Tomato target spot

Target Spot is the name often used for vegetable diseases caused by the fungus Corynespora cassiicola. The name target spot derives from the ringed or bull's eye appearance sometimes seen in lesions caused by C. cassiicola. However, concentric rings are not always readily apparent in target spot lesions, and not all lesions with concentric ring are caused by C. cassiicola. It is often necessary to examine suspected target spot lesions for the characteristic spores of the causal fungus to ensure that a correct diagnosis is made. The pathogen can be induced to sporulate from diseased tissue after incubation in a high-humidity chamber for 24-48 hours. In some cases, growth of C. cassiicola from pieces of suspect tissue on agar media in the laboratory is needed to verify that target spot is, indeed, the problem.

Survival And Spread

In addition to tomato, this fungus has a wide host range and may attack such diverse crops as papaya, passion-vine, pepper, cowpea, cantaloupe, squash, and snap beans, as well as a number of common ornamentals.

The pathogen has several means for survival and spread in the field. It may survive up to two years in crop debris. The wide host range of this fungus also may contribute to survival of the fungus in Florida. The primary means of spread in the field is by airborne conidia.

Optimum conditions for disease development include temperatures from 68°F to 82°F and long periods of free moisture.

In trials, wounding was essential for reproduction of the fruit symptoms.

Symptoms

Target spot is frequently misdiagnosed in its early stages as symptoms are difficult to recognize and can be confused with bacterial spot and early blight. The name derives from the bull’s-eye appearance that is often displayed in lesions caused by the disease. Since concentric rings are not always visible and not all lesions with concentric rings are target spot, it is recommended a laboratory diagnosis be obtained to ensure that a correct diagnosis is made.

On tomato leaves and stems, foliar symptoms of target spot consist of brown-black lesions with subtle concentric rings giving them a target-like appearance. These can sometimes be confused with early blight. On tomato fruit, lesions are more distinct. Small, brown, slightly sunken flecks are seen initially and may resemble abiotic injury such as sandblasting. As fruits mature, the lesions become larger and coalesce, resulting in large pitted areas. Advanced symptoms include large deeply sunken lesions, often with visible dark-gray to black fungal growth in the center. A zone of wrinkled looking tissue may surround the margins of lesions on mature fruit.

Placing suspect fruit in a moist environment for 24 hours will often induce the growth of dark-gray mycelia providing telltale diagnostic evidence of target spot infection.

Management

Strategies for the management of this disease require an integrated approach for best results. Currently, target spot is controlled primarily by applications of protectant fungicides. It should be noted that tank-mix sprays of copper fungicides and maneb do not provide acceptable levels of target spot control. In recent trials at the University of Florida, fungicides were rated for efficacy as follows:

1. Switch (cyprodinil and fludioxonil), Inspire Super (difenoconazole and cyprodinil) both from Syngenta Crop Protection
2. Revus Top (mandipropamid and difenoconazole, Syngenta Crop Protection) and Scala (pyrimethanil, Bayer CropScience)
3. Tanos (famoxadone and cymoxanil, DuPont Crop Protection), Endura (boscalid, BASF), Quadris (azoxystrobin, Syngenta Crop Protection) and other strobilurins, and Reason (fenamidone, Bayer CropScience)
4. Bravo (chlorothalonil, Syngenta Crop Protection)
5. Mancozeb, Copper.

Southern blight on tomatoes

There are many different diseases and conditions that can harm your tomato plant and some of them are very invasive. Diseases that harm a tomato plant can end up killing the plant all together or it could invade the soil infecting other crops. A tomato plant is very fragile and you need to take care of it to ensure that a devastating disease does not occur. If you have a tomato plant then you need to check out the various diseases that can occur and learn how to prevent them from happening. One of the most devastating and intrusive tomato diseases you can get is the southern blight. Southern blight can wreck your tomato plant and make replanting impossible.

Southern blight is a condition that can infect a tomato and can present itself in two ways which are white mold and stem rot. Southern blight is caused from a soil-borne fungus and it is common on a lot of vegetables and fruits but is mostly seen on tomatoes. A tomato can be affected with southern blight at any stage and it is usually caused by environmental conditions. Environmental conditions such as moisture and high temperatures are often seen in a tomato plant suffering from southern blight. A tomato with southern blight will often show signs if it is infected and will show various symptoms.

