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Investigations or Oil Spkays for Red-mite Control on Orchard Tbees. Preliminary laboratory experiments to test ovicidal efficiency were carried out with twenty-six specially prepared oils on the winter eggs of red-mite. These oils varied in viscosities, methods of emulsification, and percentage of unsaturation. The winter eggs of two species of red-mite were used—viz., those of Paratetranychus piloeus and Bryobia praeliosa. The results obtained showed a striking difference in the killing-power of oils on these two species. B. praetiosa eggs were considerably easier to kill than were those of P. pilosus. Quickly breaking, unstable emulsions were found to be much more effective than were stable, permanent emulsions made with the same oils. The killing-power of stable emulsions was found to increase with viscosity, but with unstable emulsions a 100-per-cent. kill was secured with a considerably lower viscosity. Field experiments demonstrated that winter oils are most effective against red-mite eggs when applied as closely as possible to bud movement in the spring. Experiments have been planned for both the laboratory and the field in which relatively unstable emulsions will mainly be used, but this work is temporarily held up on account of pressure of work in connection with Pieris rapae. Control of Grass-grub (Odontria zealandica) in Lawns, etc. Experiments have shown that for turf a top-dressing of 5 lb. of acid arsenate of lead powder per 1,000 square feet of surface is an effective means of grub-proofing tvirf. Over large areas this quantity might be reduced to 2Jlb. or 31b. per 1,000 square feet to lower expenses, but the effect of the poison will not endure so long. The treatment has effectively kept out the grub for a period of twelve months after laying down, and should be effective for several seasons. Naphthalene and similar preparations when injected into grub-infested turf have proved to be ineffective. Naphthalene dug into soil in which plants are soon after placed is liable to damage them when the dressing exceeds 3 oz. per square yard. Common salt (sodium chloride) has proved useless as a control of grass-grub. Box experiments were made to discover the effect of various manures on the effectiveness of the arsenate control. Superphosphate, sulphate of ammonia, and nitrate of soda were used. None of these impaired the efficiency of the arsenate after a period of eleven months, and there was no apparent detrimental effect on the growth of the grass. Manuring of grub-infested turf gave excellent results. The application of sulphate of ammonia in the autumn almost completely eliminated the damage caused. Further, the experiments showed that manures had no killing effect on the grub, except that calcium cyanamide proved toxic when used in pots but was non-toxic when broadcasted in the field. Again, experiments showed that carbon bisulphide-Restar emulsion will not damage plants in open, grubinfested soil. This emulsion is safe to use on plants growing in cultivated ground during winter. Further work with carbon bisulphide-Restar emulsion has shown that watering on the chemical has no advantage over the injection method, except where it is undesirable to make holes in turf or where plants in cultivated ground are to be treated, in which case the emulsion may be applied more quickly unless a machine is used for injecting. The use of Orach, or Canadian Spinach, sprayed with arsenate of lead again proved to be of no special value in reducing grass-grub infestations. Bronze Beetle. Following on from work previously reported upon, this project had been concluded. The previous work showed the value of the protection afforded young fruits by a complete cover of arsenate of lead. As stated in the last annual report, there is a minimum amount of arsenate-of-lead deposit required for effective control, and investigations with spreaders showed that these materials, while increasing the evenness of the film, were very prone to run too much spray off the fruit. The most effective type of cover that could be secured by spraying was a close " spot " one applied with a fine mist spray using acid arsenate of lead alone. Work with fish-oil and arsenate did not uphold previous results because the oil also ran too much arsenate off the fruit. Paris green gave a better killing effect on the beetle than did the same quantity of arsenate of lead, but the former material is very liable to cause injury. Barium fluosilicate gave approximately the same control as did arsenate of lead, but it too caused severe burning of the fruit. The conclusion reached in this work as far as spraying is concerned is that a good, even " spot" cover of arsenate of lead applied as a mist spray will give a good control, and where the beetle is troublesome it is advisable to endeavour to secure such a cover with 4lb. of acid arsenate of lead per 100 gallons of spray. BOTANY SECTION. EL H. Allan, Systematic Botanist. IDENTIFICATION OF SPECIMENS AND ADVICE THEREON. As in previous years, this work has taken up a considerable amount of time, and the service is increasingly appreciated by inquirers. The interested parties are as classified in my previous reports. Interesting features of the year have been the interest, taken in plants suspected of being poisonous to stock, the number of horticultural specimens sent in, and the attention to species of ecological value as indicator plants of soil and habitat conditions. The number of specimens received was about 4,000, ranging from individual examples to large collections. As one result of this work it has been possible to give timely notice of newly observed weeds likely to cause trouble if allowed to spread— e.g., buffalo bur (Solanum rostratum), horse nettle {Solanum carolinense), saffron thistle (Carthamus lanatus) marsh thistle (Girsium palustre), squirrel-tail grass (Hordeum jubatum). It has been pleasing to note the increased interest taken in these matters by the stock inspectors and instructors in agriculture of the Department of Agriculture. HERBARIUM. Numerous additions have been made to all sections of the herbarium—the indigenous, the introduced, and the exotic plants. Apart from their general utility for identification purposes, and for demonstration to visiting botanists, these collections serve as a basis for much of the systematic investigation carried out by this Section. Special attention has been paid to the grasses, and Mr. Zotov has collected largely the mosses of agricultural

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