[et_pb_section fb_built=”1″ admin_label=”section” _builder_version=”4.16″ global_colors_info=”{}”][et_pb_row column_structure=”1_2,1_2″ admin_label=”row” _builder_version=”4.16″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” width=”100%” global_colors_info=”{}”][et_pb_column type=”1_2″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_text admin_label=”squiggle-left” _builder_version=”4.27.2″ _module_preset=”default” header_font=”||||||||” header_text_align=”left” header_font_size=”22px” width=”100%” module_alignment=”center” custom_margin=”3%||||false|false” custom_padding=”||||false|false” global_module=”23371″ saved_tabs=”all” global_colors_info=”{}”]<\/p>\n
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Order: Diptera<\/span> Fungus gnats <\/span>include species in the genera <\/span><\/span>Orfelia<\/span> <\/span><\/span>and <\/span><\/span>Bradysia<\/span><\/span>.<\/span><\/span> Adults <\/span>are small,\u202fdainty\u202fflies that resemble mosquitoes and <\/span>are typically associated with plants grown indoors<\/span><\/span>. <\/span>They <\/span>are 3 mm (1\/10 inch) long, delicate, black flies with long legs and antennae, <\/span>and<\/span> a distinct \u201cY-shaped\u201d pattern on the forewings. <\/span><\/span>Unlike the common house fly<\/span>,<\/span> <\/span><\/span>Musca domestica <\/span><\/span>(Diptera: <\/span>Muscidae<\/span>), fungus gnats are weak fliers that<\/span> <\/span>move short distances in a<\/span> darting fashion.<\/span><\/span> <\/span>The <\/span>translucent<\/span> <\/span>larvae are maggots<\/span> that <\/span><\/span>measure up to 5.5 mm<\/span> (~1\/5 inch)<\/span> long.<\/span><\/span> They have<\/span> a black head capsule <\/span>and <\/span>reside<\/span> <\/span>in the soil of houseplants and plants grown in the greenhouse.<\/span> <\/span><\/span>Food may be visible in the gut upon close inspection.<\/span><\/span> <\/span><\/span>The pupae are small and oblong<\/span>.<\/span> The eggs of fungus gnats are <\/span>very small<\/span>, <\/span>oval, smooth, and white or semi-transparent.<\/span><\/span>\u00a0<\/span><\/p>\n [\/et_pb_text][et_pb_blurb image=”https:\/\/agsci.colostate.edu\/divi-agbio\/wp-content\/uploads\/sites\/127\/2022\/03\/fungus-gnat-larval-feeding-damage.jpeg” alt=”Fungus gnat larval feeding damage” _builder_version=”4.21.0″ _module_preset=”default” body_line_height=”1.4em” image_icon_custom_margin=”||-22px||false|false” global_colors_info=”{}”]<\/p>\n Fungus gnat larval feeding damage on poinsettia. Image credit: Penn State Department of Plant Pathology; Environmental Microbiology Archives, Penn State University, Bugwood.org<\/em><\/p>\n [\/et_pb_blurb][\/et_pb_column][et_pb_column type=”1_2″ _builder_version=”4.16″ custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||”][et_pb_blurb image=”https:\/\/agsci.colostate.edu\/divi-agbio\/wp-content\/uploads\/sites\/127\/2022\/03\/adult-gungus-gnat-1.jpeg” alt=”Adult fungus gnat.” _builder_version=”4.21.0″ _module_preset=”default” body_line_height=”1.4em” image_icon_custom_margin=”||-22px||false|false” global_colors_info=”{}”]<\/p>\n Adult fungus gnat. Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org<\/em><\/p>\n [\/et_pb_blurb][et_pb_blurb image=”https:\/\/agsci.colostate.edu\/divi-agbio\/wp-content\/uploads\/sites\/127\/2022\/03\/fungus-gnat-larvae.jpeg” alt=”Fungus gnat larvae.” _builder_version=”4.21.0″ _module_preset=”default” body_line_height=”1.4em” image_icon_custom_margin=”||-22px||false|false” global_colors_info=”{}”]<\/p>\n Fungus gnat larvae. Image credit:<\/em> Whitney Cranshaw, Colorado State University, Bugwood.org.<\/em><\/p>\n [\/et_pb_blurb][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.27.4″ _module_preset=”default”][et_pb_column _builder_version=”4.27.4″ _module_preset=”default” type=”4_4″][et_pb_blurb title=”Quick Facts” use_icon=”on” font_icon=”||fa||900″ icon_color=”#F15625″ image_icon_width=”36px” _builder_version=”4.27.4″ _module_preset=”default” header_level=”h3″ header_font=”|||on|||||” header_text_align=”center” header_font_size=”26px” background_color=”#FEBD3B” custom_margin=”|4%||4%|false|true” custom_padding=”4%|4%|4%|4%|true|true” hover_enabled=”0″ global_colors_info=”{}” content_max_width=”900px” sticky_enabled=”0″]<\/p>\n [\/et_pb_blurb][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.16″ _module_preset=”default” background_color=”#F1F1F1″ global_colors_info=”{}”][et_pb_row _builder_version=”4.18.0″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n\t\t <\/p>\n During their <\/span>seven-to-ten-day<\/span> lifespan, a<\/span> single female can<\/span> lay up to <\/span>200<\/span> eggs in soil media.<\/span><\/span> <\/span>Fungus gnat larvae usually <\/span>reside<\/span> in<\/span> the top <\/span>5-<\/span>8 cm<\/span> of the growing medium, depending on moisture level<\/span>, where they<\/span> <\/span>primarily <\/span>feed on fungi, <\/span>algae,<\/span> and decaying plant matter. <\/span>T<\/span>he larvae <\/span>can <\/span>feed on plant roots and leaves resting on the growing medium surface<\/span>. <\/span><\/span>After about <\/span>20 days<\/span>, the larvae pupate near the surface of the <\/span>growing medium. <\/span>Adult <\/span>fungus gnats <\/span>are usually seen<\/span> in <\/span>growing media, plant foliage, compost, wet piles of mulch<\/span>, or other areas in the vicinity of an <\/span>infested plant<\/span>.