What is the average tomato produced called

Other students of the same institution are also working on breeding for processing quality and Bacteria Wilt-resistant tomato varieties. Tomato is indispensable in all Ghanaian recipes and contributes significantly to the economy of Ghana. This review presented tomato production trends in Ghana, past tomato-breeding programmes that have been carried out as well as some potential tomato-breeding objectives.

Ghana will achieve self-sufficiency in tomato production if the government, Universities, Research Centres and National Research Institute NRI will invest more resources into tomato breeding to achieve both the short- and long-term-breeding objectives.

This review will serve as a reference for improving tomato in the country. I would like to thank Mr. Emmanuel K. Quartey and Mrs. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.

Help us write another book on this subject and reach those readers. Login to your personal dashboard for more detailed statistics on your publications. Edited by Seloame Tatu Nyaku. Edited by Sven Bode Andersen.

We are IntechOpen, the world's leading publisher of Open Access books. Built by scientists, for scientists. Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals. Open access peer-reviewed chapter Review on Tomato Solanum lycopersicum, L. Downloaded: Abstract Tomato is an important component of every Ghanaian meal, and its cultivation contributes significantly to livelihood improvement.

Keywords tomato unsystematic breeding programmes agronomic morphological molecular. Introduction Tomato Solanum lycopersicum, L. Germplasm collection and genetic diversity studies Germplasm is required for the commencement of any breeding programme. Marker no. Table 1.

Tomato microsatellite markers used in DNA fingerprinting among five tomato accessions. Breeding for biotic stress Post has seen some breeding efforts made in screening tomato accessions against biotic stresses. Screening germplasm for tomato yellow leaf curl disease resistance TYLCD is a major tomato disease in Ghana and Africa as a whole and can lead to a massive yield loss and consequent impact on livelihood if the vector of the disease whitefly is not controlled and infection starts at an early stage of the plant growth [ 45 ].

Table 2. Table 3. Scott, Univ. Zamir, Hebrew Univ. Table 4. Table 5. Table 6. Table 7. V Fadzebegye Ghana Central region. Table 8. Williamson UC82 Suscept. Table 9. Tomato cultivars evaluated for nematode resistance. Screening for abiotic stress Another important tomato-breeding objective is breeding for abiotic stress; nonetheless, there is limited published work on screening of tomato against abiotic stresses in Ghana.

Table Tomato cultivars used for the heat stress. Potential tomato breeding objectives Tomato varieties currently grown in Ghana are generally acidic, watery, poor in color, poor shelf life and susceptible to TYLCV as well as intolerant to heat.

More Print chapter. How to cite and reference Link to this chapter Copy to clipboard. Cite this chapter Copy to clipboard Leander D.

Review on Tomato Solanum lycopersicum, L. Available from:. Over 21, IntechOpen readers like this topic Help us write another book on this subject and reach those readers Suggest a book topic Books open for submissions. More statistics for editors and authors Login to your personal dashboard for more detailed statistics on your publications.

Access personal reporting. More About Us. Ty-1 Ty-1 S. Tyking, LA L. The census showed that the largest growth was in farms producing tomatoes on five acres or less. This may be attributed to the increase in the number of small-scale vegetable farms producing for the local market. In , approximately 12, Tomatoes are warm-season crops and are sensitive to frost at any growth stage, so field planting in temperate climates occurs after the threat of frost is past in the spring or transplants are planted and grown under row covers in late spring.

Tomatoes produced in temperate climates are also grown in greenhouses and under plastic covered high tunnels to extend the production season. The emergence of greenhouse tomato production has begun to change the shape of the U. Greenhouse tomato production allows producers to grow fresh tomatoes in structures, sometimes using methods of climate control and alternative soils.

Advantages of greenhouse production include uniform appearance and quality, consistency in production, increased yields per acre and enhanced grower capability to sustain year-round production. The national yield per acre average for field-grown fresh and processed tomatoes was Pacific Coast Producers.

