ENTOMOLOGICAL.

Otago Witness, Issue 1933, 12 March 1891, Page 5

ENTOMOLOGICAL.

Bx Entomologist. A NEW ENEMtTtO THE CODLIIf MOTH. An interesting discovery has lately been made with regard to the codlin moth whioh may or may not prove to be of value to the growers of apples. A number of raghidia j were sent some time ago to Mr R. Allan Wight, of AuoMland, Consulting entomologist to the Bay of Islands Agricultural and Horticultural Society, by Mr Koebele, of the United States Division of Entomology, to try their efficacy in New Zealand against the codlin moth. MrWight has perfectly satisfied himself of their value, but in trying experiments with these inseots he came aoroßS another, which will ver"y likely prove of even mote value than the im* ported ones, and has the advantage! of either being indigenous or already established by importation. Amongst a number of food experiments tried with a raphidia in the larval stage was one of offering ii a number of the American blighted aphides (Schisioneura lanigera), A number of whioh were eaten by the larva.After those left bad batiomd dry and shrivelled up, two oodlin moth larvae were introduced in the box, both in their cocoons, to see whether" the raphidia would attack them in that stage of their existence. As he failed to do so, one was dislodged, and next morning waß found to be dead, buj not eaten. As the raphidia had previously destroyed several oodlin moth larvae n was taken for granted (hat he had killed this one, and had nob e&tdn Ifcj Because he showed every symptom of being fully fed, and rtbotit to enter the pup* state. He was then removed to a new box, and the one he had lately occupied was set aside. The contents of this box were .- (1) The dead oodlin moth larvae ; (2) the oast off skin of the raphidia larvs ; (3) the oodlin moth larvte in its 00000 (4) the dead and dried tip aphides. On opening it several months later, it Was fou'ttd to contain (in addi-. tion) a Bmall two-winged ,ny afld its Cast off puparium. Mr Wight's reading of tile dsae was that; the cocoon of one of the oodlin moth larva mußt have contained the egg or larva of the fly, whioh after destroying the codlin moth la.rva had been transformed into the'perfeot insect. There was no possibility of the fly having entered the box in any other way, as it never had been dpetiod during tbo three months previous to the discovery. The box and its contents were Bent to Professor Sir 0. V. Riley for his opinion upon the case, and from the answer received the following is extracted i— "l have found (1) the raphidia larva dead, and BOiHewhat mildewed ; (2) the fly whioh you auapeot may be a pafaftits of the codlin moth ; (3) the oodlin moth coooon ; (4) a number of dried up speoimens of Schizoneura lanigera; (5) the oast skin of the raphidia; (6) the empty puparium of the fly. I carefully opened the cocoon of the codlin moth, and found the larva inside perfeotly whole and unpafatised. An examination of the fly shows it to be a.Bp-aoiea of Anthorurgia. The Jarva of these flies, as you 1 are* awtir^ Are mainly root feeders, but occasionally pfey ti^on other subterranean insects, and, if you are perfectly sure that the fly oould not have entered your box accidentally, my explanation wotfld be that you placed the egg, or a very young larval in th,e box with the Sohizoneuras, without notioingit, and that it fed upon these, and transformed successfully. Whether it normally feeds upon these insects when* flot in confinement is another question." It will be perceived that Professor Riley mistook the dead oodlin moth larva (out of its, ooooon) for that of the raphidia, a mistake very easily aodoUilted for owing to its decayed oondition, the faot of the raphidia Cast-off skin lying beside it and no special attention beiflg called to it, as it was presumed' by Mt Wight to have been killed by the raphidia, and it was taken for granted that the larva in the cocoon would prove to be the one killed by the fly larva. Another point is that the aphides were too long dead and dried up to have' nourished the fly larva, and aa in the United States they do not so often adopt the blightproof apple roots, ProfesEor Riley would be more apt to jlooU upon the aphides a3 " subterranean " insects than if he had known that they were taken from a twig. The fly certainly never entered the box unless in egg form in either of the dried up aphides, or the dead oodlin moth larva, whioh of them remains to be proved, but the chances are greatly in favour [of the latter, and if so, we may expect material relief from that source. Moreover, the orchard from which the Oodlin moth larvse were taken is 'probably the oldest and most severely infected in New Zealand, but of late years somejwell-known'oauaes have gradually been diminishing the pest. Last year the decrease was very palpable, and thiß year it is much more so. The early apples, whioh formerly lost every fruit from the moth, have saved at l9ast 30 per cent, this year, and no cure has been attempted. Another younger infected orohard within a short distance has had the moth entirely exterminated from an unknown cause. Again, this year an examinatfon of the soales of the bark shows a large number of dead larvee, whioh appear as if they had been partly devoured by some other inseot, Professor Riley'a obliging offer to transmit the fly to Mr T. A. A. Skuse, of Australia (the well-known iipterist), has been gladly acaopted, and from him and from observations by Mr Wight, we may hope to hear more of the matter. Should the fly prove to be indigenous, and the cause of the decrease of the oodlin moth, the apple growers of New Zealand will very probably have found their way out of the codlia moth difficulty.