Fungus gnats are small, dark, short-lived gnats, of the families Sciaridae, Diadocidiidae, Ditomyiidae, Keroplatidae, Bolitophilidae, and Mycetophilidae (order Diptera); they comprise six of the seven families placed in the superfamily Sciaroidea.
Fungus gnats are small, dark, short-lived gnats, of the families Sciaridae, Diadocidiidae, Ditomyiidae, Keroplatidae, Bolitophilidae, and Mycetophilidae (order Diptera); they comprise six of the seven families placed in the superfamily Sciaroidea.
The larvae of most species feed on fungi growing on soil, helping in the decomposition of organic matter. However some species are predatory, including those in the genus Arachnocampa of family Keroplatidae – the "glowworms" of Australia and New Zealand. [1]
The adults are 2–8 millimetres (0.08–0.3 in) long, and are occasionally pollinators of plants and carriers of mushroom spores. [2] They also may carry diseases such as pythium (which causes "damping-off" to kill seedlings) on their feet. [3]
Most fungus gnats are weak fliers, and can often be seen walking rapidly over plants and soil, rather than flying. However, when airborne, the gnats may be quite annoying to humans by flying into their faces, eyes, and noses, both indoors and outdoors. [4] [5] These flies are sometimes confused with drain flies. [6]
This species goes through 4 stages of life: egg, larva, pupa, and adult. [7] The adults can live up to 10 days and lay up to 200-300 eggs [8] at a time in the moist top layer of the soil. These eggs will typically hatch within 4 days and progress through the cycle. The pupa stage also consists of about 4 days, then adult gnats emerge and begin the whole process again. [9]
Some fungus gnats are exceptionally hardy, being able to tolerate cold conditions through their possession of antifreeze proteins. Typically, overwintering organisms can either avoid freezing or tolerate freezing, but Excechia nugatoria can do both. For E. nugatoria, the production of noncolligative antifreeze proteins (NAPs) protects the head and thorax from freezing, but they do not protect the abdomen. Freezing of the head and thorax in other insects tends to have adverse effects on neural tissue, so it is not surprising that these protective mechanisms have been observed in certain species, but E. nugatoria is the only insect known to semi-freeze through the winter. By allowing the abdomen to freeze, evaporative water loss is reduced over the course of the winter. [10] [11]
Fungus gnats in the family Sciaridae may be pests. They are typically harmless to healthy plants - and humans - but can inflict extensive damage to seedlings; their presence can indicate more serious problems. In houseplants, the presence of sciarids may indicate overwatering; they may be feeding on roots that have been immersed in water too long and are thus rotting, or the gnats may be attracted to fungus growing in saturated topsoil. Consequently, allowing the top two inches of soil [12] to dry may reduce their numbers. [13] The pests are sometimes also managed by placing a layer of sand [14] [15] pebbles, [16] or indoor mulch on top of the soil around plants.
Pyrethrins and the similar pyrethroid compounds are known to have insecticidal properties, including against fungus gnats. [17] Related pyrethroid insectides have also been used. Pyrethrin compounds are known to occur in certain chrysanthemum flowers.
Commercial greenhouses typically employ the insect growth regulator diflubenzuron for control of fungus gnats and their larvae. It is applied to infected soil and will kill fungus gnat larvae for 30–60 days from a single application. Its mechanism of action is to interfere with chitin production and deposition and it also triggers insect larvae to molt early without a properly formed exoskeleton, resulting in the death of the larvae. Although it is targeted at fungus gnat larvae, care should be taken in applying it as it is highly toxic to aquatic invertebrates. Diflubenzuron typically has no toxic effect on adults; only the larvae are affected. [18] [19]
Various methods of controlling or eliminating fungus gnats with biological pest control have been developed. For example, Bacillus thuringiensis israelensis (BTI) is known to produce proteins that can kill fungus gnats larvae and some other insects like mosquitos. [20] [21] [22] [17] BTI is a naturally occurring bacteria that has been used for decades—the United States EPA reports that it has no toxicity to humans. [20] Several dozen products containing BTI have been approved for residential, commercial, and agricultural use in the United States. [20] The israelensis subspecies is suggested because other types of Bacillus thuriniensis (BT), such as those for controlling caterpillars, are ineffective at controlling fungus gnats. [17]
Steinernema nematodes have been used to control fungus gnats, including in combination with BTI. [17] [22] These nematodes, including the feltiae species, are parasites that can attack the larvae stage of fungus gnats. [23]
Mites of the species Stratiolaelaps scimitus (formerly known as "Hypoaspis miles") have also been shown to be effective at controlling fungus gnats . [17] These scimitus mites are a natural predator that eat fungus gnat eggs and small larvae.