Three Guys Farms. These cracks may heal, forming a rough texture on the fruit; generally these fruit are unmarketable. As with many of these disorders, it is unclear what causes this, but it is associated with rain events. Heavy rains following dry periods are times when this is most likely to occur.

Lime and fertilizer management should be tailored to apply optimal amounts of lime and nutrients at the most appropriate time s and by the most effective application method s. Fertilizer management is impacted by cultural methods, tillage practices and cropping sequences.

A proper nutrient management program takes into account native soil fertility and residual fertilizer. Therefore, the first step in an appropriate fertilizer management program is to properly take a soil test 3 to 5 months before the crop is to be planted. Adjusting the soil to the appropriate pH range is the first consideration for any fertilizer management program. The soil pH strongly influences plant growth, the availability of nutrients, and the activities of microorganisms in the soil.

It is important to keep soil pH in the proper range in order to produce the best yields of high quality tomatoes. Soil tests results indicate soil pH levels and also provide recommendations for any needed amounts of lime required to raise the pH to the desired range. The optimum pH range for tomato production is 6. Most Georgia soils will become strongly acid pH 5. Continuous cropping and application of high rates of nitrogen reduce pH at an even faster rate.

Lime also adds calcium and, with dolomitic lime, magnesium to the soil. Calcium has limited mobility in soil, so broadcast and thoroughly incorporate lime to a depth of 6 to 8 inches. This will also neutralize soil acidity in the root zone. To allow adequate time for neutralization of soil acidity raising the pH , lime should be applied and thoroughly incorporated 2 to 3 months before seeding or transplanting.

However, if application cannot be made this early, liming will still be very beneficial if applied and incorporated at least 1 month prior to seeding or transplanting. The two most common liming materials available in Georgia are calcitic and dolomitic limestone. Dolomitic limestone also contains 6 to 12 percent magnesium in addition to calcium. Since many soils, and particularly lighter Coastal Plains soils, routinely become deficient in magnesium, dolomitic limestone is usually the preferred liming material.

Recommending a specific fertilizer management program universal for all tomato fields would result in applications that are inefficient and not cost effective. In addition to crop nutrient requirements and soil types, fertilizer recommendations should take into consideration soil pH, residual nutrients and inherent soil fertility. Therefore, fertilizer recommendations based on soil test analyses have the greatest potential for providing tomatoes with adequate but not excessive fertility.

Applications limited to required amounts result in optimum growth and yield without wasting fertilizer or encouraging luxury consumption of nutrients, which can negatively impact quality or cause fertilizer burn.

Recommendations based on soil tests and complemented with plant tissue analyses during the season should result in the most efficient lime and fertilizer management program possible. Valid soil sampling procedures must be used to collect the samples submitted for analyses, however. Soil samples that are improperly collected, compiled or labeled are of dubious benefit and may actually be detrimental. If you have questions about soil sampling, please contact your local county extension office for information.

In addition to lime application, preplant applications and in-season supplemental applications of fertilizer will be necessary for good crop growth and yield.

In general, preplant applications are made prior to installation of plastic mulch. Research shows that broadcasting over the entire field is usually less effective than banding. For example, on a inch wide bed, a swath 24 inches to 48 inches wide of fertilizer is uniformly applied centered over the bed and incorporated by roto-tilling.

Additional applications are then made through the drip irrigation system. In bareground culture, pre-plant applications are followed by one to three side-dressed applications. The general crop requirements and application timings for the various nutrients are discussed below. Fertilizer materials dissolved in water and applied to the soil around plant roots at or just after transplanting are called starter solutions.

When proper formulations and rates are applied, they can promote rapid root development and early plant growth. Common starter solutions consist of 3 pounds of a formulated material such as , which weighs approximately 11 lbs. In addition to supplying phosphorus, which may be inadequately available especially in cold soils in the early spring , the starter solution supplies water and firms the soil around roots.

This helps eliminate air pockets that can cause root drying and subsequent plant or root damage. A starter solution is no substitute for adequate rainfall or irrigation after transplanting, however. If the starter solution is too highly concentrated mixed too strong , it can kill plant roots and result in dead or stunted plants.

