| Rivellia | |
|---|---|
 | |
| Rivellia syngenesiae | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Diptera |
| Family: | Platystomatidae |
| Subfamily: | Platystomatinae |
| Genus: | Rivellia Robineau-Desvoidy, 1830 |
| Type species | |
| Rivellia herbarum Robineau-Desvoidy, 1830 | |
Rivellia is a genus of signal flies (insects in the family Platystomatidae). There are at least 140 described species in Rivellia. [1] [2] [3] [4]
There is limited information and understanding about the juvenile stages of most signal fly species. Thirteen species of Rivellia have, however, been studied in the field of agriculture because the larvae of many of these flies are associated with both living and decaying root nodules of nitrogen-fixing legumes, such as soybean, peanuts, and pigeon pea. They can also be found on the roots or flowers of other cultivated plants like eggplant, sorghum, black locust, and Narcissus. [5]
With soybean, this association has been shown to be economically significant because pest-induced stress caused by these flies can significantly reduce nitrogen fixation and yields; Rivellia quadrifasciata, Rivellia basilaris, and Rivellia basilaris are all known pests of root nodules of this crop. Because this is a widely distributed genus, economically important effects are likely to be found in many other crops world-wide. [5]
Rhizobia are diazotrophic bacteria that fix nitrogen after becoming established inside the root nodules of legumes (Fabaceae). To express genes for nitrogen fixation, rhizobia require a plant host; they cannot independently fix nitrogen. In general, they are gram negative, motile, non-sporulating rods.
A legume is a plant in the family Fabaceae, or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock forage and silage, and as soil-enhancing green manure. Well-known legumes include beans, soybeans, chickpeas, peanuts, lentils, lupins, grass peas, mesquite, carob, tamarind, alfalfa, and clover. Legumes produce a botanically unique type of fruit – a simple dry fruit that develops from a simple carpel and usually dehisces on two sides.
In agriculture, a green manure is a crop specifically cultivated to be incorporated into the soil while still green. Typically, the green manure's biomass is incorporated with a plow or disk, as is often done with (brown) manure. The primary goal is to add organic matter to the soil for its benefits. Green manuring is often used with legume crops to add nitrogen to the soil for following crops, especially in organic farming, but is also used in conventional farming.
Root nodules are found on the roots of plants, primarily legumes, that form a symbiosis with nitrogen-fixing bacteria. Under nitrogen-limiting conditions, capable plants form a symbiotic relationship with a host-specific strain of bacteria known as rhizobia. This process has evolved multiple times within the legumes, as well as in other species found within the Rosid clade. Legume crops include beans, peas, and soybeans.
The soybean cyst nematode (SCN), Heterodera glycines, is the most devastating pest to soybean crop yields in the U.S., targeting the roots of soybean and other legume plants. When infection is severe SCNs cause stunting, yellowing, impaired canopy development, and yield loss. The symptoms caused by SCNs can go easily unrecognized by farmers—in some cases there are no warning symptoms before a loss of 40% of the yield. Due to the slight stunting and yellowing, many farmers may mistake these symptoms as environmental problems when in fact they are SCNs. Another symptom of SCNs that may affect farmers' yields is stunted roots with fewer nitrogen-fixing nodules. Due to the fact that soybean cyst nematodes can only move a few centimeters in the soil by themselves, they mostly are spread via tillage or plant transplants. This area of infection will look patchy and nonuniform making diagnosis more difficult for farmers. They can be seen in the roots of summer soybean plants if the roots are taken out very carefully and gently washed with water. The egg masses should be seen as bright white or yellow "pearls" on the roots. The later the roots are pulled the harder it will be to diagnose due to the SCNs female dying and turning a much darker color, forming a "cyst". The best way to know if a field is infected by soybean cyst nematodes is to take a soil sample to a nematologist.
The Tephritoidea are a superfamily of flies. It has over 7,800 species, the majority of them in family Tephritidae.
The Platystomatidae are a distinctive family of flies (Diptera) in the superfamily Tephritoidea.
Bradyrhizobium is a genus of Gram-negative soil bacteria, many of which fix nitrogen. Nitrogen fixation is an important part of the nitrogen cycle. Plants cannot use atmospheric nitrogen (N2); they must use nitrogen compounds such as nitrates.
Platystomatinae is a subfamily of flies (Diptera) in the family Platystomatidae that includes 80 genera, the largest subfamily with at last estimate, c. 900 species globally.
Rivellia munda is a species of signal flies.
Rivellia cognata is a species of signal flies.
Rivellia winifredae is a species of signal flies. It is found associated with Apios americana.
Rivellia steyskali is a species of signal flies.
Rivellia quadrifasciata, the soybean nodule fly, is a species of signal flies. Larvae are known to feed on Glycine max, Phaseolus limensi, Vigna unguiculata, and Desmodium plants.
Rivellia micans is a species of signal flies.
Rivellia vaga is a species of signal flies.
Rivellia variabilis is a species of signal flies.
Rivellia coquilletti is a species of signal flies.
Rivellia inaequata is a species of signal flies.
Rivellia conjuncta is a species of signal flies.
| Authority control databases: National |
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