About

Growing a garden full of tomatoes is a wonderful time of the summer to look forward to. Tomatoes are fairly simple to grow, taste great and have many uses. When a fungus or disease begins attacking these wonderful plants it can sometimes be difficult to determine what is the primary cause of the attack as there are several different primary causes ranging from pests to a fungus. When you know the difference in the diseases it makes treating the plants much more manageable.

Southern blight is a fungus that affects several vegetables including tomatoes. The southern blight fungus begins in the soil and will attack the stems, roots, leaves and fruit of the tomato plant. The fungus Sclerotium Rolfsii is the cause of Southern Blight. The fungus begins growth due to warm and moist weather creating a dry rot of a brownish color followed by a white development of fungus in the soil, near the lower part of the stem. The fungus prevents the plants from getting water and nutrients absorbed into them.

The first symptoms of the disease include drooping, yellowing and wilting of leaves on the tomato plant. The fungus can be present in the soil for several years and progression of the disease will spread to row upon row of plants and will greatly affect the ripe tomatoes that are close to the ground. The tomatoes affected with southern blight will have a slimy feel and bad smell.

Spread

The southern blight fungus can spread in infested organic matter or it can be infested in the soil itself. The soil surface is usually where the infestation of the southern blight will occur but it can also occur underneath the soil. Southern blight fungus is very invasive and can actually spread three feet through the soil which makes other plants susceptible to this disease. A whole row of tomato plants can be killed within a matter of a few days if the fungus ends up spreading throughout the soil. The tomato plants will die and the next crop will be severely infested with southern blight as well. It is hard to control the spread of southern blight once it starts because it is so invasive and spreads very quickly in the soil. If you live in a warm or moist environment then it will make it that much harder to control the southern blight. The best thing to do to stop southern blight from taking over your tomato plant is to prevent it in the first place.

Symptoms

The first symptoms of southern blight will often appear in the tomato while it is above the ground and consist of yellow leaves and wilting. The stem which is near the soil will look sunken and will feel very soft to the touch. The stem will also develop brown and black sports on the inside and outside as well. If you live in a moist environment then the tomato will have a white fungus growing on it near the lower stem. The white fungal growth can also be seen on the tomato if it is in contact with the soil and it will show up on crop debris surrounding the soil. If you think your tomato plant is infected with southern blight then there is a simple test you can do. Simply place a part of the lower stem in a paper towel that is wet and then place it inside a closed plastic bag. Keep it in there for 24 hours and then see if the white fungus develops, and if it does then you know your tomato plant has southern blight.

The initial symptoms of southern blight is a rapid wilting of the entire plant. A water-soaked lesion on the stem near the soil line rapidly expands, turns brown, and girdles the stem. A white mold (mycelium) eventually covers the stem lesion and surrounding moist soil. Small, uniformly round structures about 1/16 inch in diameter, called sclerotia, form on the mycelium. Sclerotia are first white, later becoming brown, and resemble mustard seeds. The presence of the white mycelium and sclerotia at stem base of afected plants are very useful characteristics for identifying southern blight. The fungus survives in the soil as sclerotia which may build to high numbers when susceptible plants are cropped repeatedly. After sclerotia germinate, the fungus must first colonize organic debris near the soil surface before the fungus can cause infection. The disease is favored by high humidity and soil moisture and warm to hot temperatures (85-95 F).

Prevention

When southern blight is first noticed or there are only a few plants scattered throughout the garden that have been affected, remove the plants that have been affected as well as the soil around them. When removing the soil there should be a minimum of six inches both in depth and surround the plant removed. Also rotating the crops that have not yet been affected by the fungus may prevent them from getting the disease.

Once the fungus is in the soil it may be difficult to control but, southern blight can be prevented in the next crop planting if proper measures are used. When planting begins, wrap the stems of the tomato plant with a small piece of aluminum foil in soil that has be replaced with un-diseased soil. Plant the tomato plants wrapped in foil two inches above the ground with approximately two inches above ground. When watering or cultivating, try to avoid getting any of the soil on the foliage as well. Caging or staking the tomato plants will also help to prevent southern blight and using mulch as a protective barrier may also be helpful and keep the garden weeded as well as removing dead leaves and etc. that may blanket the fungus causing it to spread.

