Garlic Fly

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Changed on: 08.11.2018

Garlic Fly

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Erwachsene Knoblauchfliege

The garlic fly is one of the most important pests in garlic cultivation in the East of Austria. This pest only infests winter garlic, not summer garlic, which is seeded in spring. Moreover, some types of garlic are more susceptible than others: the traditional, local type of garlic grown in the Weinviertel region appears to be less infested or, at least, more resistant to infestation.

Biology

The flies have red-brown bodies, a wingspan of about 18 mm with mostly translucent wings and a grey shine along the wing veins. Like all flies, they possess halters, dumb-bell shaped organs, instead of hindwings. The flies winter as adults.
Bild: Adult garlic flies are 14 mm long and brown-red in colour. Their wings show a dark shadow along their horizontal veins.

More information
caption
Erwachsene Knoblauchfliege

The garlic fly is one of the most important pests in garlic cultivation in the East of Austria. This pest only infests winter garlic, not summer garlic, which is seeded in spring. Moreover, some types of garlic are more susceptible than others: the traditional, local type of garlic grown in the Weinviertel region appears to be less infested or, at least, more resistant to infestation.

Biology

The flies have red-brown bodies, a wingspan of about 18 mm with mostly translucent wings and a grey shine along the wing veins. Like all flies, they possess halters, dumb-bell shaped organs, instead of hindwings. The flies winter as adults.
Bild: Adult garlic flies are 14 mm long and brown-red in colour. Their wings show a dark shadow along their horizontal veins.

More information

Symptoms

Symptoms

The garlic fly (Suilla lurida) only appears on winter garlic. The fly’s larvae can be found on garlic shoots from April to May. Visible damage on the outside plant can be found by the end of April/beginning of May.

The innermost, fresh leaves show signs of feeding to various degrees caused by the maggots: these symptoms can range from notches around the edges of the leaves and stunted, twisted leaves to the total growth failure of the main shoot.

Often, several weaker secondary shoots will be produced in such instances. The plant will look “ugly” and the cloves remain small.

 

 

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Typical symptoms of garlic caused by the garlic fly
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The white, rod-shaped eggs are about 1.2 mm long and appear strongly sculptured under the magnifying glass
Ei der Knoblauchfliege [Suillia lurida]
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The russet puparium is about 7 mm in length and can be found in the soil next to heavily infested plants
Puppen der Knoblauchfliege [Suillia lurida]
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Garlic infested by the garlic fly. Such damage will usually be visible once the larvae have left the plant and cannot be controlled anymore.
Durch Knoblauchfliege [Suillia lurida] befallener Knoblauch

Control

Control

One important measure that uses no chemicals is covering the garlic with fleece. This must be done immediately on the first nice spring days. The crop should be left under cover up to the beginning of May.

Another important issue is the choosing the right variety, as stem-forming varieties are less affected. Additionally, damage is not as severe in these varieties.

Chemical measures might include treatment with insecticides used to control the onion fly or other seed flies. The ideal time to start treatment is around early April. However, these chemicals are useless in low temperatures. In any case, wetting agents or surfactants should be added to the insecticide mixture.

The Institute for Sustainable Plant Production offers a Phytosanitary warning Services.

 

 


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