more... > Plant Diagnostic Center > Disease Image Gallery > Tomato Yellow Leaf Curl [Image: TYLCV on field-grown tomatoes] Tomato yellow leaf curl is a disease of tomatoes caused by the whitefly-transmitted virus, Tomato Yellow Leaf Curl Virus (TYLCV). This disease was first observed in Louisiana in 2000 and since then has occurred sporadically in both field- and greenhouse-grown tomatoes. After a plant becomes infected, new growth is severely stunted and fruit production ceases. Disease management relies on use of disease-free transplants, planting resistant varieties and controlling whiteflies. Mayhaw Diseases [Image: Fire blight on susceptible mayhaw] There are two major diseases that affect mayhaws in Louisiana. Diseases of Ferns [Image: Virus-affected Japanese holly fern] A new virus was recently described from nursery and landscape plantings of both Japanese holly and leatherleaf ferns. Diseases of Oaks [Image: Powdery mildew symptoms on upper surface of oak leaves.] Oaks, a dominant member of the landscape, are subject to a number of diseases.  more articles... Pumpkin Diseases [Image: Click here to view larger image] Pumpkin (Cucurbita pepo) is a warm-season vegetable that can be grown throughout much of the United States. Together with winter squash, pumpkins are among the most-resistant of the cucurbits to certain diseases and insect damage. However, diseases such as Phytophthora fruit rot, Microdochium blight, Zucchini yellow mosaic, Fusarium rot and gummy stem blight are several common diseases that can severely affect pumpkin production. Diseases of Peas and Beans [Image: USDA.] Beans and peas are commonly affected by many diseases. If proper cultural practices, such as seed certification, use of resistant varieties, proper planting and crop rotation are followed, many of these problems can be avoided. Pepper Diseases [Image: Click here to view larger image.] The pepper (Capsicum spp) originated in Mexico and surrounding areas of Central America. It is an excellent source of vitamin A, vitamin C and calcium. An important crop in commercial vegetable production, peppers have disease problems with which growers must be concerned. Cucumber Diseases [Image: Click here to view larger image.] Cucumber (Cucumis spp.), like other cucurbits (melons, squash, pumpkins, etc.), are attacked by several pathogens that can result in severe crop losses. Most damage is observed on cucumber leaves and stems. Fruits can also be severely affected, resulting in overall poor quality and yield, especially if disease has already weakened the plant. Mustard Diseases [Image: Click here to view larger image] Mustard (Brassica juncea ) is vulnerable to several diseases. The most serious ones include downy mildew, white rust, sclerotinia stalk rot (white mold), leaf spots and virus mosaic. Eggplant Diseases [Image: Click here to view larger image] Solanum melongena L. (eggplant) is a member of Solanaceae family. This is frost-tender herbaceous perennial, usually grown as an annual plant. Diseases such as Verticillium wilt, Southern blight, Phomopsis blight, Anthracnose fruit rot and Altenaria blight are commonly associated with eggplant and can reduce its harvestable yield significantly. Cabbage Diseases [Image: Click here to view larger image] Cabbage, broccoli, cauliflower, brussels sprouts and kale are some of the members of the crucifer family often referred to as cole crops. Several diseases are associated with these plants, including root and stem rots of young plants, black rot, downy mildew and viruses. Squash Diseases [Image: Click here to view larger image.] Like any other crop, squash is susceptible to a variety of diseases that attack below- and above-ground parts of the plant. Major squash diseases include gummy stem blight/black rot, scab, powdery mildew, nematodes and several viral diseases. Because many of the fungal, bacterial and nematode pathogens survive in soil and/or crop debris, crop rotation with non-cucurbit crops for at least three years is highly recommended. Herb Diseases [Image: Image courtesy of Dr. Gordon Holcomb, Louisiana State University. ] Herbs, whether annuals, biennials or perennials, are widely grown for their culinary, aromatic, medicinal and ornamental properties. The diversity of herbs grown is reflected by the diversity of diseases that occur on them. Diseases of Trees and Shrubs Trees and shrubs are important components of the landscape, providing structure, texture and color. A variety of plant health problems caused by biotic and abiotic agents greatly affect the quality of these plants. The use of best management practices is essential for the establishment and care of landscape trees and shrubs and the prevention of disease.