium, and a number of legumes such as  sesbania, sand vetch and clovers.  Somewhat surprisingly, even the grasses, including various species of crabgrass and goosegrass, served as hosts, albeit relatively poor hosts.  These results suggest that nematodes cannot be effectively managed unless weeds are also effectively and simultaneously managed.  Weeds which are allowed to grow and increase in numbers, particularly in-between mulch covered rows, serve to increase soil population densities of nematodes.

Another question addressed in recent research was whether it is possible to effectively reduce nematode population levels and restore crop yield potential once nematodes have colonized a root system.  Crop rescue studies were conducted to evaluate new chemigational strategies for postplant Vydate use in tomato.  Treatments included up to 3 Vydate applications per week, during either the first 6 weeks, last 6 weeks, or for the entire 11 week cropping season.  Results indicated that regardless of time of discovery in the field, roots which are heavily galled are not likely to respond satisfactorily (i.e. stage a dramatic comeback) to Vydate treatment.  So...the sooner a problem is identified, the greater the response will be.  When treatments are applied early enough to be effective, repeated weekly applications throughout the entire season was superior to either early or late application regimes.  Split applications are superior to single applications, i.e. 3X per week was better than 1X per week.

Field research also continues to explore the chemigational use of water soluble fumigants (Vapam, Kpam and Telone EC) for crop destruction and nematode management.  Recent trials in southwest and west central Florida have all demonstrated the feasibility of this approach.  For example, Telone EC (5-15 gal/treated acre) was evaluated at 4 locations for sting or root-knot nematode control and for post harvest crop destruction.  In these trials, Telone EC significantly reduced nematode populations and provided near complete mortality of plants within treated rows.  Results of trials during spring 2002 have also clearly demonstrated the ability to kill tomato, pepper and strawberry foliage via destruction of roots.  Soil populations of nematodes were also substantially reduced in the trials.  (Excerpted from FACTS Proceedings 2002, J. Noling and J. Gilreath)

Manatee Vegetable Newsletter
July-August 2002
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Herbicide Drift
Every year, growers in southwest Florida are impacted by herbicide spray drift which damages vegetables and other crops to varying degrees.  Many vegetables are considered to be susceptible crops which are sensitive to low concentrations of certain herbicides.

In some cases, the organo-auxin class of herbicides (2,4-D) have been implicated.  These materials are extremely volatile and liable to drift for long distances affecting susceptible crops under certain conditions.  In other instances, other herbicides have been implicated.  It is important to note that all herbicides have the potential to drift under the right conditions and can often move surprising distances impacting crops.

Using current application methods, chemical drift is an inevitable component of pesticide application.  The potential for drift can be minimized by increasing carrier volume, lowering the spray boom, using nozzles that create larger spray droplets, employing drift control adjuvants, and reducing spray pressure.  The best strategy to minimize spray drift is to avoid applications when wind conditions are high.  While this strategy may seem simple, it is the most effective and consistent drift control practice.  Because commercial applicators may not have much flexibility to modify application equipment, spraying when conditions minimize drift is their only effective means to avoid this problem.

Growers as well as right of way and aquatic weed management applicators should understand that under the Florida Pesticide Law they are required to make safe and timely applications, and can be held legally responsible for crop injury and losses resulting from drift.  The Florida Statues concerning Pesticides, Prohibited Acts (Chapter 487.031) states (13e) - It is unlawful for any person to apply any pesticide directly to, or in any manner cause any pesticide to drift onto, any person or area not intended to receive the pesticide.

The Florida Pesticide Law and Rules, Chapter 5E-2.033, specifically address the use of organo-auxin herbicides and places certain restrictions and prohibitions on the use of these materials in Hendry, Glades, Martin and Palm Beach Counties.

It is important to note that certain non-herbicide products, such as the plant growth regulator  Polado L, contains glyphosate which can cause severe damage to non-target crops if drift occurs.  In other cases, herbicide applications targeted at non-crop areas such as canals or right-of-ways may drift and affect near by crops.

On behalf of all agricultural producers please review your use of herbicides and other products and ensure that they are used in a way that will not cause damage to nearby crops.

If you would like more information on drift management or the Florida Pesticide Law, please contact me at the Hendry County Extension Office.
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Sweet Corn Research Technician
Syngenta Seeds, Inc., a world leading agribusiness company, is seeking a Research Technician for its Naples Research facility.

This position is responsible for processes of sweet corn seed development, such as, planting, pollination, harvesting.  Will also manage seed inventories, conduct disease inoculations, conduct computer data entry, & supervise seasonal employees.  HS diploma or equivalent required.  2 Years comparable exp, bilingual English/Spanish, PC Skills, & ability to travel 2-3 wks/yr preferred.  Competitive salary, an attractive benefits pkg, a drug free work place.  Send resume to: HR Dept., Job #E51, PO Box 4188, Boise, ID 83711 Fax: 208-327-7222 or e-mail to: resumes.rogers@syngenta.com
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Pesticide Potpourri
                     

                   - one pretransplant soil surface treatment of 0.5 to 0.75 ounces Sandea 75DF (0.024 to 0.036 lbs ai);
                   - one “over-the-top” application 14 days after transplanting of 0.5-0.75 oz. product; and/or
                   - postemergence application(s) of up to 1 ounce product (0.047 lb ai) to the row middles between planted rows
                        of tomatoes may be made.