When mixing and applying from a large tank, mix a fresh solution only after the tank becomes empty. This helps prevent the gradual increase in concentration that will occur if a portion of the previous mix is used for a portion of the water component in subsequent batches.

If a dry or crystalline formulation is used, be sure it is thoroughly mixed and agitated in the tank, since settling can result in streaks of highly concentrated application that can stunt or kill plants. Table 4 indicates the pounds of fertilizer nutrients recommended for various soil P and K levels according to University of Georgia soil test ratings of residual phosphorus P 2 O 5 and potassium K 2 O.

All the recommended phosphorus should be incorporated into the bed prior to plastic mulch installation or, for bare ground production, applied during or near transplanting. For early growth stimulation in bare ground culture, pop-up fertilizer should be banded 2 to 3 inches to the side of the plants and 2 to 3 inches below the roots.

A good pop-up fertilizer has approximately a 1 to 3 N to P ratio. It should be relatively high in phosphorus and low in potassium. One-third to one-half of the potassium should either 1 be incorporated into the bed prior to installing plastic mulch, or 2 be applied in two bands, each located 2 to 3 inches to the side and 2 to 3 inches below the level of plant roots for bare ground production. The remainder of the recommended potassium should be applied through the drip system according to the schedule in Table 5 or, for bare ground culture, in one to three applications as needed.

It can be banded in an area on both sides of the row just ahead of the developing root tips. The maximum number of applications is usually more effective on sandy soils. Typical Coastal Plains soils require a total of to pounds of nitrogen N per acre.

Extremely sandy soils may need additional N or an increased number of applications. Piedmont, Mountain and Limestone Valley soils usually require only to pounds of N per acre for tomato production. Nitrogen rates actually needed will vary depending on rainfall, soil type, soil temperature, irrigation, plant population, duration of the harvest season, and method and timing of applications. Excessive N applications can delay maturity, cause rank vine growth at the expense of fruit set, and reduce shipping quality of fruit.

For typical Coastal Plains soils, one-third to one-half of the recommended nitrogen should either 1 be incorporated into the bed prior to plastic installation or, 2 with bare ground culture, applied in two bands, each located 2 to 3 inches to the side and 2 to 3 inches below the level of plant roots. Apply the remaining recommended N through drip irrigation according to the schedule in Table 5. On bare ground, one to three side dressed applications possibly four to five applications for extended harvest period on very sandy soil are needed.

For heavier Piedmont, Mountain and Limestone Valley soils, one to two applications are usually sufficient. Approximately 50 percent of the total applied N should be in the nitrate form. High rates of ammoniacal nitrogen may interfere with calcium nutrition and result in an increased incidence of blossom-end rot BER.

Side dressing with calcium nitrate as the nitrogen source often significantly reduces the severity of BER. If the soil test indicates magnesium is low and if lime is recommended, apply dolomitic limestone. If magnesium is low and lime is not recommended, apply 25 pounds of elemental magnesium per acre. Apply a minimum of 10 pounds of sulfur per acre and, if soil test indicates low, apply 1 pound of actual boron per acre and 5 pounds of actual zinc per acre.

These nutrients should be supplied in the pre-plant fertilizer application. The fact that plants can absorb some fertilizer elements through their leaves has been known for some time. Leaves of many vegetable plants, however, are not especially well adapted for absorbing nutrients because of a waxy cuticle. In some instances, plants that seem to benefit from foliar uptake are actually benefitting from nutrient spray that reaches the soil and is taken up by roots.

The effectiveness of applying macronutrients such as nitrogen, phosphorus and potassium to plant leaves is questionable. It is virtually impossible for tomato plants to absorb enough N, P or K through the leaves to fulfill their nutritional requirements; furthermore, it is unlikely that they could absorb sufficient amounts of macronutrients to correct major deficiencies.

Although nitrogen may be absorbed within 24 hours after application, up to f4 days are required for potassium uptake, and 7 to 15 days are required for phosphorus to be absorbed from foliar application.