<\/span><\/span> However, adult flies <\/span>are attracted<\/span> to light and <\/span>may disperse short distances<\/span> where they accumulate<\/span> <\/span>around window frames. Moist-growing media <\/span>containing<\/span> <\/span>high amounts<\/span> of peat moss are particularly attractive to adult females.<\/span> <\/span><\/span>The entire life cycle can <\/span>be completed<\/span> in <\/span>17 days<\/span>, depending on temperature. <\/span>Fungus gnats produce multiple overlapping<\/span> generations each year.<\/span><\/span>\u00a0<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.18.0″ _module_preset=”default” background_color=”#FFFFFF” global_colors_info=”{}”][et_pb_row _builder_version=”4.18.0″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” background_color=”#FFFFFF” hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n Larvae<\/span> of fungus gnats feed below the soil surface on roots. When densities of larvae are high, feeding injury can lead to stunted growth and increased susceptibility to microbial infection, especially in seedlings and younger plants.<\/span><\/span>\u00a0<\/span><\/p>\n Adult fungus gnats do not bite, but they are a nuisance indoors when their numbers are high. Adult fungus gnats tend to be most noticeable during late fall and winter. Decreased day length and cooler temperatures slow plant growth and water usage. If watering practices <\/span>are not altered<\/span>, particularly during fall and winter, the growing medium will remain moist, which improves conditions for fungus gnat development. Furthermore, as the growing medium ages or degrades it tends to <\/span>retain<\/span> more moisture, which will attract fungus gnat adults.<\/span><\/span>\u00a0<\/span><\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.16″ _module_preset=”default” background_color=”#F1F1F1″ global_colors_info=”{}”][et_pb_row _builder_version=”4.18.0″ _module_preset=”default” global_colors_info=”{}”][et_pb_column type=”4_4″ _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}”][et_pb_text _builder_version=”4.27.4″ _module_preset=”default” background_color=”#F1F1F1″ hover_enabled=”0″ global_colors_info=”{}” sticky_enabled=”0″]<\/p>\n While yellow traps alone will not significantly reduce fly densities, they can <\/span>be used<\/span> to <\/span>monitor<\/span> fungus gnats when deployed in the greenhouse. Often, adults can also <\/span>be <\/span>observed<\/span> flying or resting on surfaces.<\/span><\/span> Yellow sticky cards can <\/span>be used<\/span> to trap adult fungus gnats and should be placed under the plant canopy or on the edge of containers.<\/span> <\/span><\/span>They can also <\/span>be deployed<\/span> near seeded plants to help <\/span>monitor<\/span> the number of adults.<\/span><\/span>\u00a0<\/span><\/p>\n <\/span>An effective means of detecting fungus gnat larvae<\/span> in larger pots<\/span> is to insert \u00bc inch slices of skinned potato into the growing medium. Larvae will migrate to the potato <\/span>within <\/span><\/span>24-<\/span>48 hours<\/span><\/span>, at <\/span>which point the potato can <\/span>be removed<\/span> <\/span><\/span>to <\/span>determine<\/span> whether an infestation is present.<\/span> The threshold at which significant feeding injury can <\/span>be expected<\/span> is three to five larvae per potato slice in propagation pots, or 15-20 larvae in production pots.<\/span><\/span>\u00a0<\/span><\/p>\n The most important strategy to minimize fungus gnat problems associated with plants grown indoors is to allow the growing medium to dry between watering, especially the top 1 to 2 inches. <\/span>Watering should only be done when necessary to maintain plant health and productivity, as allowing the soil surface to dry will kill eggs and larvae. Indoor collections of standing water should be eliminated and plumbing, or irrigation leaks should be addressed.<\/span><\/p>\n Examining the soil of new plants can help prevent the introduction of fungus gnats to clean areas. It is also recommended to re-pot plants, particularly when the growing medium is retaining too much moisture. Populations in the greenhouse can be suppressed by reduction of breeding areas. For example, removing decaying plant matter, soil and standing water from underneath benches. Any containers with an abundance of decaying plant matter should be removed such as decayed bulbs and roots, which are a food source for fungus gnat larvae. <\/span>It is recommended that pasteurized container or potting mixes be used in areas where fungus gnats are problematic, and commercial growers can treat growing media with heat or steam to kill developing flies, algae, and microorganisms. In home gardens, soil can be moistened, placed in a transparent or black plastic bag, and left on a sun-exposed elevated surface for 4-6 weeks. For this approach to work, the pile depth should be limited to 20.5 cm (8 inches).<\/span> In greenhouse systems, fungus gnat entry can be prevented by storing potting soil indoors or sanitizing via steam or autoclave before potting plants sensitive to fungus gnats. <\/span>Infested plants should not be introduced to clean areas and should be discarded if possible.<\/span>\u00a0<\/span><\/p>\n
Family: Keroplatidae, Sciaridae<\/span><\/p>\nDescription<\/h2>\n
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Life history and habits<\/h2>\n
Injury<\/h2>\n
Monitoring<\/h2>\n
Cultural control<\/h2>\n
Biological control<\/h2>\n