| Fusarium oxysporum f.sp. quitoense | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Fungi |
| Division: | Ascomycota |
| Class: | Sordariomycetes |
| Order: | Hypocreales |
| Family: | Nectriaceae |
| Genus: | Fusarium |
| Species: | F. oxysporum |
| Forma specialis: | F. o. f.sp. quitoense |
| Trionomial name | |
| Fusarium oxysporum f.sp. quitoense | |
Vascular wilt in the perennial shrub lulo or naranjilla ( Solanum quitoense ) is a disease caused by the fungus Fusarium oxysporum f. sp. quitoense. [1]
Lulo or naranjilla ( Solanum quitoense ) is a perennial shrub whose fruit is an important input for production of fresh juice in Colombia, Ecuador, and other Latin American countries. [1] [2] Lulo is highly profitable for small-scale farmers and its production reached more than 3800 ha in Colombia in 2013 and 5000 ha in Ecuador in 2010. [3] [4] [5] This crop has been considered as very promising for export markets since the 1970s but problems of low productivity and susceptibility to many diseases have limited its potential. [1]
Diseased plants are easily distinguishable due to their flaccid and chlorotic appearance. Flaccidity and chlorosis start in the lower regions of the plant and progressively move upwards causing wilt of the entire plant. [6] In later stages of disease development, progressive defoliation occurs, which is followed by necrosis in leaves. Discoloration of the vascular system is a characteristic symptom. Vascular discoloration, ring shaped brown coloration of the phloem, is visible as the vascular system becomes exposed following leaf and flower abscission in defoliation. [6] Vascular discoloration is clearly observed when longitudinal or transverse cuts are made on the main roots, stems, leaf petioles, fruit peduncles, and fruits. [6]
Vascular wilt has a huge impact on crop yield. Some regions in Ecuador can reach up to 80% in yield losses for Lulo production due to vascular wilt. [6] [7] [8] This reduced yield is very problematic since many small communities depends economically mostly on this crop and resources for diseases management at these areas are not available,. [6] [7] But this disease not only has an economic impact, environmental problems also are derived from this problematic in the form of deforestation. [1]
Deforestation is often associated with Lulo cultivation because farmers generally abandoned the land once the disease shows and move to other areas that are pathogen free which are often natural forest areas. [4] The lack of knowledge that this disease can be seed transmitted and combining it with the fact that moving to free-pathogen areas is a common practice to avoid disease leads to more deforestation. [4] In Ecuador this deforestation is a major concern because the Amazon region, where most Lulo is produced, is considered a biodiversity “hotspot”. [4]
Data collected in several commercial farms located at the Pastaza Province, Amazon region of Ecuador, determine that the incidence of this disease in a period between October 2017 and January 2018 was around of 17%, observing that the variety naranjilla común was the most susceptible. [9] [8] This problematic increases as time goes on due to the poor availability of information for farmers regarding management practices.
There are many factors that play an important role for the spread a Fusarium species in the fields. In the case of vascular wilt in Lulo there is two major factors that make this disease an epidemic problem in Ecuador and Colombia. [6] [4] Primarily this pathogen benefits from the combination of the cultural practices and from the fact that it is seed transmitted for spread itself. In Ecuador, Lulo seed is produced informally, farmers get their seeds from selected ripe fruits, and plants are produced in improvised seed beds near naranjilla plots. [10] Since it is a seed-borne pathogen and because there is no initiative to produce a pathogen-free seed then is very easy to spread the disease and cause epidemics. [10] Also, this pathogen as a species is a soil-borne pathogen which means that it can persist in the soil for many years. [6] [7] [4] Another factor that benefits the presence vascular wilt in Lulo is the presence of the nematode Meloidogyne incognita which increases the plant's susceptibility to infection from F. oxysporum f. sp. quitoense probably due to lesions on the root surface. [4]
Primarily, the lack of management strategies is the main reason that this disease cause epidemics in Latin America. In Ecuador, the IPM CRSP began the development of management strategies for the control of this disease. The project pursued two management strategies: (1) use of pathogen-free seeds; and (2) development of naranjilla varieties with genetic resistance. [4] The production of certified disease-free seed is not practical in naranjilla growing areas where producers are wide spread and access by seed suppliers is limited. Chemical control took place for disease control. [4] Laboratory testing with chemical alternatives determined that the use of carbendazim in 2g/L of water provides a good control of the pathogen in the seed and was the most cost effective. [7] [4] An Instituto Nacional de Investigaciones Agropecuarias de Ecuador (INIAP) bulletin and other outreach materials were developed to help the information to be spread to the farmers. [4] [1] For the production of resistant varieties of Lulo, several accessions of the Lasiocarpa section genus Solanum were found to be resistant to F. oxysporum f. sp. quitoense. [1] The development of the resistant varieties focused on the use of plant grafting. An experiment found that grafting common Lulo cultivar “nanegalito” with the accession ECU-6242 of Solanum hirtum provided the best result for getting better yields. One interesting fact is that ECU-6242 is resistant to the root knot nematode (Meloidogyne incognita) which also helps the disease to develop. [4] [1] In Nariño Department, Colombia, researchers have also found that grafting S. hirtum with S. quitoense is a good way to improve the plants resistance to infections of F. oxysporum without losing fruit quality. [11]
Fusarium oxysporum, an ascomycete fungus, comprises all the species, varieties and forms recognized by Wollenweber and Reinking within an infrageneric grouping called section Elegans. It is part of the family Nectriaceae.