The crucial question is whether or not foliar N, P or K actually increases yield or enhances quality. Although some growers feel that foliar fertilizer should be used to supplement a soil applied fertilizer program, research findings do not support this practice.

If proper fertilizer management of soil applied nutrients is used, then additional supplementation by foliar fertilization is not usually required. Foliar nutrients are often expected to cure a variety of plant problems, many of which may be unrelated to nutrition. They include reducing stress induced blossom drop, aiding in healing frost or hail damaged plants, increasing plant resistance to various stresses and pests, etc. Nutrients are only effective as long as they are supplying a nutritional need, but neither soil-applied nor foliar-applied nutrients are panaceas.

Quite often after frost or hail occurs, tomato growers apply foliar nutrients to give the plants a boost to promote rapid recovery. What they do need is time and the proper environment for the normal recovery processes to occur. In addition, the likelihood of significant nutritional benefits from a foliar application of fertilizer to plants that have lost most of their leaves or have a large proportion of their leaves severely damaged is questionable.

Foliar application of sulfur, magnesium, calcium and micronutrients may help alleviate deficiencies. They should be applied, however, only if there is a real need for them and only in quantities recommended for foliar application.

Foliar applications of calcium nitrate or calcium chloride one to three weekly applications beginning at first bloom or at first sign of BER may reduce the incidence of blossom-end rot BER , but there is little evidence indicating this is an effective practice. If attempted, the recommended rate is 3 to 4 pounds in gallons of water per acre.

Two to three foliar applications of water soluble boron approximately 1 to 2 ounces by weight of actual boron per application at weekly intervals coinciding with flowering has in some instances enhanced fruit set.

A commercial formulation that contains both boron and calcium 2 to 3 ounces by weight of calcium per application may be applied. Plant tissue analysis or petiole sap analysis is an excellent tool for measuring the nutrient status of the crop during the season.

Particularly with fertigation, it is simple to adjust fertilizer injection rates according to the analysis results. Sufficiency ranges for tissue analysis are in Tables 6 and 7 and are for first flower stage and first ripe fruit stage, respectively, with the sample taken from the most recently mature leaf.

Fresh sap can be pressed from the petioles of tomato plants and used to determine nitrogen and potassium nutritional status.

Sufficiency ranges for these are listed in Table 8. Maynard, Donald M. New York. Olson, S. Maynard, G. Hochmuth, C. Vavrina, W. Stall, M. Momol, S. Webb, T. Taylor, S. Smith, and E. Edited by S. Olson and E. Gainesville, Fla. The equipment used for applying liquid insecticides, fungicides, herbicides and foliar fertilizers are classified as sprayers. Basically, there are two types of sprayers recommended for spraying tomatoes — hydraulic and air-curtain boom.

The key to maximum coverage with insecticide and fungicides is the ability of the air within the plant canopy to be replaced with pesticides.

The air-curtain booms Figure 1 are designed with an external blower fan system. Some sprayers provide a shield in front of or behind the conventional spray pattern, protecting the spray from being blown off-target.

The concept of this approach is to increase the effectiveness of pest-control substances, provide better coverage to the underside of leaves, promote deeper penetration into the crop canopy, make it easier for small droplets to deposit on the target, cover more acres per load, and reduce drift.

Studies conducted by the USDA Agricultural Research Service in Stoneville, Mississippi, have shown that the air-assisted sprayers tended to show improved insect control in the mid to lower canopies.

The air stream tended to open the canopy and help spray particles penetrate to a deeper level. Mid- to lower-canopy penetration and coverage is important when working with insecticides and fungicides, but may not be as critical when applying herbicides.

The hydraulic boom sprayers Figure 2 get their name from the arrangement of the conduit that carries the spray liquid to the nozzles. Booms or long arms on the sprayer extend across a given width to cover a particular swath as the sprayer passes over the field. Each component is important for efficient and effective application.

Most materials applied by a sprayer are a mixture or suspension. Uniform application demands a uniform tank mix. Most boom sprayers have a tank agitator to maintain uniform mixture. The agitation mixing may be produced by jet agitators, volume boosters sometimes referred to as hydraulic agitators and mechanical agitators.

