THE HORNTAIL BORER

Hokitika Guardian, 7 May 1929, Page 2

THE HORNTAIL BORER

PARASITIC LI BERATED. For some years past the horntail !)orer lias been found in dead tree. of several species of con iter in the S ate ■plantations at IJanmer and Baiun ral, inciludiug 'Pimts .radiata., P larieio, P. ponderosa, P. anstriaca, P. miiricata, P. lmirrnyana and larch. It apparently coniines its attentions to .lead or dying trees of a more or less sickly nature which would succumb in any case. Damage has been infinitesimal so far, practically confined to a Iracimn of 1 per cent. Thu insect was noticed :n this country over twenty years ago and, since then, the damage recorded is of little account considering the wide field it lias had to operate over and the opportunity to multiply. Recently l>r Millar, of the Cawthron Institute, lias been rearing broods of the parasite, Rhyssa -persuasoria, for distribution throughout the infested areas, and, within the past two months, several consignments of -his nseet have been liberated in the State Forests at Hnnmer and are now “getting ibusy. M The female _ parasite, seeking out the egg deposits of the hafntnil, Sets its eggs in close proximity, and the grub when it hatches out, immediately attaches itself to the grub of the horntail, ou which it feeds and so eventually kills. , The parasite is very similar in appearance to the horntail, hut about one-third its size, and the female is larger than the male. It is hoped that this little insect will eventually curtail the depredations of the horntail. even if it does not entirely exterminate that insect.