Damage to leeks





Damage & Detection







 
Damage, Monitoring and Detection

The leek moth larva is a small, leaf-mining caterpillar. The first generation (May-June) feeds on the leaves. The worst damage is done by the second generation (July-August) as it continues to damage emerging leaves (Figure 1) and moves towards the bulb. Feeding damage stunts plant growth, introduces rot and can compromise the storage life of onions and garlic. In New York leek moth populations have been found in onions, garlic and leeks.
Damage    

Figure 1:
Damage to Leeks
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PHOTO: Lorraine Chilson

   

Where to look on various crops

On crops with hollow leaves (onions, shallots and chives), the larvae feed on the inside tissue, leaving characteristic ‘windowpane’ damage to the leaves (Figure 2 & 3). Split open damaged leaves and look for frass (excrement) and debris (Figure 4). Even after the larvae have left to pupate, the telltale debris remains visible (Figure 5).

Windowpane   Shallots

Figure 2:
Typical windowpane damage on Onion
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  Figure 3:
Typical damage on shallots
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Figure 4:
Onion leaf split open, larva and debris visible
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  Figure 5:
Telltale debris
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On garlic and leeks, larvae feed on the leaf surfaces and sometimes tunnel through the leaves(Figure 6). They are often found in the protection of the folded leaves on leeks and garlic (Figure 7). In June in hardneck garlic, damage will be the most noticeable on the garlic scapes (Figure 8). On both crops check the newest leaves as well.(Figure 9)

 

Figure 6:
Damage to leeks
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PHOTO: Lorraine Chilson

  Figure 7:
Damage to garlic inside fold of leaf
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Figure 8:
Damage to garlic leaf and scape
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  Figure 9:
Leek - Check newest leaves for damage
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PHOTO: Lorraine Chilson

Click here for look-alike damage





 
 


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