These can be purchased separately and put on sprayers. Make sure an agitator is on every sprayer. Some growers make a mistake of not operating the agitator when moving from field to field or when stopping for a few minutes.

Always agitate continuously when using pesticides that tend to settle out. Nozzle tips are the most neglected and abused part of the sprayer. Since clogging can occur when spraying, clean and test nozzle tips and strainers before each application. When applying chemicals, maintain proper ground speed, boom height and operating pressure. The type of nozzle used to apply herbicides is one that develops large droplets and has no drift. The nozzles used for broadcast applications include the extended range flat fan, drift reduction flat fan, turbo flat fan, flooding fan, turbo flooding fan, turbo drop flat fan and wide angle cone nozzles.

Operating pressures should be 20 to 30 psi for all nozzles except drift reduction and turbo drop flat fans, flooding and wide angle cones.

Spray pressure more than 40 psi will create significant spray drift with flat fan nozzles. Operate drift reduction and turbo drop nozzles at 40 psi. Operate flooding fan and wide angle cone nozzles at 15 to 18 psi. These nozzles will achieve uniform application of the chemical if they are uniformly spaced along the boom. Flat fan nozzles should overlap 50 to 60 percent. When applying insecticides and fungicides, use solid or hollow cone type nozzles. The two patterns that are developed by solid or hollow cone nozzles can be produced by different tip configurations.

One type tip, disc-n-core, consists of two parts. One part is a core swirl plate where the fluid enters and is forced through tangential openings. Then a disc-type hardened stainless steel orifice opening is added. Another type of tip that produces the same patterns is of one-piece construction nozzle body.

Liquid is passed through a precision distributor with diagonal slots that produce swirl in a converging chamber. The resulting pattern of both tip configurations is either solid or hollow cone. Even fan and hollow cone nozzles can be used for banding insecticide or fungicides over the row. When applying insecticides and fungicides, it is advantageous to completely cover both sides of all leaves with spray.

When spraying tomatoes, use one or two nozzles over the top of the row up to 8 inches wide. Then as the plants start to grow and bush, adapt the nozzle arrangement for the various growth stages of plants Figures 3 and 4. Opposing nozzles should be rotated clockwise slightly so that spray cones do not collide. This will guarantee that the spray is applied from all directions into the canopy. As the plant increases in height, add additional nozzles for every 8 to 10 inches of growth. In all spray configurations, the nozzle tips should be 6 to 10 inches from the foliage.

Properly selected nozzles should be able to apply 25 to gallons per acre when operating at a pressure of 60 to or higher psi. Usually, more than one size of nozzle will be needed to carry out a season-long spray program. Calibrate sprayers often. Calibration should be conducted every 8 to 10 hours of operation to ensure proper pesticide application.

Plant diseases are one of the most significant limiting factors to tomato production in Georgia. The hot, humid climate coupled with frequent rainfall and mild winters favor the development of many pathogens and the diseases they cause. Bacterial spot is the most common and often the most serious disease affecting tomatoes in Georgia.

This disease is caused by the bacterium Xanthomonas axonopodis pv. Bacterial spot lesions can be observed on leaves, stems and fruit and occurs during all stages of plant growth. Leaf lesions usually begin as small water-soaked lesions that gradually become necrotic and brown in the center Figure 5.

During wet periods the lesions appear more water-soaked. Lesions generally appear sunken on the upper surface and raised on the lower surface of infected leaves. During periods of favorable weather, spots can coalesce and cause large areas of chlorosis Figure 6. Premature leaf drop is the ultimate result of leaf infection. Fruit lesions appear as small, round, dark brown to black spots Figure 7. The bacterium is primarily seed-borne and most epidemics can be traced back, directly or indirectly, to an infected seed source.

Infected seedlings carry the disease to the field, where it spreads rapidly during warm, wet weather. Workers working in wet fields can also be a major source of disease spread. All tomato seed planted for transplants, or direct seeded field grown tomatoes, should be tested by a reputable seed testing company.