Other methods for controlling fungus gnats include drenching the soil annually in an insecticidal soap. Hydrogen peroxide can be mixed with water and used to kill fungus gnat larvae in infected soil with a mixture of one part 3% hydrogen peroxide mixed with four parts water, then applied to the soil. [5] [6] Adults can be trapped with sticky traps made of yellow card stock or heavy paper coated in an adhesive since the adults are attracted to the color yellow. [24] [25]
Since the gnats are weak fliers, fan-based traps as well as other fly-killing devices may be used to help control free-flying gnats, especially indoors. There are a number of toxic and non-toxic methods of controlling sciarids and their larvae, including diatomaceous earth, powdered cinnamon, [5] or by placing smells they dislike around the plant such as dryer sheets or oils like lavender and peppermint. [26]
To investigate how bad the infestation possibly is, one can place cut-up pieces of potato onto the topsoil, and let them sit for about 72 hours. [27] The larvae will begin to feed on them within the week. Check every few days, pulling out larvae-covered potato pieces. [28]
Insecticides are pesticides used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by consumers. Insecticides are claimed to be a major factor behind the increase in the 20th-century's agricultural productivity. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans and/or animals; some become concentrated as they spread along the food chain.
Bacillus thuringiensis serotype israelensis (Bti) is a group of bacteria used as biological control agents for larvae stages of certain dipterans. Bti produces toxins which are effective in killing various species of mosquitoes, fungus gnats, and blackflies, while having almost no effect on other organisms. The major advantage of B. thuringiensis products is that they are thought to affect few non-target species. However, even though Bti may have minimal direct effects on non-target organisms, it may potentially be associated with knock-on effects on food webs and other ecosystem properties, including biodiversity and ecosystem functioning.
The pyrethrins are a class of organic compounds normally derived from Chrysanthemum cinerariifolium that have potent insecticidal activity by targeting the nervous systems of insects. Pyrethrin naturally occurs in chrysanthemum flowers and is often considered an organic insecticide when it is not combined with piperonyl butoxide or other synthetic adjuvants. Their insecticidal and insect-repellent properties have been known and used for thousands of years.
Leptoconops torrens is a species of small biting flies in the no-see-um family Ceratopogonidae. They were first mentioned in writing by Charles Henry Tyler Townsend in 1893. The name Leptoconops carteri is a junior synonym of L. torrens. They are prevalent in the southwestern and southeastern areas of the United States. In early stages of life, L. torrens flies dwell in soil, then emerge to feed and breed as fully developed adults.
The small hive beetle is a beekeeping pest. It is native to sub-Saharan Africa, but has spread to many other regions, including North America, Australia, and the Philippines.
In agriculture and gardening, a beneficial organism is any organism that benefits the growing process, including insects, arachnids, other animals, plants, bacteria, fungi, viruses, and nematodes. Benefits include pest control, pollination, and maintenance of soil health. The opposite of beneficial organisms are pests, which are organisms deemed detrimental to the growing process. There are many different types of beneficial organisms as well as beneficial microorganisms. Also, microorganisms have things like salt and sugar in them. Beneficial organisms include but are not limited to: Birds, Bears, Nematodes, Insects, Arachnids, and fungi. The ways that birds and bears are considered beneficial is mainly because they consume seeds from plant and spread them through feces. Birds also prey on certain insects that eat plants and hinder them from growing these insects are known as non beneficial organisms. Nematodes are considered beneficial because they will help compost and provide nutrients for the soil the plants are growing in. Insects and arachnids help the growing process because they prey on non beneficial organisms that consume plants for food. Fungi help the growing process by using long threads of mycelium that can reach very long distances away from the tree or plant and bring water and nutrients back to the tree or plant roots.
Mosquito control manages the population of mosquitoes to reduce their damage to human health, economies, and enjoyment. Mosquito control is a vital public-health practice throughout the world and especially in the tropics because mosquitoes spread many diseases, such as malaria and the Zika virus.
The Nematocera are a suborder of elongated flies with thin, segmented antennae and mostly aquatic larvae. This group is paraphyletic and contains all flies but species from suborder Brachycera, which includes more commonly known species such as the housefly or the common fruit fly. The equivalent clade to Nematocera is the whole Diptera, with Brachycera as a subclade. Families in Nematocera include mosquitoes, crane flies, gnats, black flies, and multiple families commonly known as midges. The Nematocera typically have fairly long, fine, finely-jointed antennae. In many species, such as most mosquitoes, the female antennae are more or less threadlike, but the males have spectacularly plumose antennae.