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.
Panama disease is a plant disease that infects banana plants. It is a wilting disease caused by the fungus Fusarium oxysporum f. sp. cubense (Foc). The pathogen is resistant to fungicides and its control is limited to phytosanitary measures.
Solanum quitoense, known as naranjilla in Ecuador, Costa Rica, and Panama and as lulo in Colombia, is a tropical perennial plant from northwestern South America. The specific name for this species of nightshade means "from Quito."
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Nufar basil is the first variety of sweet basil that is resistant to fusarium wilt. Fusarium wilt is a disease that causes sudden wilting and death in multiple species, including basil. It is caused by the fungus Fusarium oxysporum f. sp. basilicum, which attacks the xylem in the stem, blocking water uptake and leading to a characteristic sudden leaf wilt that does not respond to watering. Nufar basil is resistant to fusarium wilt, remaining asymptomatic even when infected. It was released in 1999 in Israel by the breeders of the Agricultural Research Organization, and commercialized by Genesis Seeds.
Ceratocystis paradoxa or Black Rot of Pineapple is a plant pathogen that is a fungus, part of the phylum Ascomycota. It is characterized as the teleomorph or sexual reproduction stage of infection. This stage contains ascocarps, or sacs/fruiting bodies, which contain the sexually produced inoculating ascospores. These are the structures which are used primarily to survive long periods of time or overwinter to prepare for the next growing season of its host. Unfortunately, the sexual stage is not often seen in the natural field but instead the anamorph, or asexual stage is more commonly seen. This asexual stage name is Thielaviopsis paradoxa and is the common cause of Black rot or stem-end rot of its hosts.
Fusarium oxysporum f.sp. betae is a destructive fungal plant pathogen. It causes Fusarium yellows or fusarium wilt, characterized by yellowing and dwarfing.
Fusarium oxysporum f.sp. carthami is a fungal plant pathogen.
Fusarium oxysporum f.sp. ciceris is a fungal plant pathogen that causes fusarium wilt of chickpea.
Fusarium redolens is a species of fungus in the genus Fusarium and family Nectriaceae. This species is a soil-borne plant pathogen in temperate prairies. It causes diseases such as root, crown, and spear rot, seedling damping-off, and wilting disease. It is a known producer of the alkaloids peimisine and imperialine-3β-d-glucoside, which has implications for traditional Chinese medicine.
Phialophora gregata is a Deuteromycete fungus that is a plant pathogen which causes the disease commonly known as brown stem rot of soybean. P. gregata does not produce survival structures, but has the ability to overwinter as mycelium in decaying soybean residue.
A wilt disease is any number of diseases that affect the vascular system of plants. Attacks by fungi, bacteria, and nematodes can cause rapid killing of plants, large tree branches or even entire trees.
Solanum pseudolulo is a subtropical perennial plant from northwestern South America. The pseudolulo is a large herbaceous plant or a small shrub, with heart-shaped leaves. The leaves and stems of the plant are covered in short hairs, and the entire plant is often covered in sharp spines.
Black rot, caused by the bacterium Xanthomonas campestris pv. campestris (Xcc), is considered the most important and most destructive disease of crucifers, infecting all cultivated varieties of brassicas worldwide. This disease was first described by botanist and entomologist Harrison Garman in Lexington, Kentucky, US in 1889. Since then, it has been found in nearly every country in which vegetable brassicas are commercially cultivated.
Fusarium oxysporum f. sp. cubense is a fungal plant pathogen that causes Panama disease of banana, also known as Fusarium wilt. The fungi and the related disease are responsible for widespread pressure on banana growing regions, destroying the economic viability of several commercially important banana varieties.
Solanum caripense is a species of evergreen shrub native to South America and grown for its edible fruit.
Bayoud disease is an epiphytic fungal disease of date palm. The pathogen responsible for the disease is Fusarium oxysporum f.sp. albedinis.
Koa wilt is a relatively new disease to Hawaii, discovered in 1980. Koa wilt is caused by a forma specialis of the fungus Fusarium oxysporum, which is now abundant in Hawaiian soils and infects the native Acacia koa tree, a once-dominant species in the canopy of Hawaiian forests. Fusarium oxysporum f.sp. koae is believed to have been brought into Hawaii on an ornamental acacia plant. Fusarium fungi clog the tree xylem, causing significant wilt and mortality among Koa trees. Due to their cultural importance, Koa wilt is one of the Envirormental issues of Hawaii.
Coffee wilt disease (tracheomycosis) is a common wilt that results in complete death of coffee trees it infects. This vascular disease is induced by the fungal pathogen known by its teleomorph Gibberella xylarioides. In 1927, coffee wilt disease (CWD) was first observed in the Central African Republic where it developed slowly and went on to cause two epidemics between the 1930s and the 1960s. Coffee wilt disease was first seen in Coffea excelsa.
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