Fungus gnats 
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Fungus gnats
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Fungus Gnats
Adult fungus gnats are 2 - 5 mm [1/12 - 1/5 inch] long, grayish black with long antennae. The larvae are up to 8 mm [1/3 inch] long, transparent with a black head. The larvae are found in the top two cm [1 inch] of the soil. The pupae are 3 - 6 mm [1/8-1/4 inch] long and gray to light brown colored. Fungus gnat larvae feed on decaying plant material, algae, fungi and on fine roots and root hairs which causes direct damage to the plants. Indirect damage is caused by spreading diseases such a Pythium , Phytophthora and Fusarium. Young seedlings or cuttings are very sensitive to fungus gnat larvae. Conditions that favor fungal and algal growth enhance the fungus gnat problem, good irrigation management can reduce the fungus gnat population significantly. In crops where fungus gnats are expected, a preventative application of beneficials is recommended. Hypoaspis miles and nematodes can be used alone or combined. The correct strategy depends on the crop, irrigation system, the amount of fungus gnats. Beneficials: Hypoaspis miles Nematodes [Steinernema feltiae] Monitoring: Yellow sticky cards, potato slices - attract larvae and adults Physical/Mechanical controls: Soil replacement, diatomaceous earth. If the soil is allowed to dry out, this sometimes will kill off a number of fungus gnats as they do not thrive well in dry soil. Chemical Controls: Pyrethrins, foliar spray, nicotine spray [for adult fungus gnat]. |
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