A larvicide is an insecticide that is specifically targeted against the larval life stage of an insect. Their most common use is against mosquitoes. Larvicides may be contact poisons, stomach poisons, growth regulators, or (increasingly) biological control agents.
Mycetophilidae is a family of small flies, forming the bulk of those species known as fungus gnats. About 3000 described species are placed in 150 genera, but the true number of species is undoubtedly much higher. They are generally found in the damp habitats favoured by their host fungi and sometimes form dense swarms.
The Sciaridae are a family of flies, commonly known as dark-winged fungus gnats. Commonly found in moist environments, they are known to be a pest of mushroom farms and are commonly found in household plant pots. This is one of the least studied of the large Diptera families, probably due to the small size of these insects and the similarity among species.
Tineola bisselliella, known as the common clothes moth, webbing clothes moth, or simply clothing moth, is a species of fungus moth. It is the type species of its genus Tineola and was first described by the Swedish entomologist Arvid David Hummel in 1823. The specific name is commonly misspelled biselliella – for example by G. A. W. Herrich-Schäffer, when he established Tineola in 1853.
Hylobius abietis or the large pine weevil is a beetle belonging to family Curculionidae. This species is widely regarded as the most important pest of most commercially important coniferous trees in European plantations. Seedlings planted or arising from natural regeneration after clear felling operations are especially at risk. The adult weevils cause damage by eating the bark of seedlings around the 'collar' of the stem, thus 'ring-barking' the tree seedling which usually results in its demise.
Delia flies are members of the Anthomyiidae family within the superfamily Muscoidae. The identification of different species of Delia can be very difficult for non-specialists as the diagnostic characteristics used for immature and/or female specimens may be inconsistent between species. Past taxonomic keys were not as comprehensive in their identification of Delia specimens; they were either too reliant on genetic characteristics, focused solely on a specific life stage, or were focused only on certain species. However current taxonomic keys aim to be more thorough by not only including morphological diagnostics for males, females, and immature specimens of various species, but also their genetic make-up or molecular barcode.
Stratiolaelaps scimitus is a small (0.5 mm) light brown mite that lives in the top 1⁄2 inch (13 mm) layer of soil. As a natural predator of fungus gnat pupae and of the snail parasite Riccardoella limacum it is used by gardeners and snail breeders for biological pest control. Stratiolaelaps scimitus is also commonly used by reptile, amphibian and invertebrate keepers as a preventative or reactive measure against grain mites and reptile mites. Whereas most mite treatments are based on synthetic chemicals, predatory mites are used as a biological method of preventing and curing mite infestations.
Curculio nucum, the nut weevil, is a medium-sized beetle, with an especially elongated snout, characteristic of the Curculionini tribe of the weevil family (Curculionidae). Its larvae develop in hazel nuts Corylus avellana, being a serious pest in hazelnut orchards. It occurs in most of Europe, from south Sweden, Finland and Great Britain to the Mediterranean.
Sciaroidea is a superfamily in the infraorder Bibionomorpha. There are about 16 families and more than 15,000 described species in Sciaroidea. Most of its constituent families are various gnats.
The nematodes, roundworms or eelworms constitute the phylum Nematoda. They are a diverse animal phylum inhabiting a broad range of environments. Most species are free-living, feeding on microorganisms, but there are many that are parasitic. The parasitic worms (helminths) are the cause of soil-transmitted helminthiases.
Diflubenzuron is an insecticide of the benzoylurea class. It is used in forest management and on field crops to selectively control insect pests, particularly forest tent caterpillar moths, boll weevils, gypsy moths, and other types of moths. It is a widely used larvicide in India for control of mosquito larvae by public health authorities. Diflubenzuron is approved by the WHO Pesticide Evaluation Scheme.
A gnat is any of many species of tiny flying insects in the dipterid suborder Nematocera, especially those in the families Mycetophilidae, Anisopodidae and Sciaridae. Most often they fly in large numbers, called clouds. "Gnat" is a loose descriptive category rather than a phylogenetic or other technical term, so there is no scientific consensus on what constitutes a gnat. Some entomologists consider only non-biting flies to be gnats. Certain universities and institutes also distinguish eye gnats: the Smithsonian Institution describes them as "non-biting flies, no bigger than a few grains of salt, ... attracted to fluids secreted by your eyes".
