| Rice weevil | |
|---|---|
 | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Coleoptera |
| Infraorder: | Cucujiformia |
| Family: | Curculionidae |
| Subfamily: | Dryophthorinae |
| Tribe: | Litosomini |
| Genus: | Sitophilus |
| Species: | S. oryzae |
| Binomial name | |
| Sitophilus oryzae | |
| Synonyms | |
| |
The rice weevil (Sitophilus oryzae) is a stored product pest which attacks seeds of several crops, including wheat, rice, and maize.
The adults are usually between 3 and 4.6 mm long, with a long snout. The body color appears to be brown/black, but on close examination, four orange/red spots are arranged in a cross on the wing covers. It is easily confused with the similar looking maize weevil. The maize weevil is typically somewhat larger than the rice weevil, but rice weevils as large as the largest maize weevils and maize weevils nearly as small as the smallest rice weevils have been found. Some external features can be used to differentiate the vast majority of adults, but the only reliable features are on the genitalia (see table below). Both species can hybridize. The genitalic structure of hybrids is unknown. [2] [3] [4] [5]
| Rice weevil (S. oryzae) | Maize weevil (S. zeamais) |
|---|---|
 |  |
 |  |
| Longitudinally elliptical punctures on pronotal dorsum | Punctures on pronotal dorsum typically nearly circular, rarely elliptical |
| Pronotal punctures are separated by a flat, median, longitudinal puncture-free zone | Pronotal punctures are nearly equally spaced apart, and pronotum typically has no median puncture-free area (rarely has a narrow puncture-free median zone) |
| Less than 20 pronotal punctures along the approximate midline, running from neck to scutellum | More than 20 pronotal punctures along the approximate midline, running from neck to scutellum (not reliable for individuals not reared on corn, which are typically smaller) |
| Scutellar elevations typically closer together compare to their longitudinal length | Scutellar elevations typically farther apart compared to their longitudinal length |
| Scutellar elevations typically extend longitudinally approximately more than halfway down the scutellum | Scutellar elevations typically extend longitudinally approximately halfway down the scutellum |
| Proepimera meets behind the fore coxae and along the posterior edge, has a distinct notch along the posterior edge at the site of the meeting point | Proepimera meets behind the fore coxae and has a barely discernible notch along the posterior edge at the site of the meeting point |
| Male aedeagus is smooth and shiny on the dorsal surface | Male aedeagus has two dorsal, longitudinal grooves |
| Epipharyngeal rods of larvae have virtually the same width throughout | Epipharyngeal rods of larvae tapering apically |
| Lateral lobes of Y-shaped sclerite of female genitalia not tapering and rounded at apex | Lateral lobes of Y-shaped sclerite of female genitalia tapering and pointed at apex |
| Fewer than five sensory organs at the tip of the labial palps of larvae | More than five sensory organs at the tip of the labial palps of larvae |
Adult rice weevils are able to fly, [6] and can live for up to two years. Females lay 2–6 eggs per day and up to 300 over their lifetime. The female uses strong mandibles to chew a hole into a grain kernel after which she deposits a single egg within the hole, sealing it with secretions from her ovipositor. The larva develops within the grain, hollowing it out while feeding. It then pupates within the grain kernel and emerges 2–4 days after eclosion.
Male S. oryzae produce an aggregation pheromone called sitophilure ((4S,5R)-5-Hydroxy-4-methylheptan-3-one) to which males and females are drawn. A synthetic version is available which attracts rice weevils, maize weevils and grain weevils. Females produce a pheromone which attracts only males.
Its gammaproteobacterial symbiont Candidatus Sodalis pierantonius str. SOPE is able to supply rice weevil with essential vitamins like pantothenic acid, riboflavin, and biotin. [7] During larvae development, bacteria rely on up-regulation of type three secretion system genes and genes for flagellum so they can infect insect stem cells. [8]
Control of weevils involves locating and removing all potentially infested food sources. Rice weevils in all stages of development can be killed by freezing infested food below −18 °C (0 °F) for a period of three days, or heating to 60 °C (140 °F) for a period of 15 minutes. [9]
A pheromone is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavior of the receiving individuals. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology.
The Curculionidae are a family of weevils, commonly called snout beetles or true weevils. They are one of the largest animal families with 6,800 genera and 83,000 species described worldwide. They are the sister group to the family Brentidae.
Weevils are beetles belonging to the superfamily Curculionoidea, known for their elongated snouts. They are usually small – less than 6 mm in length – and herbivorous. Approximately 97,000 species of weevils are known. They belong to several families, with most of them in the family Curculionidae. It also includes bark beetles, which while morphologically dissimilar to other weevils in lacking the distinctive snout, is a subfamily of Curculionidae. Some other beetles, although not closely related, bear the name "weevil", such as the biscuit weevil, which belongs to the family Ptinidae.
Helicoverpa zea, commonly known as the corn earworm, is a species in the family Noctuidae. The larva of the moth Helicoverpa zea is a major agricultural pest. Since it is polyphagous during the larval stage, the species has been given many different common names, including the cotton bollworm and the tomato fruitworm. It also consumes a wide variety of other crops.
Sitophilus is a genus of weevils in the tribe Litosomini. Some species are familiar as pests of stored grain, nut, or seed. Notable pest species include the rice weevil, wheat weevil, and maize weevil.
