In the Open

Nelson Evening Mail, Volume 80, 29 November 1945, Page 8

In the Open

RHUBARB PIE “OFF” (By I. W. T. Munro) No rhubarb in the garden, and the family making quite a song about it. The first unfolding lea\4p began to raise the litter of straw with which the ruhbarb bed was covered but got no further. When the straw was cleared away, there were underneath a few withered stalks that had been cut off at ground level, and amongst them holes about the diameter of a lead pencil leading vertically downward into the ground, which disclosed the identity of the pest that had destroyed them. A Porina moth had cl.oscn to lay her eggs in the rhubarb bed. The Porinas are one of the few real pests native to New Zealand. There are a score of species, some extremely rare, some very common. The adult insects are large, handsome moths, with a wing span of up to two and a half inches, that often come in by open windows at night, being attracted to light. One of the best known is Porina umbraculata which occurs in several colour varieties, all marked, however, by a black-rimmed white streak, sometimes broken into several elongated dots, parallel to the leading edge of the forewing. BURROW DEEP The caterpillars—up to three inches long in the case of the larger speciesburrow deep into the ground, where they feed on roots during the day, but come to the surface at night, and sometimes clear the grass from large areas. Sometimes one swallows the spore of a fungus (Cordiceps robertsii), which grows until the whole caterpillar is turned into a hard pith-like substance —the well-known vegetable caterpillar which the Maoris used to burn to make tattooing pigment. All but one of caterpillars in the rhubarb patch had burrowed so deeply under the roots of the plants that they could not be got at, but a hedgehog has been visiting the garden recently, and is sure to catch them out sooner or later. The one that was turned up from a depth of -ten inches was just on three inches long, a robust creature, as indeed it should be when raised on a particularly tender and fine-flavoured variety of rhubarb. As it is not the larva of the common Porina umbraculata, it is continuing its life in a breeding cage until it reveals its identity as an adult, but even if it adds one of the rarest species to my collection, even, indeed, if, by a most unlikely chance, it turns out to be a hitherto unknown species that can be introduced to envious lepidopterists as Porina munroi, it will yet never be forgiven for the absence of rhubarb pie from the menu.