Transcript 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 TIFF (Uncompressed) decompressor are needed to see this picture. 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):