Transplants should be inspected for bacterial spot lesions before being sold or planted in the field. Prevention is the best method for suppressing losses to bacterial spot. Purchase seed from companies that produce the seed in areas where the disease is not known to occur. Hot water seed treatment can also be used, and tomato seed can be soaked in water that is degrees F for 25 minutes to kill the bacterium. Transplant production should take place in areas away from commercial production to avoid contamination from production fields or vice versa.

Unlike pepper, tomatoes have little to no commercially available cultivars resistant to bacterial spot. Rotate away from fields where tomatoes have been grown within the past year and use practices that destroy volunteer plants that could allow the disease to be carried over to a subsequent crop.

Cull piles should be located away from production fields or transplant houses. Copper fungicides used in conjunction with maneb will suppress disease losses if applied on a preventive schedule with a sprayer that gives adequate coverage. Other bacterial-spot suppressive treatments are also available. Bacterial wilt, caused by Ralstonia solanacearum , is a devastating bacterial disease of tomatoes worldwide. This bacterium can last in the soil for several years and has been responsible for taking whole fields out of production.

Bacterial wilt is recognized by a rapid wilting of the tomato plant, often while the plant is still green Figure 8. Wilted plants will eventually die. A quick diagnostic tool is to cut a lower stem of a suspected infected plant and place it in a clear vial or glass of water and watch for the opaque, milky bacterial streaming that comes from the cut area Figure 9.

Bacterial wilt is not easily controlled by fumigation or chemical means. There are few commercially available cultivars with resistance to bacterial wilt. The best control tool is to rotate away from infested fields for several years.

Bacterial speck, caused by Pseudomonas syringae pv. Leaflet lesions are very small, round and dark brown to black. During favorable weather the lesions can coalesce and kill larger areas of leaf tissue. Bacterial speck causes oval to elongated lesions on stems and petioles. Tomato fruit may have minute specks with a greener area surrounding the speck. Control measures are similar to bacterial spot.

Virus diseases have been a severe limiting factor in tomato production in Georgia for several years. Most virus diseases cause stunting, leaf distortion, mosaic leaf discoloration, and spots or discoloration on fruit. The distribution of virus-infected plants is usually random with symptomatic plants often bordered on either side by healthy, non-symptomatic plants. Virus diseases are almost always transmitted by insect vectors, and the severity of a virus disease is usually tied to the rise and fall in the populations of these vectors from season to season and within a given season.

Some virus diseases are seed and mechanically transmitted. Only the viruses that have been the most problematic on tomato in Georgia will be covered in this section. This virus is transmitted by thrips and can affect tomato at any stage of development. The extensive host range of TSWV in weeds allows for a continual source of inoculum for infection.

As with any virus disease, however, early infections tend to cause more yield losses than those occurring later in plant development. Tomato fruit produced on infected plants may be misshapen, have dark streaks Figure 12 or have chlorotic spots Figure TSWV in Georgia tomato has been suppressed through the use of metalized plastic and other colored mulches as well as resistant varieties.

Cucumber mosaic virus CMV is a very common disease of tomato and can be very devastating where it occurs. This virus is transmitted by aphids and can be maintained in several weed species that surround production fields. The characteristic symptoms for CMV are severely stunted, distorted and strapped faciated leaves, stems and petioles.

Symptoms of CMV often resemble phenoxy herbicide injury. Few options are available for suppressing losses to CMV, but destruction of weed hosts that harbor the virus will aid help suppress disease spread. This is a virus that is whitefly-transmitted and is only a problem in years when whitefly populations are high.

Infected plants appear to be severely stunted and little to no yield can be obtained from these plants Figure Plant symptoms appear as severely stunted individual plants with greatly reduced leaves that take on a mouse-eared appearance Figure Tomato leaflets of infected plants may also have a distinct marginal chlorosis Figure This disease is often brought in on infected transplants and then spread by whiteflies, so transplant inspection is a must.

Identifying infected plants soon after transplanting and removing them will help prevent secondary spread. Preventive, systemic insecticide applications may prevent disease spread as well.