Control

Southern blight is difficult to control when conditions favor the disease and when numbers of sclerotia in the soil are high. Crop rotation with a non-susceptible grass crop such as corn is the most effective means of reducing numbers of sclerotia and resulting indicidence of southern blight. Avoid planting tomato following a very susceptible crop such as peanut. Plant residues should be thoroughly incorporated into the soil prior to transplanting so that their presence on the soil surface does not encourage southern blight development. Side-dressing with ammonium nitrate rather than other forms of nitrogen and use of a soil fungicide at transplanting may provide some control. Please contact your local county extension office for current information. Here are some steps given to control the disease:

Non-chemical control

If you have tomato plants then you should rotate it with other crops such as cotton or corn to help stop the disease from infesting the tomato plants. You also want to make sure that you do not plant the tomato plant in the same location more than once in five years to ensure the soil is safe and not infested with southern blight. Plowing the soil very deep can also stop the infestation of southern blight and it can bury the old tomato plant debris. Planting your tomatoes further apart can also help stop southern blight from occurring because the plant will be getting more air and ventilation which can stop the moist environmental conditions. The planting of the tomatoes further apart can also help an infected tomato plant and will keep it from spreading to other plants and invading the soil. If you really want to make sure that southern blight does not take over, you can fumigate your soil which can stop the disease from spreading. Soil fumigation will not rid the soil of the southern blight but it can help control the disease and make it harder for it to spread through the soil.

Chemical control

There are many good fungicides available that will help to prevent the southern blight as well. When using a fungicide they can be sprayed or dusted , however the spray is usually more affective than a dust. For the most effective type of fungicide for southern blight in your area it is recommended that you visit a local garden store for suggestions of a fungicide that will work best in a particular part of the country.

Sour rot on tomatoes

Sour rot is a common decay of tomatoes everywhere they are cultivated, especially when temperatures are above 30°C. The decay can start in cracks, cuts, or insect bites in the skin of the fruit or at the brim of the scar of the stem. The disease develops rapidly, and the affected tissues become soft and watery. The skin in the affected area cracks, and a white, gaseous scum with a sour smell forms. At this stage, there is a proliferation of fruit flies, Drosophila melanogaster, which distribute spores and fragments of mycelium to other fruit with lesions of the skin. Sour rot can be diminished with careful management from the field to the shelf.

Sour rot is caused by Geotrichum candidum, a common soil-borne fungus that causes the disease not only in tomatoes, but also in citrus fruits and vegetables. Also, it can be a contaminant on tomato-handling equipment.

Symptoms

Numerous fungi cause fruit rots on tomato. Lesions are water-soaked, and may have a white scummy growth in the cracks. Lesions often occur near the stem end scar. The sour-rot pathogen is a type of yeast. Fruit lesions may initially be watery, but later become coated with fungal growth. This growth on infected fruit resembles a thick, gelatinous mass similar in appearance to cottage cheese and remains relatively firm unless a secondary infection by a soft rot bacterium occurs. The odor of these lesions is distinctive and is similar to that produced by lactic acid bacteria, hence the disease name, sour rot.

About and damage

G. candidum, like other fruit-rotting organisms, is an opportunistic pathogen that can live on plant debris in the soil. Because it is a saprophyte, it is ubiquitous in the natural environment and can be found in almost all soils. The sour rot organism may be windborne or splashborne on soil particles to surfaces of fruit in the plant canopy. Tomatoes are most resistant when they are relatively dry and firm. Mature green tomatoes are more resistant than are ripe fruit.

Mechanical injuries that occur during harvest and handling are a frequent site for decay development beginning on the fruit surface. Chilling injury and water congestion can compromise a tomato fruit’s natural resistance to decay and allow sour rot to develop and produce a watery decay.
Periods of persistent rainfall, fogs following rainfall, cool mornings, or exposure to chilling temperatures in the field can increase the incidence of sour rot.

Harvest and transport of wet fruit also can result in an increased incidence of disease. The potential for development of sour rot and other decays after harvest will be lowest if the plants are dry and free of decay at the time of harvest. When harvested and placed in bins, infections can spread to adjacent and nearby fruit, leading to a nest of infection.

Control

• Fruit should be kept off the soil (if possible), and surface wetting should be minimized. 
• Furrow or drip irrigation is preferred over sprinkler irrigation.
• Preventative fungicide sprays may be required if a “zero tolerance” for defects production system is needed.

