Art. XL.—On the Occurrence of the Black Vine Weevil (Otiorhynchus sulcatus) in Nelson.

Transactions and Proceedings of the Royal Society of New Zealand, Volume 22, 1889, Page 338

Art. XL.—On the Occurrence of the Black Vine Weevil (Otiorhynchus sulcatus) in Nelson. By R. I. Kingley. [Read before the Nelson Philosophical Society, 5th November, 1889.] I am not aware whether or no the Otiorhynchus sulcatus is common in New Zealand. I should not at all be surprised to find that it is far more common than is generally supposed, from the simple fact that the insect in its perfect form commits its ravages when the owners of the food-plants are, or ought to be, retiring for the night—i.e., after 9 or 10 o'clock at night. In the daytime they are invisible unless the cracks and crannies of walls or the clods of earth are examined, when they will be found reposing with a very harmless and innocent aspect. From the destructive nature of this species of insect—destructive in both its larva and imago states—it is most desirable to make the public aware of its presence in the colony, since it is said to be not indigenous, but one of the imported European pests. On the 20th of last October Mr. Burford, who has recently commenced cultivating grapes, and has at considerable expense erected two glass houses, each some 80ft. long, called

to inform me that he had discovered upon his vines, at night, an insect new to him, which evidently was feeding upon the young shoots and leaves, and was present in immense numbers. From the specimen shown by Mr. Burford I at once recognised it as a weevil (Otiorhynchus), but was not certain as to its species. I therefore sent it on to Mr. Maskell, of Wellington, who very kindly obtained from Mr. Kirk its name, and also references to one or two books describing its habits, &c. From Miss Ormerod's book, “Injurious Insects,” page 305, I gather the following particulars of its habits and date of appearance (the latter I have changed to correspond with the difference of the seasons in New Zealand): “The eggs are deposited a little below the surface of the ground in the spring or early part of the summer. The maggot, or grub, is legless, whitish, somewhat hairy, and is to be found from about February to the following spring at the roots of its food-plants. The pupa is yellowish-white, and may be found about September, lying 3in. or 4in. below the surface, where it remains only about fourteen days before development. The weevil itself is of a dull-black colour, about ⅜in. long, with a short snout or proboscis; the body between the head and abdomen is granulated; and the elytra, or wing-cases, are rough with raised lines, and somewhat prettily marked with orange spots, which by means of a powerful magnifying-glass are seen to be composed of small tufts of golden down.” Some idea may be formed of the immense numbers infesting Mr. Burford's vines when I state that, although for the last fortnight he and his men have destroyed hundreds almost every night, yet when I visited the houses at 11 o'clock one night last week they were still to be found on nearly every young shoot. It is impossible for these large numbers to be produced suddenly in one season, and I should say they have been in the garden for several seasons unnoticed, as they probably would have been this year had not Mr. Burford had special reasons for visiting his houses after dark, and thus detected the reason that his young shoots were looking so sickly and otherwise not thriving as they should have done. I exhibit specimens of the beetle obtained from Mr. Burford's vines, and for the benefit of those persons interested in vine-growing I subjoin some of the suggested remedies and preventives. As the weevils only make their appearance by night, a commonly-adopted method is to spread white cloths below the branches, and to shake the beetles down at night, gathering them up and destroying them in hot water. It must be borne in mind that these beetles drop off on any disturbance or when a strong light shines upon them.

All crevices in the walls of houses should be stopped up, and clods of earth removed, and it might be advisable to run a line of ashes next the wall, sprinkled with a little kerosene, or a weak solution of carbolic acid in the proportion of one part acid to one hundred parts of water. With regard to the larva, where attacks have been going on during the growing-season the roots should be thoroughly examined during the winter, and all maggots destroyed, and the roots dressed with lime, soot, or similar applications. The best remedy for a vine-border is to clear it away and replace with clean soil. Watering with a strong solution of ammoniacal liquor and common agricultural salt is effective in preventing the increase of this pest.