Early blight caused by Alternaria solani is the most common fungal disease of tomato foliage in Georgia. Leaf symptoms appear as round to oblong, dark brown lesions with distinct concentric rings within the lesion Figure Lesions are generally surrounded or associated with a bright yellow chlorosis.

Stem lesions are slightly sunken, brown and elongated with very pronounced concentric rings. Fruit may become infected around the calyx, and a velvety spore mass can often be observed on fruit lesions. The disease is introduced by wind or rain-splash and is carried over to subsequent crops on infested debris.

Wet, humid weather favors disease development. In the field, the fungus spores are spread mainly by wind. Unless controlled, it causes severe defoliation. Resistant varieties are available to avoid losses to early blight.

Rotation and deep turning are important for reducing initial inoculum. The disease is easily controlled with chemical sprays. Spray programs used for bacterial leaf spot will suppress early blight, but the addition of chemicals specifically targeted at early blight should be incorporated into the spray program.

Late blight caused by Phytopthora infestans. This is probably one of the best known tomato diseases worldwide, but it is a rare in Georgia except for occasional epidemics observed in north Georgia. This disease causes dark, water-soaked, greasy lesions on stems and foliage. A whitish-gray, fuzzy sporulation can be seen on the undersides of leaf lesions and directly on stem lesions during periods of high moisture.

A soft rot of fruit can also be observed. Phytopthora is a fungal-like organism that is in a separate kingdom than the fungi. It is a water-mold, oomycete organism that has a mobile swimming-spore stage as part of its life cycle.

The pathogen is carried by wind to non-infested areas, where it remains in the soil and on infested plant debris until favorable weather and a new host crop coincide to create a new epidemic. Warm days and cool nights coupled with adequate moisture favor the spread and infection of the late blight pathogen. Plant resistance to this disease is available but does not play a major role in disease control.

Destroying plant debris and rotating away from fields with a history of the disease is a must. Preventive fungicide sprays are generally relied on heavily where this disease occurs as a yearly problem. Septoria leaf spot Septoria lycopersici and Target spot Corynospora cassiicola are foliar fungal diseases of some importance in Georgia but are not generally a problem with the current spray regime that is targeted at early blight and bacterial spot.

Fusarium wilt caused by Fusarium oxysporum f. Fusarium wilt is a soilborne disease of tomatoes that is generally a problem in specific fields where the pathogen has been introduced.

The disease is initially brought into a field on infested seed, plant stakes, transplants or infested soil on equipment. Symptoms usually appear during hot weather and after fruit set has begun. Symptoms appear as a yellowing and wilting on one side of the plant at first, usually during the hottest part of the day, followed by the eventual complete yellowing and wilting of the plant Figure Entire death of the plant is the final result.

Vascular discoloration is often observed on stems above the soil line Figure This fungus can stay in the soil in a resting state for several years, and rotation away from these fields for years will lessen the severity but will not completely eliminate the disease. Fumigation really only delays disease onset and may lessen the total disease incidence. Preventing the disease from getting into the field is the best control measure, followed by the use of resistant varieties.

Several races of this disease occur, however, and resistance must be specific to the race of Fusarium that is in the field in question. Southern stem blight caused by Sclerotium rolfsii. This is a common destructive disease of tomatoes in Georgia. Since most tomatoes are rotated with peanuts, soybeans and other susceptible crops, the disease has become a major problem.

The fungus attacks the stem of the plant near or at the soil line and forms a white mold on the stem base. Later in the season, small, round brown bodies appear in the mold Figure Infected plants wilt and slowly die.

Vascular discoloration can be observed on stem tissues above the lesion. The severity of the disease can be lessened by following good cultural practices: rotation, litter destruction and deep turning with a moldboard plow are the best cultural defenses against this disease. Fumigation as well as at-plant and drip-applied fungicides are also effective in reducing losses to southern stem blight. Root-knot nematodes Meloidogyne spp can cause serious economic damage to tomatoes.