Septoria leaf spot on tomatoes

During periods of high humidity and temperatures between 60 and 80 degrees Fahrenheit, an opportunistic fungal infection can wreak havoc on your tomato plants. Caused by the fungus Septoria lycopersici, septoria leaf spot is characterized by circular spots that range in diameter from 1/16 to 1/4 inch and appear either tan, dark brown or gray. The fungus is spread through infected plants and equipment and, if left untreated, will pass quickly and affect a whole crop, no matter what the plant’s age. Prevention, proper sanitation measures and the use of copper-based fungicides are the best ways to stop septoria leaf stop from spreading.

Septoria leaf spot, also called Septoria blight, is a very common disease of tomatoes. It is caused by a fungus (Septoria lycopersici) and can affect tomatoes and other plants in the Solanaceae family, especially potatoes and eggplant, just about anywhere in the world.

Although Septoria leaf spot is not necessarily fatal for your tomato plants, it spreads rapidly and can quickly defoliate and weaken the plants, rendering them unable to bear fruit to maturity.

Causes

Fungus spores are very good at hiding out and waiting for ideal conditions. They can travel great distances, in hopes of finding those conditions. The Septoria lycopersici fungus lives on the fallen tomato plant debris and weeds on and in the soil. It is spread to the plants by both water and wind, usually splashing up on the plants from the soil. Warm (60 - 80 F.), damp conditions are the most favorable for Septoria leaf spot to develop and that's when you should be most watchful. If caught early, it can be controlled.

Symptoms

Septoria leaf spots start off somewhat circular and first appear on the undersides of older leaves, at the bottom of the plant. They are small, 1/16 - 1/8 in. (1.6 - 3.2 mm) in diameter, with a dark brown margin and lighter gray or tan centers.

As the disease develops, the spots will get larger and may merge together. If you view them under a magnifying lens you may see the fruiting bodies of the fungus, which look like dark brown pimples, as shown in the second image. This is one of the symptoms that distinguishes Septoria leaf spot from other leaf spotting diseases.

Although the symptoms usually occur on the older, lower leaves, the disease can develop at any stage in the tomato plant's life. They may also appear on the stems, as shown in the last photo, as well as the blossoms and calyxes. They rarely affect the fruits.

If untreated, Septoria leaf spot will cause the leaves to turn yellow and eventually to dry out and fall off. This will weaken the plant, send it into decline and cause sun scalding of the unprotected, exposed tomatoes. Without leaves, the plant will not continue producing and maturing tomatoes. Septoria leaf spot spreads rapidly.

• Lower leaves show symptoms first
• Round, yellow or water-soaked spots appear on the undersides of leaves. They quickly emerge on leaf tops and turn to black or brown with tiny black dots in the center.
• Heavily infected leaves turn completely yellow, then brown, and fall.
• Spotting works its way up the plant and can infect stems.
• Septoria leaf spot does not display characteristic “target” or concentric spots seen in early blight.
• Fruit is rarely infected.

When does it attack your plants?

• It can attack at any point in the season
• It strikes frequently in early to mid-season
• It’s most common in humid weather
• It often affects tomato plants after a period of heavy rainfall

Prevention

• Rotate crops. Although it doesn’t live in the soil, Septoria can survive in garden debris, perennials, and weeds for 3 years.
• Plant tomatoes in a raised bed to improve drainage and prevent diseases from spreading.
• Choose strong hybrid varieties to increase chances of plants remaining disease-free during the season.At last check, there are no tomato varieties resistant to Septoria.
• Give tomato plants extra space (more than 24 inches) to let air to move and keep leaves dry.
• Water the soil – not the plants – to prevent splashing. Avoid overhead watering.
• Stake tomato plants for better circulation.
• Mulch with black plastic or landscape fabric to prevent fungus from spreading up onto leaves.
• Remove and destroy affected plants at the end of the season.

Treating an affected plant

1. Inspect the tomato seedling before planting. While at the home improvement store or nursery, look for the early signs of septoria leaf spot, including the tan, brown or gray rings. Only introduce plants that appear healthy and disease-free.
2. Choose a planting site featuring well-drained soil and plenty of exposure to light winds and the sun. Septoria spreads more quickly on moist leaves, so choose an area that allows the plants to remain as dry as possible.
3. Spread a thin layer of mulch around the growing tomato seedlings. The mulch acts as a protective shield that doesn’t allow septoria spores to splash onto the tomato stems or leaves during irrigation.
4. Irrigate the plants early in the day and, if possible, avoid using an overhead watering system. Watering near the base of the plant helps keep the foliage relatively free of excess moisture, which the septoria requires to thrive.
5. Monitor your growing tomato plants and pluck off any diseased leaves immediately after you notice the infection. The infection generally starts on the lower leaves and moves up. Toss or burn the infected leaves. Never mulch or compost them, as this will only spread the septoria fungus.
6. Treat the tomato plants with a copper-based fungicide at the first sign of the septoria infection, or right after the formation of fruit clusters. Apply the product to both sides of the tomato leaves and the center stock. To help control the spread of septoria to the plant’s other leaves, reapply the fungicide every seven to 14 days.

