LEAFLETS FOR GARDENERS AND FRUITGROWERS.

Otago Witness, Issue 2356, 20 April 1899, Page 8

LEAFLETS FOR GARDENERS AND FRUITGROWERS.

No. 32.— THE QUEENSLAND FRUIT FLY (Tephrites). By T. W. Kirk, F.L.S., etc., Lond., Government Biologist.

Mr Froggart and Di Cobb, of New South Wales, and Mr Tyron, of Queensland, have paid so much attention to this subject, and favoured me with so large an amount of information, than I cannot do better than reproduce portions of their notes: —

" General Appearance of Fruit Attacked. — iWhen the eggs are deposited in the fruit before it is ripe, which is often the case, it (shows very slight outward evidence of disease, but when ripening it shows darker spots .where the skin has been pierced by the ovipositor of tho flies. As the newly-hatched maggots begin tc feed they gnaw irregular passages towards the centre of the fruit, and in the case of apples, quinces, and other corefruit soon reduce that portion surrounding the core into a rotten mass, which, when jujened ouU jg fteen Jo contain a number of

pale-coloured maggots. In the case of peaches, apricots, and stone-fruit, though the maggots feed inwards, the whole of the side first attacked soon begins to decay. "The maggots are semi-transparent when about a quarter grown, with the head portion slender, the body thickening towards the extremity, and sharply rounded at the tip. With an ordinary lens they can be easily identified from codlin-moth or any other grub fruit by the general elongated form, the two curious black hooks at the mouth, and a pair of cephalic spiracles, tinged with yellow, at the opening at the back of the head, which stand out very distinctly. Their mode of progress is by crawling, but, though without legs, when placed upon a smooth surface, by arching up their backs and drawing the tip of the body down to the head, they can, with a sudden jerk, jump a considerable distance in a similar manner to the jumpers in cheese. "They live in the fruit until it is perfectly putrid, and when full grown are of a dull yellow colour, measuring about half an inch in length. At this stage they crawl out of the fruit and bury themselves in the earth just beneath the surface, and transform into elongate, , oval, brown pupae, enclosed in a brown hard shell, like those of the house fly so "common in stables. "The flies vary somewhat in size in sexes,tho female fly, as is often the case in insects, being considerably larger than the male, with the body more robust, and the tip tapering into a needle-like ovipositor, with which she does all the damage. She measures nearly half an inch across the expanded wings, which are semi-transparent except along the front nervure, with an oblique clouded--line near tho shoulder. The head is broad, with large red-dish-brown eyes ; the antennae yellow, with the third joint long, lipped with a bristle ; the thorax is stout, of a dull yellowish-brown colour, with a few long hairs on the side, and a bright yellow patch on each side and another over the scutellum at the junction with the body ; the latter constricted at the base, swelling out in the centre, and tapering again to the tip ; it is of a general dark reddish-brown colour, showing a very distinct transverse yellow band across the upper half of the abdomen. " Remedies. — The only way to check the spread of this pest is for all fruit-growers to be on the watch and examine and destroy^ all fruit found to contain these maggots, while all fallen fruit should be gathered up and destroyed. A 6 the maggots do nol leave the fruit the moment it drops, as the codlin-moth caterpillar does, there is a much better chance of killing most of them at this stage. Lime, or some caustic top-dressing, could be spread, under infected trees, the surface of the soil having been first raked ovor, and if this was done a few days before the dressing the magpies and other wild birds, as well as the farmyard fowls, would make short work of a great number." Note by Dr Cobb on the Fruit-fly, or socalled " Queensland Fruit-fly " : — " The fruit-fiy attacks principally peaches,