These tiny worms live in the soil and feed on the roots of tomatoes. Not only do they cause physical damage that interferes with the uptake of water and nutrients, but they allow the establishment of other diseases. Nematode infected plants are generally stunted with pale green to light yellow foliage.

Symptoms may be temporarily masked by supplying additional fertilizer and water. Soils infested with root-knot nematodes should be avoided or treated with fumigant or chemical nematicides before tomatoes are planted. Insect pests can damage tomato throughout the growing season, but severity varies with location and time of year. While many insects that feed on tomato are only occasional pests in Georgia, a few species are common pests and occur every season.

The severity of damage to tomato by insect pests is largely due to abundance of the pests, which is related to environmental conditions. With most insects, outbreaks are difficult to predict, and it is even more difficult to predict if control measures will be required. A knowledge of insect habits, careful pest monitoring and timely use of effective control measures will enable growers to avoid or at least reduce the damage they suffer.

Tomato is well suited for insect pest management. Because a variety of insects may attack tomato, scheduled sprays are frequently considered for insect management. Scouting two to three times per week, however, allowing for early detection of infestations and timely application of pest specific control measures, is the most cost-effective management strategy.

Possible exceptions to this are the management of thrips, which vector Tomato Spotted Wilt Virus, or fields with a history of specific pest problems that require preventive control or are difficult to manage with curative treatments. When insecticidal control is determined to be necessary, use the Georgia Pest Management Handbook to aid in selecting the correct insecticide for control of specific insect pests described in the following text.

Young tomato transplants may be cut down just above the soil surface by cutworms. While this damage is readily apparent, the insects are difficult to detect during the day as the larvae typically hide in the ground. Detection of the insects and verification of the pest problem is most easily accomplished when larvae are feeding at night.

The majority of cutworms pass the winter in the soil as full-grown larvae, and cutworm damage can be particularly abundant in fields where grass sod was the previous crop or in previously fallow fields with heavy weeds. Greatest damage is often found in wet areas of fields but can also be concentrated on field margins where cutworms are moving in from adjacent areas. Cutworms are generally considered a seedling pest, but they may also feed on foliage and fruit of mature plants.

Use preventive insecticide treatments on fields with a history of cutworms or on tomato fields following grass sod. Where preventive treatments are not used, use directed sprays for cutworm control when 5 percent of the seedlings have been damaged or destroyed and cutworms are still present.

All directed or foliar sprays used for cutworm control should be applied late in the day when cutworms are active. Other insects attacking the main stem of seedlings. Several occasional pests may cause damage similar to cutworms. White grubs immature stage of May beetles and June beetles may cut off plants, but they will typically cut plants slightly below the soil line as compared to cutworms, which will usually cut at or slightly above the soil line.

Vegetable weevils, crickets and grasshoppers may also attack the main stems of seedlings. Generally these pests do not cut off plants except for the smallest transplants.

They tend to feed up and down the main stem, removing the softer outer tissue, and can completely girdle the plant. This damage generally causes plant death and, at the least, makes the plant susceptible to lodging and seedling diseases. Threecornered alfalfa hopper may also attack seedlings. This pest has piercing-sucking mouth parts and does not remove plant tissue. This weakened area makes the plant susceptible to lodging. Thrips may be present in tomato fields throughout the growing season, but they are more prevalent in the spring.

Prior to plants blooming, tobacco thrips generally dominates the population since this species readily feeds and reproduces on foliage.

Flower thrips species populations can increase dramatically once blooming and pollen availability increases. Flower thrips populations may increase prior to the crop blooming if outside sources of pollen are plentiful. Plant injury is caused by both nymphs and adults Figure 21 puncturing leaf and floral tissues and then sucking the exuding sap.

This causes reddish, gray or silvery speckled areas on the leaves. With severe infestations, these areas can interfere with photosynthesis and result in retarded growth. Heavy infestations during the bloom stage may cause damage to developing fruit through egg laying.

This damage appears as dimples with necrotic spots in the center and may be surrounded by a halo of discolored tissue.

Occasionally thrips aggregate on fruit well hidden from sprays.