Some infestations spanned a number of years, in a few cases more than five. Maple leafcutter damage has been noted since the 1850s, with significant outbreaks in New York State in 1911, the early 1920s and in 1997 the mid-1970s in Vermont and New Hampshire and 1981 in both Vermont and Ontario.
Leafcutters finally leave their homes when they emerge as adults in spring. In September, when they are mature, leafcutter larvae descend to the ground, carrying their homes with them, and wriggle into the topsoil to pupate. This feeding causes more significant damage than does the leafminer stage. The case protects them as they feed on the leaf in a manner known as skeletonizing, consuming all green tissue between veins, and when they move to another part of the leaf they leave behind a round scar. Allen, Professor of Forest Entomology at SUNY ESF, they are “a moth with a mobile home.” They then combine two of these discs to use as a protective case. Once the wee caterpillars are big enough to “run with scissors,” they use their sharp mandibles to excise rounds of leaf tissue. Larvae, which are infinitesimally small (okay, slightly larger than that but not much) at that point, do minor damage in the miner phase, and in fact their burrows are difficult to spot. When they first hatch in mid-June, leafcutter larvae burrow into maple leaves and begin “mining” tissue between the upper and lower epidermis, or skin, in a circular pattern.
The maple leafcutter (Paraclemensia acerifoliella) moth, a tiny insect that is rarely noticed, is a native pest with a steel-blue body and a bright orange head (although I could probably say anything once I’ve told you it’s hard to see).
It sounds like another joke, but it’s true. What’s actually going on is that the maples are moth-eaten. In addition to holey-ness, leaves also exhibit circular brown patches, and by September some had turned entirely brown and fallen off. Beginning in August, near-perfect circles of leaf tissue have gone missing from sugar maples, and from other trees to a lesser extent, as if swarms of Hole-Punch Fairies had gone berserk. Only a joker would argue that plant breeders have secretly crossed our beloved sugar maples with Swiss cheese, but given the way this year’s maple leaves are riddled with mysterious holes, it almost seems a plausible explanation.
0 kommentar(er)