Precautions

You probably won't be able to avoid Septoria leaf spot all together. It is very wide spread and given the ideal conditions, it will try to take hold in your garden. However there are some precautions you can take to lessen its impact and prevent it from spreading further.

• Use disease free seed. There's no evidence that it is carried by seeds, but err on the safe side and don't save seed from infected plants.
• Start with a clean garden. Dispose of all affected plants. The fungus does not remain in the soil, but it can over-winter on the debris of diseased plants. So it's important to dispose of all the affected plants far away from the garden and the compost pile. Keep in mind that it may have spread to your potatoes and eggplants, too.
• Avoid overhead watering. Water aids the spread of Septoria leaf spot. Keep it off the leaves as much as possible by watering at the base of the plant only.
• Provide room for air circulation. Leave some space between your tomato plants so there is good air flow. Stake them so that they are not touching the ground and not all bunched together. Good air circulation is especially important during damp and rainy periods.
• Mulch below the plants. A layer of mulch will prevent spores on the ground from splashing up onto the lower leaves.
• Consider organic fungicide options. Fungicides containing either copper or potassium bicarbonate will help prevent the spreading of the disease. Serenade® has also shown good promise. Begin spraying as soon as the first symptoms appear and follow the label directions for continued management.
• Plant next year's tomatoes in a different section of your garden. In small gardens, it's not always practical to rotate your crops, so good clean up and sanitation become even more important.

Other options

• Remove and destroy infected leaves (be sure to wash your hands afterwards to keep fungus from spreading unnecessarily).
• Treat organically with copper spray, which you can purchase at the hardware store or home improvement center. Follow label directions. You can apply until the leaves are dripping, once a week and after each rain.
• Once blight is present and progresses, it becomes more resistant to biofungicide and fungicide. Treat it as soon as possible and on a schedule.

Rhizopus soft rot on tomatoes

Rhizopus soft rot (Rhizopus stolonifer) is a widely distributed thread-like Mucoralean mold. Commonly found on bread surfaces, it takes food and nutrients from the bread and causes damage to the surface where it lives.

Symptoms

Rhizopus soft rot occurs as large water-soaked areas which become soft and sunken in time. Gray whiskery mold with dusty black spores may grow on the fruit surface and within the seed cavity.

Prevention

Postharvest fungicide applications are effective against Rhizopus soft rot. Avoid injuring fruit during harvesting and handling and maintain proper temperature control during storage and transit.

Rhizoctonia rot

Rhizoctonia solani is common in most soils and is able to cause some form of disease in almost all cultivated plants. Different 'strains' of R. solani, called anastomosis groups, have been recognized. The anastomosis groups differ in their host range and pathogenicity.

The most common diseases are damping-off of seedlings, root and stem rots, stem cankers and fruit rot. The diseases often have common names that describe symptoms on the particular host, for example base rot of lettuce, black scurf of potato tubers, crater rot of beetroot, and wire stem of tomato and crucifer seedlings.

It is caused by fungus Rhizoctonia solani.

Symptoms

Infection of stems causes dark-coloured cankers or rotting at the base of the stem. On plants growing close to the ground (e.g. lettuce), the fungus attacks the older leaves in contact with the soil, causing brown lesions on the leafstalks and leaves. The disease may progress to involve the whole plant, causing wilting and death.

On fleshy, succulent stems, roots and storage organs, the fungus causes brown, rotten areas or sunken cankers that may be covered by fungal mycelium. Infection of potato tubers causes black scurf in which small, dark, flat sclerotia resembling specks of dirt occur on the tuber surface and which are not removed by washing. Fruit growing near the ground can be infected, developing firm, water-soaked areas that become sunken and often crack open.

