ORCHARD NOTES

Manawatu Standard, Volume LIX, Issue 116, 17 April 1939, Page 5

ORCHARD NOTES

CONTROL OF CODLING IMOTH (By L. R. Reriouf, Orchard Instructor, Department of Agriculture, Palmerston North). During a long dry, season similar to that which lias just been experienced codling moth will cause very extensive damage to iTuit ; unless very careful consideration is given to its. control. To fully understand control | methods, a knowledge of this pest’s life history is essential. Tho codling moth passes the winter in the full grown larval stage in a thick, silken-like cocoon. The larvae are pinkish white caterpillars with brown heads, and are about fiveeighths of an inch long. Those cocoons are generally developed under loose scales of tbe bark in the trunks of the trees, or in cankered or damaged limbs, and in and around packing sheds. Tbe larvae remain dormant throughout the winter, being able to stand low temperatures. During the pupating period the grubs eliange inside their cocoons to a brownish stage, and, after two to I four weeks, they emerge as greyish ninths with somewhat iridescent, brown patches in the back part of tho front wings. The moths have a wing expanse of from Jin. to -jin. During the day tho moths remain quiet,- but about dusk, especially if the temperaturf' is high, they become aoti\e, junto, and the females lay their eggs. Each female deposits about oO eggs and these are mid on the fruit and the leaves. The eggs hatch in from eight to fourteen days, depending on climatic, conditions, and after a few hours hegin to chew their way into the fruit, fin becoming full grown, tliev tunnel to the outside of the fruit, then leave in search of a suitable place to develop a cocoon; tliev then develop ns before, and the life cycle continues its revolutions. ' After taking into consideration the stages of development of the codling moth it can be seen that control measures do not consist of sprn.ving alone. Hut can bo placed under three hoad"lgS’ ORCHARD SANITATION.

'Phis imiMirtant feature of the control of codling moth is frequently the most neglected by growers. At the end of each season, the orchardist should take particular care to examine his packing or storage sheds and kill all codling grubs which have crawled from infested fruit and made cocoons in cracks and sheltered places. Cases used for carrying fruit- from the orchard and second-hand cases returned to the orchard should be examined and all grubs killed. This is one of the chief sources of introduction of codling moth into orchards. During the harvesting season, infested fruit rejected should not l>e left about tile shed, but immediately destroyed or fed to pies. BANDAGING OF TREES.

Bend aging the trees by placing around the trunks some material, which will act as a trap for the larvae, is ,a definite aid in the control. Banfl a ces may consist of two types: (a) Sacking bandages; (b) chemically treated bandages. . Sacking bands consist ol strips of clnselv woven sacking six fo eight, inches wide, folded over once, with the opening of fhe fold facing downward. The bands are fastened around the trunks of the trees about 9 inches from the ground, by using fine round headed nails, so that they are easily detachable This is done not later than the middle of November, and the bands are left on until mid-winter. _ when using sacking bands it is essential that tliev be examined every fen days and all grubs killed. If this is not done it is much better to have no bandage at all. as Hie sacking would form ideal breedino- grounds for codling. Before plaoingGlie bands on the trees all rough bark should be scraped oft the The s object of the chemically treated bandage ‘is similar to that ot the sacking, with the addition that it is designed to destroy all grubs that enter, thus obviating the necessity for regular examinations. These bands, consisting of strips of corrugated strawlioard two to three inches wide, treated with a chemical mixture, are attached to the trunk of the tree with tho corrugated side next- to fhe hark, and le p t until mid-winter, when they are collected and burned. STRAYING. The two processes mentioned above are only the foundation of the control of codling moth, and it. is necessary to rarrv out a thorough spray programme to completely combat this pest. In most districts codim moth is usually active by petal fall, and it is then necessary to apply the first spray. Arsenate of lead is the spray used, applied at the rate of Hlb. to 100 gallons of water. In applying arsenate of lead sprays, particularly when mixed with sulphur sprays, it is essential that hydrated lime be added at the rate of 3 lb to 100 gallons, to avoid injury to the fruit a.iid Foliage. The second spray should bo applied ten days after petal fall, followed by applications every ten to sixteen clays until the fruit has matured. It may he said that to spray, bandage the trees, and pay strict attention to orchard hygiene is not economical. but when the percentage of first-class fruit gained is taken into consideration it is false economy to neglect these phases of the control of codling molli.