Plant Disease Phenotype

Tomato mosaic virus (ToMV) is a member of family tobamoviridae and belongs to the genus tobamovirus, which is a plant pathogenic virus. It is found worldwide and affects tomatoes and many other wide host range plants including many agricultural crops and weeds such as tobacco and beans, all of which can serve as inoculum sources. The tomato crop is highly susceptible to the Tomato mosaic virus (ToMV). The symptoms vary from tiles, wrinkle, reduction and curvature of leaflets, and irregular ripening of fruits. This disease requires attention because of its easy dissemination by contact, cultural practices, or contaminated seed. Tomato mosaic virus symptoms can be found at any stage of growth and all parts of the plant may be infected. ToMV causes yellow mosaic symptoms on the leaves and tomato fruits. Tomato mosaic virus symptoms are seen as a general mottling or mosaic appearance on foliage. Light and darker green mosaic leaf mottle, sometimes with distortion of younger leaves; this is

Target spot on tomato fruit is difficult to recognize in the early stages, as the disease resembles several other fungal diseases of tomatoes. However, as diseased tomatoes ripen and turn from green to red, the fruit displays circular spots with concentric, target-like rings and a velvety black, fungal lesion in the center. The “targets” become pitted and larger as the tomato matures. Management Remove old plant debris at the end of the growing season; otherwise, the spores will travel from debris to newly planted tomatoes in the following growing season, thus beginning the disease anew. Dispose of the debris properly and don’t place it on your compost pile unless you’re sure your compost gets hot enough to kill the spores. Rotate crops and don’t plant tomatoes in areas where other disease-prone plants have been located in the past year – primarily eggplant, peppers, potatoes or, of course – tomatoes. Rutgers University Extension recommends a three-year rotation cycle to reduce soil-bo

The two-spotted spider mite is the most common mite species that attacks vegetable and fruit crops. Spider mites can occur in tomato, eggplant, potato, vine crops such as melons, cucumbers, and other crops. Two-spotted spider mites are one of the most important pests of eggplant. They have up to 20 generations per year and are favored by excess nitrogen and dry and dusty conditions. Outbreaks are often caused by the use of broad-spectrum insecticides which interfere with the numerous natural enemies that help to manage mite populations. As with most pests, catching the problem early will mean easier control. Feeding injury often gives the top leaf surfaces a mottled or speckled, dull appearance. Leaves then turn yellow and drop. Large populations produce visible webbing that can completely cover the leaves. In the field, spider mites are favored by hot dry weather, which also aggravates injury by stressing the plant. Damage is often underestimated since the wounds and the pest are not

Septoria leaf spot, also called Septoria blight, is a very common disease of tomatoes.1 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.  Septoria leaf spot is caused by a fungus, Septoria lycopersici. It is one of the most destructive diseases of tomato foliage and is particularly severe in areas where wet, humid weather persists for extended periods. Septoria leaf spot usually appears on the lower leaves after the first fruit sets. Spots are circular, about 1/16 to 1/4 inch in diameter with dark brown margins and tan to gray centers with small black fruiting structures. Characteristically, there are many spots per leaf. This disease spreads upwards from oldest

Leaf mold is a common fungal disease that affects tomatoes that are cultivated in especially humid environments. Feeding off of the humidity, the mold grows and thrives after attaching itself to the leaves of the tomato plant. Once the mold is noticed, immediate action is required to save the plant, otherwise the foliage will be compromised, which will reduce the amount of tomatoes your plants will yield. Fortunately for tomato growers, this fungal disease is relatively easy to treat and cure. The first signs of leaf mold are, as you might expect, on the leaves themselves, as the topside of the leaves start to develop small gray, yellow, white, or pale green patches. The underside of the leaves begin to develop a fuzzy texture and turn purple. Oftentimes, the fuzz will appear in an olive green color. The fuzzy texture is actually the spores of the mold fungus. The fruit of the tomato plant is rarely infected by leaf mold. As the disease progresses, the infected tissue of the leaves bec

Late blight is caused by the oomycete Phytophthora infestans. Oomycetes are fungus-like organisms also called water molds, but they are not true fungi. There are many different strains of P. infestans. These are called clonal lineages and designated by a number code (i.e. US-23). Many clonal lineages affect both tomato and potato, but some lineages are specific to one host or the other. The host range is typically limited to potato and tomato, but hairy nightshade (Solanum physalifolium) is a closely related weed that can readily become infected and may contribute to disease spread. Under ideal conditions, such as a greenhouse, petunia also may become infected. Phytophthora infestans can overwinter in Minnesota if protected in potato cull piles. Overwintering in a tomato production system is unlikely but infected tomato fruits may give rise to infected volunteer seedlings the following season. The most common routes of introduction each season are infected potato seed tubers, infected