Control

Cultural and non-chemical control

Prevent fruit from contacting the soil by staking plants and using plastic mulches. Varieties highly susceptible to Rhizoctonia fruit rot should be avoided, especially if plastic mulch is not used.

• Grow seedlings in soil-less potting mixes or in sterilized or pasteurized soil.
• Treat seed with the recommended fungicide before planting.
• Maintain optimum plant growth and avoid injuring plants, as wounds provide a means of entry for the fungus.
• Where possible, avoid soil contact of fruit by using plastic mulch or by staking plants.
• Ensure crop residues decompose thoroughly before replanting an area.
• Applications of fungicides to the soil provide control of some diseases caused by R. solani.

Chemical control

Fumigation of plant beds will eradicate seedling pathogens, such as rhizoctonia solani; however, fumigated soil can become reinfected if pathogen-infested field soil is moved to fumigated areas.

Tomato pythium rot

Certain species of Pythium are capable of causing rot of numerous crops. Pythium rot, described as cottony leak or watery rot, occurs during wet weather or in poorly drained areas of fields. A common sight in vegetable gardens of all sizes, tomatoes (Lycopersicon spp.) are tender perennials that grow in U.S. Department of Agriculture plant hardiness zones 10 and 11, but are often grown as annuals throughout the world. Fungal diseases, such as Pythium, can attack these low-maintenance plants resulting in poor growth and fruit production, and root rot . However, with proper care you can prevent fungal pathogens from harming your tomato plants.

Causes

Pythium is a fungal pathogen found in the soil. It can attack tomato plants when they are overwatered, planted in diseased soil and when conditions are warm and humid. When the fruit touches infected soil or when water splashes infected soil onto the tomato, infection can occur. Certain species of Pythium also cause root rot.

Symptoms

Damping-off occurs at or before germination, causing rapid decline and death of seeds or young seedlings. On older plants, disease causes severe wilting and black stem, beginning at ground level, resulting in severe stunting or death of plants.

On fruit

Pythium generally starts as small, water soaked lesions on immature or mature fruit near or in contact with the soil. The whole fruit is involved within 72 hours, the epidermis is ruptured, and the fruit collapses. Under high moisture, a white, cottony growth may be apparent on the lesion surface.

Other parts

Seeds infected with this fungal pathogen typically won’t germinate and will decompose. Young seedlings may topple over and their stems develop mushy lesions. Water-soaked lesions appear on fruits infected with Pythium spp. and infected tissues, such as stems and roots, will begin to darken and become soft before rotting. Another sign of Pythium and root rot is a white mycelial growth with a cotton-like appearance forming on infected plant tissue. Some infected tomato plants may have stunted growth while others show few above ground symptoms.

Disease cycle

Pythium species can survive indefinitely in the soil on various organic substrates or as long-lived, thick-walled spores. When free moisture is available, sporangia and spores are produced. Fruit infection can be by means of vegetative mycelium, sporangia, or spores. The pathogen is capable of direct penetration, but wounds enhance infection. Highly succulent plants due to poor growing conditions, especially excessive nitrogen, are highly susceptible.

Control

Use a biofungicide containing the beneficial fungus Trichoderma harzianum, which works to suppress root pathogens. Apply it to newly sown seeds and transplants as a soil drench; can also be used on established plants. Avoid planting in poorly drained areas.

Cultural control

The best defense against Pythium and root rot is to implement cultural control and proper care for the tomato plants. Plant only disease-free seedlings in disease-free soils and use sterilized gardening equipment. Ensure the soil the tomatoes will grow in is well drained and avoid overwatering the plants. Overhead irrigation will dampen the leaves of the plant and increase the chance of fungal attacks. Instead, irrigate lower to the ground close to the base of the plant. Another option is to use plastic mulch around the tomato plants. This will prevent water from splashing soil onto the plant and causing the fungal pathogen to spread.

Chemical control

Fungicides containing fludioxonil, copper compounds and mefenoxam can control Pythium and root rot on tomato plants. These fungicides include pre-plant soil fumigant, soil drench applied during transplant and foliar sprays applied after the fungal disease infects the vegetable plants. The application ratio and instruction vary from one type of fungicide to another. For example, one brand of fungicide recommends spraying the infected tomato plants once every two to four weeks with a solution of 1/4 quart of the fungicide mixed with 5 gallons of water. Always follow the recommended directions found on the fungicide label of the specific brand you are using. This will increase its effectiveness and prevent unintended damage to the tomato plants.