        A 30-day PHI will be observed.  The Section 18 will expire on June 4, 2003.  The Section 18 was applied for and
        granted through efforts of the Florida Fruit and Vegetable Association (FFVA) and the Florida Department of Agriculture
        and Consumer Services (FDACS).  (Stall, Vegetarian 02-06)  Note:  There have been questions regarding a
        possible antagonism between Aim and Poast when Poast is added for grass control (such as paraquat resistant
        goosegrass).  This is based on the results of one trial.  Additional research is planned to determine if this is true
        antagonism or a fluke.  In that trial, Aim + Sandea also gave better control of eclipta than either material separately.
        (Dr. Bill Stall, personal communication)

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Platinum Insecticide in Florida
FIFRA Section 2(ee) Recommendation applies to the control of leafminers in tomatoes when Platinum 2SC Insecticide is applied at the rate of 8 oz/A at planting.  The user must refer to the federally approved label for Platinum 2SC and read and follow all directions for use, restrictions, and precautions.

DIRECTIONS FOR USE

 Platinum 2SC Insecticide may be applied to transplanted tomatoes at the time of planting at the rate of 8 oz/A to achieve early season control of leafminers.  Do not exceed 8.0 fluid oz. of Platinum 2SC (0.125 lbs. a.i.) per acre during a growing season.

The user must refer to the federally approved Platinum 2SC label and read and follow all directions for use, restrictions, and precautions.  It is a violation of federal law to use this product in a manner inconsistent with its labeling.

The user should have this recommendation in their possession at the time of use.

This recommendation is made as permitted by Section 2(ee) of FIFRA, as amended, and has not been submitted to or approved by the EPA.
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On the Lighter Side
An unemployed man is desperate to support his family.  His wife watches TV all day and his three teenage kids have dropped out of high school to run around with the local toughs.  He applies for a janitor’s job at a large firm and easily passes an aptitude test.

The human resources manager tells him, “You will be hired at minimum wage of $5.15 an hour.  Let me have your e-mail address so that we can get you in the loop.  Our system will automatically e-mail you all the forms and advise you when to start and where to report on your first day.”

Taken back, the man protests that he is poor and has neither a computer nor an e-mail address.

To this the manager replies, “You must understand that to a company like ours that means that you virtually do not exist.  Without an e-mail address you can hardly expect to be employed by a high-tech firm.  Good day.”

Stunned, the man leaves.  Not knowing where to turn and having $10 in his wallet, he walks past a farmers’ market and sees a stand selling 25 lb crates of beautiful red tomatoes.  He buys a crate, carries it to a busy corner and displays the tomatoes.  In less than 2 hours he sells all the tomatoes and makes 100% profit.  Repeating the process several times more that day, he ends up with almost $100 and arrives home that night with several bags of groceries for his family.

During the night he decides to repeat the tomato business the next day.  By the end of the week he is getting up early every day and working into the night.  He multiplies his profits quickly.  Early in the second week he acquires a cart to transport several boxes of tomatoes at a time, but before a month is up he sells the cart to buy a broken-down pickup truck.

At the end of  a year he owns three old trucks.  His two sons have left their neighborhood gangs to help him with the tomato business, his wife is buying the tomatoes, and his daughter is taking night courses at the community college so she can keep books for him.

By the end of the second year he has a dozen very nice used trucks and employs fifteen previously unemployed people, all selling tomatoes.  He continues to work hard.  Time passes and at the end of the fifth year he owns a fleet of nice trucks and a warehouse, which his wife supervises, plus two tomato farms that the boys manage.

The tomato company’s payroll has put hundreds of homeless and jobless people to work.  His daughter reports that the business grossed a million dollars.

Planning for the future, he decides to buy some life insurance.  Consulting with an insurance adviser, he picks an insurance plan to fit his new circumstance.  Then the adviser asks him for his e-mail address in order to send the final documents electronically.

When the man replies that he doesn’t have time to mess with a computer and has no e-mail address, the insurance man is stunned, “What, you don’t have e-mail?  No computer?  No Internet?  Just think where you would be today if you’d had all of that five years ago!”

 “Ha!” snorts the man.  “If I’d had e-mail five years ago I would be sweeping floors at Microsoft and making $5.15 an hour.”

Which brings us to the moral:

Since you read this on-line , you’re probably closer to being a janitor than a millionaire.

Sadly, I received it via e-mail also!!
 

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