shine, where birds also can pick it up) that its death ensues before it can come forth to propagate. "3. The ground under the trees can be poisoned with kerosene and a variety of other substances that are fatal to the grubs and pupae. "4. Poultry are said to pick up the flies and grubs to a certain extent, but the evidence on this head seems to me not very satisfactory. "5. Trees have been covered with a very fine-meshed netting for a month before the fruit is ripe, and the flies have thus been kept off the fruit. "6. Undoubtedly, the most effective way to fight this pest would be by concerted action under the administration of the Government. There is now nothing to prevent infeEted fruit from being sent from one part of the colony to another, and thus spreading the pest at a rapid rate. If the Minister for Agriculture had power to inspect and condemn and destroy in the Sydney market alone any such diseased fruit it would put a strong check on the spread of- the pest. ' ' 7. Anyone who takes any of the above precautions should ' induce as many as possible of his fruit-growing neighbours to adopt them also. "8. In their own interests fruit merchants might reasonably .refuse to buy fruit from orchards or districts whejre the ny is known to be prevalent. Fruit in store and in market should ha picked over and the infested 'part removed and destroyed. "9. Various attempts have been made by hanging in th« fruit trees substances having an obnoxious- odour to drive away the flics — not, however, with much success. "10. A remedy -I have myself conceived (of course, if may "also have been thought of by others) is 'to tra}? the" flies with fruit. I£ when the fruit is 'picked for market a tree with tempting fruit be Teft near the middle of the orchard, all" the flies will resort to it as the only place to deposit eggs. In due time the destruction of all tho fruit of thiß tree, and a careful treatment of the ground underneath, would put a great check on the number of flies. I believe this idea may be capable of development into the mo6t economical and effective means of fighting the pest. It would not be necessary that the fruit should be displayed on the tree alone ; it might also, after plucking, be so placed as to form an effective ' bait,' the idea being to attract a large number of flies into comparatively a small quantity of fruit, where they could be easily destroyed. Comparatively useless fruit might be utilised for this purpose." * There are other dangerous insects the importation of which from Australia should be guarded against, and the statement that we have already one, at leaßt, of them in this country should not be allowed to stand in the way of applying all possible means to prevent further supplies from entering our colony. I refer more particularly to the red scale and the San Jose or pernicious scale. Although I should be sorry to see anything

(Fig. 1) Infested apricot. (A) Maggot. (B) Holes where maggot has escaped. After Claude Fuller. Fruit infested by the Queensland fly (Tephrites tryoni) not being obtainable at the time of my visit, the drawing of an apricot attacked by the West Australian fruit fly (Halterophora capitata) is reproduced hero to give an idea of the appearance of infested fruit, the mode of attack being described as similar. (Fig. 2) Mnggot magnified (Tephrites tryoni). (Fig. 3) Pupa magnified. After Froggalt. (Figs. 4 and 5) Back and side view of fly, magnified —original. The line below Fig 5 shows the natural length.

apricots, plums, nectarines, apples, and pearß, though other sorts are not exempt. "The injured fruit may be known by the following appearances: Although it retains ita form, there appears under the skin, at one or mcro places, a discolouration as if the flesh had turned watery, and had become somewhat decayed. On opening the fruit it is found to be honeycombed and rotten at the centre, and the dirty-brown, often semiliquid flesh contains one or more fly-blows or maggots, which are never quite po large as those of the common blow-fly, but otherwife tc the ordinary observer much the same, These appearances are seen only in ripening fruit. The fly docs not attack green fruit, A email pore in the skin of the fruit is often seen near the centre of the waterylooking discolouration. "The fly-i.e., the adult winged insect-is seldom seen, even in orchards where it is very prevalent, in which respect this pest resembles the codlin moth, though not for the same reason "The female fly lays her egg under the skin of the fruit, and this is the reason that the insect is so hard to combat. The egg of the codlin moth being laid in the eye of the apple, the grub, when it hatches, has to eat its way into the apple; consequently, if the apple be sprayed with Paris green the young codlin moth grub getting a bite of it is poisoned, and thus got rid of. The grub of the fruit-fly, however, hatching as it does inside the frit, cannot be poisoned in the same manner as that of the codlin moth. "The grub of the fruit-fly requires about three weeks to develop, so that a number of broods follow each other" each season. This fact will account for the great number of the grubs to be found iv some Queensland orc|iar^!. "The jomraon small brown fly that attacks decaying fruit in swarms should not be confounded with the pestiferous fruit-fly. This common little brown swarming fly thrive* only on decaying or fermenting fruit. " Remedies.—These must be directed towards destroying and warding off the fly in all its stages. Spraying is useless. Constant vigilance is absolutely necessary if the pest is to be got rid of where it has once becomo well established. "1. Destroy all infested fruit .19 fast as it is found. Boil it for the pigs or poultry or other stock. "2. Cultivate the ground under the tree 3 frequently. The grub leaves (he fruit and goes into the ground to propagate before changing into a fly. It goes in only a little way, and cultivation is likely to so disturb ' it (i.e., bury it or bring it up into the sun- I

