Download Leaf Miners

Leaf Miners
The Holly Leaf Miner
Leaf Miners
• Leaf miners are the larval stage of several insects,
often small moths or flies, which obtain their food by
living and feeding within leaves.
• Particular species prefer particular plants.
• Feed in characteristic patterns, resulting in the
formation of visible “mines”.
• These may take the form of a winding channel
through the leaf or a large, discoloured patch, known
as a blotch mine.
• Source: © South West Lakes Trust 2006
• http://www.swlakestrust.org.uk/fileadmin/packs/leafminer.pdf
The Holly Leaf Miner
• The holly leaf miner is a fly (Phytomyza ilicis ), a very
common invader of holly leaves. Evidence of its
occurrence can be found on most holly trees. Its mine
consists of a brownish-yellow patch on the upper
surface of the leaf, varying in size from 1 or 2 mm
across to almost the whole leaf area. The life cycle of
the insect is as follows:
» Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
•
Life-Stage
L
L
– A =adult fly
L/P
P
E=egg
P/A A/E/L L
L
L=larva (grub)
– © South West Lakes Trust 2006
L
L
L
P=pupa
L
The Holly Leaf Miner
• Picture from Surrey Tree Wardens Pests.pdf
QuickTime™ and a
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Holly Leaf Miner - predators
• The leaf miners are not wholly protected inside the
leaf and are preyed upon by birds, particularly blue
tits.
• Look carefully to reveal evidence of blue tit predation,
- their beaks leave large tears in the mine.
• Tiny parasitic wasps are often associated with leaf
miners. They lay their eggs within the body of the
larval leaf miner and when the wasp eggs hatch, the
larvae of the parasite feed on the living leaf miner
larvae.
•
© South West Lakes Trust 2006
Symptoms & Significance
• Irregular creamy-green to yellowish blotch on leaf
with brown to purple-brown centre.
• Area raised, usually on top side
• Cavity in leaf thickness if epidermis cut
•
Widespread & common
•
Disfiguring, more common on leaves lower to ground
•
Source: Surrey Tree Wardens
•
http://www.surreytreewardens.org.uk/index.php/trees-pest-and-disease
Holly Leaf Miner - Control
• Mar/Apr - pick and burn leaves
• No chemical control recommended
•
Source: Surrey Tree Wardens
•
Source of images: University of Georgia
http://www.forestpests.org/leafminers/miners/phytomyzailicis.html
Leaf Miner Links
• http://www.rhs.org.uk/advice/profiles1200/holly_leafminer.asp
•
•
See following links for more on the leaf miner, Holly and other trees.
http://www.gla.ac.uk/services/estates/Sustainability/Biodiversity/trees/holly.html
•
http://www.treesforlife.org.uk/forest/species/holly.html
• Other leaf miners include
Rhynchaenus fagi
(Beech Leaf Mining Weevil):