Plant pathology is the scientific study of diseases in plants caused by pathogens and environmental conditions. Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like organisms, phytoplasmas, protozoa, nematodes and parasitic plants. Not included are ectoparasites like insects, mites, vertebrate, or other pests that affect plant health by eating plant tissues. Plant pathology also involves the study of pathogen identification, disease etiology, disease cycles, economic impact, plant disease epidemiology, plant disease resistance, how plant diseases affect humans and animals, pathosystem genetics, and management of plant diseases.
Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management role. It can be an important component of integrated pest management (IPM) programs.
Integrated pest management (IPM), also known as integrated pest control (IPC) is a broad-based approach that integrates both chemical and non-chemical practices for economic control of pests. IPM aims to suppress pest populations below the economic injury level (EIL). The UN's Food and Agriculture Organization defines IPM as "the careful consideration of all available pest control techniques and subsequent integration of appropriate measures that discourage the development of pest populations and keep pesticides and other interventions to levels that are economically justified and reduce or minimize risks to human health and the environment. IPM emphasizes the growth of a healthy crop with the least possible disruption to agro-ecosystems and encourages natural pest control mechanisms." Entomologists and ecologists have urged the adoption of IPM pest control since the 1970s. IPM allows for safer pest control.
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.
A leaf spot is a limited, discoloured, diseased area of a leaf that is caused by fungal, bacterial or viral plant diseases, or by injuries from nematodes, insects, environmental factors, toxicity or herbicides. These discoloured spots or lesions often have a centre of necrosis. Symptoms can overlap across causal agents, however differing signs and symptoms of certain pathogens can lead to the diagnosis of the type of leaf spot disease. Prolonged wet and humid conditions promote leaf spot disease and most pathogens are spread by wind, splashing rain or irrigation that carry the disease to other leaves.
A biopesticide is a biological substance or organism that damages, kills, or repels organisms seen as pests. Biological pest management intervention involves predatory, parasitic, or chemical relationships.
Athelia rolfsii is a corticioid fungus in the family Atheliaceae. It is a facultative plant pathogen and is the causal agent of "southern blight" disease in crops.
Colletotrichum acutatum is a plant pathogen and endophyte. It is the organism that causes the most destructive fungal disease, anthracnose, of lupin species worldwide. It also causes the disease postbloom fruit drop on many varieties of citrus, especially Valencia and navel oranges in Florida.
Monilinia laxa is a plant pathogen that is the causal agent of brown rot of stone fruits.
Meloidogyne arenaria is a species of plant pathogenic nematodes. This nematode is also known as the peanut root knot nematode. The word "Meloidogyne" is derived from two Greek words that mean "apple-shaped" and "female". The peanut root knot nematode, M. arenaria is one of the "major" Meloidogyne species because of its worldwide economic importance. M. arenaria is a predominant nematode species in the United States attacking peanut in Alabama, Florida, Georgia, and Texas. The most damaging nematode species for peanut in the USA is M. arenaria race 1 and losses can exceed 50% in severely infested fields. Among the several Meloidogyne species that have been characterized, M. arenaria is the most variable both morphologically and cytologically. In 1949, two races of this nematode had been identified, race 1 which reproduces on peanut and race 2 which cannot do so. However, in a recent study, three races were described. López-Pérez et al (2011) had also studied populations of M. arenaria race 2, which reproduces on tomato plants carrying the Mi gene and race 3, which reproduces on both resistant pepper and tomato.
Meloidogyne javanica is a species of plant-pathogenic nematodes. It is one of the tropical root-knot nematodes and a major agricultural pest in many countries. It has many hosts. Meloidogyne javanica reproduces by obligatory mitotic parthenogenesis (apomixis).
The California Department of Pesticide Regulation, also known as DPR or CDPR, is one of six boards and departments of the California Environmental Protection Agency (Cal/EPA).
The Western tarnished plant bug is a serious pest of cotton, strawberries, and seed crops such as alfalfa. In the state of California alone the bug causes US$30 million in damage to cotton plants each year, and at least US$40 million in losses to the state's strawberry industry.
Buckeye rot of tomato is caused by three species of pathogens in the genus Phytophthora: P. nicotianae var. parasitica, P. capsici, and P. drechsleri. It is an oomycete that thrives in warm, wet conditions and lives in the soil. It is characterized by a bull’s eye pattern of dark brown rotting on the tomato fruit, and affects fruit that is close to, or lying on the soil. The easiest management is to keep the plant out of contact with the soil, although other chemical methods can be very effective. This disease commonly occurs in the southeast and south central areas of the United States. The disease has affected a large portion of crop yield in the United States as well as India. The relatively small genome size of Phytophthora parasitica compared to Phytophthora infestans gives researchers the unique ability to further examine its ability to cause disease.
Stem rot is a disease caused by a fungus infection in the stem. Fungus that causes stem rot are in the Rhizoctonia, Fusarium or Pythium genera. Stem rot can readily infect crops that are in their vegetative or flowering stages. The disease can survive up to five years in the soil. Symptoms of stem rot includes staining of infected area, reduced crop yield and crop failure. The disease can be spread through the use of unfiltered water as well as unsterilized tools. Also leaving previous dead roots in soil can increase the risk of stem rot. Spores can also enter the plant through injured stem tissue on the plant including from insect attacks. The fungus impedes stem functions like transporting nutrients. It can cause water to leak through the lesions of stem tissue. Common infected crop plants are soybeans and potatoes. An issue with maintaining this disease is the lack of management by crop producers. Producers of soybeans tend to not manage for the disease because it is not normally yield limiting in a large area. Fungicides can be used to manage the disease as well as burning the crop after harvest or letting it decompose.
Agriculture is a significant sector in California's economy, producing nearly US$50 billion in revenue in 2018. There are more than 400 commodity crops grown across California, including a significant portion of all fruits, vegetables, and nuts for the United States. In 2017, there were 77,100 unique farms and ranches in the state, operating across 25.3 million acres of land. The average farm size was 328 acres (133 ha), significantly less than the average farm size in the U.S. of 444 acres (180 ha).
Mudaria luteileprosa, or the Durian seed borer is a species of moth in the family Noctuidae. It is found in Malaysia, Indonesia, and Thailand.
Strawberries in the United States are almost entirely grown in California – 86% of fresh and 98% of frozen in 2017 – with Florida a distant second. Of that 30.0% was from Monterey, 28.6% from Ventura, 20.0% from Santa Barbara, 10.0% from San Luis Obispo, and 9.2% from Santa Cruz. The Watsonville/Salinas strawberry zone in Santa Cruz/Monterey, and the Oxnard zone in Ventura, contribute heavily to those concentrations.
