Texas root rot is a disease that is fairly common in Mexico and the southwestern United States resulting in sudden wilt and death of affected plants, usually during the warmer months. It is caused by a soil-borne fungus named Phymatotrichopsis omnivora that attacks the roots of susceptible plants. It was first discovered in 1888 by Pammel and later named by Duggar in 1916.
Fusarium wilt is a common vascular wilt fungal disease, exhibiting symptoms similar to Verticillium wilt. This disease has been investigated extensively since the early years of this century. The pathogen that causes Fusarium wilt is Fusarium oxysporum. The species is further divided into formae speciales based on host plant.
Northern root-knot nematode is a species of vegetable pathogens which produces tiny galls on around 550 crop and weed species. They invade root tissue after birth. Females are able to lay up to 1,000 eggs at a time in a large egg mass. By surviving harsh winters, they can survive in cold climates.
Radopholus similis is a species of nematode known commonly as the burrowing nematode. It is a parasite of plants, and it is a pest of many agricultural crops. It is an especially important pest of bananas and citrus, and it can be found on coconut, avocado, coffee, sugarcane, other grasses, and ornamentals. It is a migratory endoparasite of roots, causing lesions that form cankers. Infected plants experience malnutrition.
Powdery scab is a disease of potato tubers. It is caused by the cercozoan Spongospora subterranea f. sp. subterranea and is widespread in potato growing countries. Symptoms of powdery scab include small lesions in the early stages of the disease, progressing to raised pustules containing a powdery mass. These can eventually rupture within the tuber periderm. The powdery pustules contain resting spores that release anisokont zoospores to infect the root hairs of potatoes or tomatoes. Powdery scab is a cosmetic defect on tubers, which can result in the rejection of these potatoes. Potatoes which have been infected can be peeled to remove the infected skin and the remaining inside of the potato can be cooked and eaten.
Aphanomyces euteiches is a water mould, or oomycete, plant pathogen responsible for the disease Aphanomyces root rot. The species Aphanomyces euteiches can infect a variety of legumes. Symptoms of the disease can differ among hosts but generally include reduced root volume and function, leading to stunting and chlorotic foliage. Aphanomyces root rot is an important agricultural disease in the United States, Europe, Australia, New Zealand, and Japan. Management includes using resistant crop varieties and having good soil drainage, as well as testing soil for the pathogen to avoid infected fields.
Phytophthora nicotianae or black shank is an oomycete belonging to the order Peronosprales and family Peronosporaceae.
Rotylenchulus reniformis, the reniform nematode, is a species of parasitic nematode of plants with a worldwide distribution in the tropical and subtropical regions.
Rosellinia bunodes is a plant pathogen infecting several hosts including avocados, bananas, cacao and tea.
Pyrenochaeta terrestris is a fungal plant pathogen infecting maize, sweet potatoes and strawberries. This plant pathogen causes a disease in onion that is commonly called Pink Root. This fungus is also known to infect shallot, garlic, leek and chive, cantaloupe, carrot, cauliflower, corn, cowpea, cucumber, eggplant, lima bean, millet, vats, peas, peppers, potato, spinach, sugarcane and tomato.
Colletotrichum coccodes is a plant pathogen, which causes anthracnose on tomato and black dot disease of potato. Fungi survive on crop debris and disease emergence is favored by warm temperatures and wet weather.
Pratylenchus brachyurus is a plant parasitic nematode.
Paratylenchus hamatus, the fig pin nematode, is a species of migratory plant endoparasites, that causes lesions on plant roots resulting in symptoms of chlorosis, wilting and ultimately yield losses. They move and feed on different parts of host tissue throughout their life cycle in order to find enough susceptible host tissue to survive and reproduce. A wide range of host plant species are susceptible to the fig pin nematode, including many valuable fruit and vegetable crops such as figs, carrots and celery. They are also commonly found associated with woody perennials in California. P. hamatus inhabits soils in both Europe and North America, and was originally isolated from fig in central California in 1950.
Tobacco rattle virus (TRV) is a pathogenic plant virus. Over 400 species of plants from 50 families are susceptible to infection.
Pratylenchus is a genus of nematodes known commonly as lesion nematodes. They are parasitic on plants and are responsible for root lesion disease on many taxa of host plants in temperate regions around the world. Lesion nematodes are migratory endoparasites that feed and reproduce in the root and move around, unlike the cyst or root-knot nematodes, which may stay in one place. They usually only feed on the cortex of the root. Species are distinguished primarily by the morphology of the stylets.
Butte is a potato cultivar that was released in 1977.
Pratylenchus alleni is a migratory endoparasitic nematode, living inside of plant roots and feeding on parenchyma cells in the root cortex. P. alleni is an obligate biotroph, meaning it must have a living host in order to survive. Due to their incredibly broad host range, Pratylenchus species fall third in total economic impact, finishing just behind cyst nematodes and root knot nematodes (Meloidogyne). In Canada, it was isolated for the first time in 2011 in a soybean field.
Verticillium dry bubble, recently named Lecanicillium fungicola, is a mycoparasite that attacks white button mushrooms, among other hosts, during its generative period. L. fungicola infects the casing layer on the cap structure of several edible mushrooms. This fungal pathogen does not typically infect wild mushrooms, but more commonly cultivated mushrooms are infected such as A. bisporus, which are typically grown in large quantities. Severity of disease depends on several factors, including timing of infection and environmental conditions. Dry bubble follows the typical verticillium life cycle, although insect vectors play a large role in the spread of this disease. Control for L. fungicola is limited, and strict measures must be taken to prevent the spread of infection. L. fungicola is a devastating pathogen in the mushroom industry and causes significant losses in the commercial production of its main host A. bisporus. Annual costs for mushroom growers are estimated at 2–4% of total revenue.
Scutellonema bradys, also known as yam nematode, is a migratory endoparasitic nematode causing major damage to yam crop in many African tropical regions, as well in parts of South and Central America and Asia. They can cause reduction of 20-30% in tuber weight at harvest.
Botrytis squamosa is a fungus that causes leaf blight on onion that is distinctly characterized by the two stages – leaf spotting followed by blighting. The pathogen is an ascomycete that belongs to the family Sclerotiniaceae in the order Helotiales. The lesions start out as whitish streaks and take on a yellow tinge as they mature. They cause yield losses up to 30%. This fungus is endemic to the USA and has also been reported in Europe, Asia, and Australia. Typical management of this disease includes chemical fungicides with significant efforts being made to establish a means of biological control.