The Indianmeal moth, also spelled Indian meal moth and Indian-meal moth, is a pyraloid moth of the family Pyralidae. Alternative common names are weevil moth, pantry moth, flour moth or grain moth. The almond moth and the raisin moth are commonly confused with the Indian-meal moth due to similar food sources and appearance. The species was named for feeding on Indian meal or cornmeal, and does not occur natively in India. It is also not to be confused with the Mediterranean flour moth, another common pest of stored grains.
The wheat weevil, also known as the grain weevil or granary weevil, is an insect that feeds on cereal grains, and is a common pest in many places. It can cause significant damage to harvested stored grains and may drastically decrease crop yields. The females lay many eggs and the larvae eat the inside of the grain kernels.
The khapra beetle, also called cabinet beetle, which originated in South Asia, is one of the world's most destructive pests of grain products and seeds. It is considered one of the 100 worst invasive species in the world. Infestations are difficult to control because of the insect's ability to survive without food for long periods, its preference for dry conditions and low-moisture food, and its resistance to many insecticides. There is a federal quarantine restricting the importation of rice into the U.S. from countries with known infestations of the beetle. Khapra beetle infestation can spoil otherwise valuable trade goods and threaten significant economic losses if introduced to a new area. Handling or consuming contaminated grain and seed products can lead to health issues such as skin irritation and gastrointestinal distress.
The Mediterranean flour moth or mill moth is a moth of the family Pyralidae. It is a common pest of cereal grains, especially flour. This moth is found throughout the world, especially in countries with temperate climates. It prefers warm temperatures for more rapid development, but it can survive a wide range of temperatures.
The European corn borer, also known as the European corn worm or European high-flyer, is a moth of the family Crambidae. It is a pest of grain, particularly maize. The insect is native to Europe, originally infesting varieties of millet, including broom corn. The European corn borer was first reported in North America in 1917 in Massachusetts, but was probably introduced from Europe several years earlier. Since its initial discovery in the Americas, the insect has spread into Canada and westwards across the United States to the Rocky Mountains.
Home-stored product entomology is the study of insects which infest foodstuffs stored in the home. It deals with the prevention, detection and eradication of the pests. The five major categories of insects considered in this article are flour beetles, the drugstore beetle, the sawtoothed grain beetle, the Indianmeal moth and fruit flies.
Rhyzopertha is a monotypic genus of beetles in the family Bostrichidae, the false powderpost beetles. The sole species, Rhyzopertha dominica, is known commonly as the lesser grain borer, American wheat weevil, Australian wheat weevil, and stored grain borer. It is a beetle commonly found within store bought products and pest of stored cereal grains located worldwide. It is also a major pest of peanuts. The first documentation of wheat infestation by R. dominica was observed in Australia. R. dominica are usually reddish brown to dark brown in coloration, vary in sizes, elongated and cylindrical.
The Angoumois grain moth is a species of the Gelechiidae moth family, commonly referred to as the "rice grain moth". It is most abundant in the temperate or tropical climates of India, China, South Africa, Indonesia, Malaysia, Japan, Egypt and Nigeria, with its location of origin being currently unknown. It is most commonly associated as a pest of field and stored cereal grains as they burrow within the kernel grains of crop plants, rendering them unusable for human consumption. By laying eggs between the grains themselves and hatching at a later time, often during the processing, transportation or storage stages, the moth can be transported to households or countries presently free of Angoumois grain moth infestations. Thus, constant protection against the Angoumois grain moth is required for grain up till the time of consumption.
The maize weevil, known in the United States as the greater rice weevil, is a species of beetle in the family Curculionidae. It can be found in numerous tropical areas around the world, and in the United States, and is a major pest of maize. This species attacks both standing crops and stored cereal products, including wheat, rice, sorghum, oats, barley, rye, buckwheat, peas, and cottonseed. The maize weevil also infests other types of stored, processed cereal products such as pasta, cassava, and various coarse, milled grains. It has even been known to attack fruit while in storage, such as apples.
Liposcelis bostrychophila is a species of booklouse in the family Liposcelididae. It is known nearly worldwide as a common pest of stored products. It is especially prevalent in cereals. In 2019 it was identified as a predator of mosquito eggs in a FAO/IAEA Insect Pest Control Laboratory which developed sterile males.
Prostephanus truncatus is commonly referred to as larger grain bore (LGB) with reference to the related Rhyzopertha dominica, another insect, which is relatively smaller in length, hence is referred to as the lesser grain bore. P. truncatus is about 6 mm (0.24 in) long as compared to 3 mm (0.12 in) long in Rh. dominica. At optimum conditions of 80% relative humidity and 32 °C (90 °F), and available food, P. truncatus completes its lifecycle within 27 days. It is a serious pest of dried grains, especially maize and dried cassava in West Africa. This beetle is believed to have been introduced into West Africa through food aid from America. It reached Africa through Tanzania in the early 1970s.
A storage pest is an insect or other animal that damages or destroys stored food or other stored valuable organic matter. Insects are a large proportion of storage pests with each type of crop having specific insects that gravitate towards them such as the genus Tribolium that consists of insects such as Tribolium castaneum or Tribolium confusum which damage flour crops primarily.
Diocalandra frumenti, commonly known as the palm weevil borer, the lesser coconut weevil, or four-spotted coconut weevil, is a species of weevil in the family Curculionidae. It occurs in Africa, Southern Asia and Northern Australia, and is a pest of coconut and other palm trees.
Cephalonomia tarsalis is a idiobiont ectoparasitoid hymenopteran in the family Bethylidae. Known hosts include: Oryzaephilus surinamensis, Sitophilus granarius, Sitophilus oryzae, Sitophilus zeamais, and Tribolium castaneum.
| Authority control databases: National |
|---|