done which would check the free interchange of colonial fruit, believing as I do that only by this means will the fruit industries of Australasia reach their fullest development, yet I must most strongly urge ihat at least the three insects above named be placed on the same footing as the codlin moth, and the importation of fruit infected with either of them totally prohibited. In Now South Wales there is at present no legislation for the suppression of insect and fungus pests, except those affecting the vine, but efforts are now being made to remedy this defect.* Many orchaidihts, however, udopt careful and systematic spraying as a means of keeping disease in check, and in most instances with satisfactory results, One firm alone .sold 120 Knapsack pumps last season, besides a considerable number of Nixon Climax for larger areas. The same complaint v, however heard there as from energetic growers in this country-viz that careless neighbours nullify the effects of then' exertions. In S °ulh, Australia strong efforts are being ".acle to check all insect and fungus pests «»d strict reflations are being enforced f Z*^ thos6 wl £ ne«^ct to properly attend \° "»eir trees. Here Mr Quin, the Orchard Inspector, has found that the best treatment t™ scale insects on 2itrus trees is cyanide *«., (For description see my report for ■">:*>•»£> . In Wona most stringent examination is ™ade °f al Plant s' e-lc" f W»*<£. aud they. a ™ . «jiPPed °r fumigated by Government offi«al 5 before being handed over to the imP°iteis. . . Iv Tasmania, where the conditions and £ lulfc productions most nearly resemble those fou, nc "\ our. col °ny> orchardisls are compelled to bandage their trees and examine the bandages at stated intervals in order to kill tho S rubs °f codlln moth- .On orchards of a. n >' extent women are employed to do this duty and it is work that they may well underlake. Under another head I shall briefly describe how I saw this work performed m on ° visited, UctODer iear. , T No. 45.—CORN-SPURRY YARR (Spergula arvensis). By T. W. Kirk, F.R.M.S., F.L.S., etc., Lond., Government Biologist, Tho corn-spurry or yarr was introduced from Europe. It is a small, succulent herb, lft or more in height. Much branched from the base. Leaves arranged in whorls, and needle-shaped, a branch looking somewhat like a bit of pine, but of course much 3ofter. The flowera are small and white. In some partb oX ISurone aud aleo ia North

America spurry is grown as a special crop, and is considered very valuable, both for dairying &nd for sheep. It is also used a% green manure. In England and here, however, it has proved itself a most dangerous

If there is time the second crop, which i*> pretty sure to come away rapidly, may bo treated in the same way. A quick growing root crop may be taken off; and thorough cultivation will complete the work, or tho-

and injurious weed, being found from Auck- • ground may be sown to grass. Various modiland to the Bluff. In some parts of South- fications of this treatment have been 8ucco"8land especially it infests cornfields to such ful> Shoukl even few lants be kft v an extent as to materially reduce the yield. .„ •<•.., \ 1 1 „ Spurry in fallow ground has been mastered wIU 9OOn remfect the whole ground, thoby thoroughly harrowing the ground while quantity of seeds produced is so .arge. the spurry is young. A very little harrow- Seed is found mixed with farm seed. It ing in dry weather will tear up all the young has also been detected in considerableplants, and exposure to the sun will kill them, quantity in some samples of guano.