Spotted Tentiform Leafminer: Appearance, Territory, Damage and Life Cycle

Latin Name: Phyllonorycter Blancardella

Appearance: The adult is a little beige moth with extensively fringed wings that are patterned with golden brown and white lines. Individual eggs are placed on the underside of the leaves. The yellowish larva lives inside the leaf and has a black head.

Hosts Plants: The spotted tentiform leafminer eats apple leaves. Mines are occasionally found in several crabapple cultivars, especially decorative blooming crabs.

Territory: The spotted tentiform leafminer (Phyllonorycter Blancardella) is a Gracillariidae moth. It is well-known throughout Europe, stretching east to Ukraine and central Anatolia.

Damage Insect Cause: STLM is a sporadic pest of apple trees; the larval stage feeds internally inside leaves, forming a unique leaf blotch known as a leaf mine. A leafminer is an insect that feeds internally within a leaf. When completely built, STLM’s hollowed-out mine is oval and rises along its long axis, resembling a tent, and its upper surface is speckled. Although there is no direct feeding on the fruit, if a tree is extensively infected, it may get stressed enough to affect the fruit. STLM is prevalent enough in household apple trees that the mines may be seen, although it seldom occurs in large enough numbers to cause tree harm or fruit loss.

Life History and Habits: They remain dormant during the day and fly mostly after dusk, but they may continue to fly late into the night if temperatures are high. Adults deposit very little, nearly transparent eggs on lower leaf surfaces after mating. When the egg hatches, the larva burrows immediately into the leaf and eats for the rest of its life. This larva is just 1-2 mm long at this stage. The leaf mine is only visible from the lower leaf surface at this stage. When the larva has finished eating, it develops into a pupa within the mine. The length of the life cycle varies with temperature, with the first generation taking significantly longer than the second. The second adult flight usually takes place in early July, with the third trip taking place in mid-August.