1.32 pounds of this lime were used for each pound of unslaked lime called for in formula. The sulphur compounds were applied August 7th-11th. Heavy rains fell August 12th-16th and with the object of determining the effect this had on the recently applied washes the tests already started were duplicated on new sets of trees when the remaining washes were applied August 16th-22nd. Examinations were made about once a fortnight up to the first of the year, and subsequent ones in late January and early March. More frequent inspections were impracticable owing to the distance of the scene of operations from the office. Hex River station is about 125 miles from Cape Town, and the orchards a few miles beyond. The full strength resin wash and the arsenic preparation caus, d some gumming from the bark, but this injury appeared to be soon overcome. The washes containing lime retarded the development of the buds by a few days, and those which darkened the bark, including all the soap washes, paraffin emulsion and resin wash, accelerated it; the trees done with the strongest whale oil soap wash were in full leaf at least twelve days ahead of untreated trees. However, as the season advanced, even the most backward trees appeared to catch up with the most forward. The setting of fruit seemed unaffected by the washes, and was quite satisfactory. Only the egg stage of the mite was present at the time of the spraying, and not anyone of the washes seemed to have any appreciable effect on it. The eggs were deposited amidst old shells, and many both on sprayed and unsprayed trees failed to hatch, and hence it was impossible to make close comparisons; but a careful inspection a few weeks after the spraying gave the impression that the strongest soluble sulphur, soap, resin and paraffin emulsion sprays had destroyed a small proportion of the eggs. The eggs began to hatch in the middle of September, and at that time it seemed as if all the washes were failures. But from the experience of previous years, we knew to expect good results from the soluble sulphur washes at least, and hopefully continued the observations. The young mites swarmed in myriads about the swelling buds, and appeared to feed through the thin bark of the twigs as well as on the young foliage. Eggs were still hatching October 10th, but by this time the results of the spraying were becoming strikingly apparent. The mites had almost disappeared from the trees sprayed with the strongest lime-sulphur-salt, lime-sulphur, and soda-sulphur washes, and had greatly diminished in numbers on the trees treated with the more dilute washes of these kinds; whilst on the trees sprayed with all the other mixtures the mites appeared almost if not fully as numerous as on the unsprayed trees. This relative condition was maintained throughout the season. Eggs from the new generation were laid late in October; some were found to be hatching ou November 1st, and by the 11th nearly all had hatched. In early December eggs were again found in abundance, and also mites in every stage of growth. But up to January very few mites were to The trees sprayed before the great storm of August 12th-16th with the sulphide washes remained almost as well protected as those sprayed later until about December. Then it was observed that the earlier sprayed trees were becoming more infested than the later sprayed ones; and, curiously, the increase of the pest was more marked on the lime-sulphur-salt than on the lime-sulphur sprayed trees. The soda-sulphur washes gave results somewhat inferior to and less lasting than the other two sulphides. Soda-sulphur is more expensive, though more easily prepared, and is more disagreeable to apply owing to its greater causticity. Only the strongest sulphide washes, that is those that were made with twenty pounds of sulphur to fifty gallons of water, were considered satisfactory. The weaker strengths were greatly superior to resin wash, paraffin emulsion, and the soap washes; but too large a proportion of the mites escaped for them to be considered really successful. The results reached justify the emphatic recommendation of the lime-sulphur wash as a winter spray for the Bryobia Mite. This wash is nothing more than double strength lime-sulphur sheep dip. It is made by boiling twenty pounds of sulphur, with ten pounds of unslaked or the proportionate quantity of slaked lime in water, until a complete solution of the sulphur is effected, and by then diluting the preparation to fifty gallons. It may be applied hot or cold, but should not be allowed to chill when concentrated as a precipitation of crystals then takes place. The "ooze" may be rejected or stirred in. The spraying should be very thoroughly under pressure from the pump heavy enough to drive the liquid into every crack and crevice of the bark. As the action is almost entirely on the mites themselves, not on the eggs which alone are present in the winter, the spraying should be done as late as is practicable. SUMMER REMEDIES. It was obviously desirable to ascertain what wash answered best against the pest when the trees were in foliage, and with this object in view, applications of various preparations were made, December 12th and 13th. These preparations were: lime-sulphur wash, ten these amounts to 150, 225, 360, 525, 900, 1,500, and 2,250 gallons of cold water; hard soap at the rate of one pound in six gallons of water; paraffin emulsion of Riley-Hubbard formala diluted with nine, and fifteen, parts of water; resin-soda wash (24 pounds resin, 5 pounds caustic soda, and 100 gallons water) at full, half, and quarter strength, tobacco infusion from roll tobacco at the rate of one pound to three, and one pound to six, gallons of water; and "Odamine," a tar product sheep dip, diluted with ten, and with twenty, parts of water. The soap mixture killed all the mites that were hit; so apparently did the stronger paraffin emulsions but at the next inspection many mites were still found on the trees. The full strength resin wash did capital work, and the half strength did fairly good work: but the quarter strength and the weaker paraffin emulsion were both unsatisfactory. The stronger tobacco wash considerably decreased the pest but it did not wet well. The weaker was unsatisfactory. These contact destroyers all seemed to do best when applied in a fine spray through cyclone nozzles. The Odamine at both strengths was effectual in destroying the mites, but injured the foliage and fruit. The lime-sulphur washes were efficient in proportion to their strength. None injured the foliage or fruit. Some mites were destroyed at once by the strongest wash, but in general the good results appeared gradually. On Christmas very few mites were found where the strongest wash had been used, and no great number where the second strength had been. The weaker strengths had done some good but not enough for satisfaction. The results show that several washes may be successfully employed against the Bryobia mite in summer. The lime-sulphur preparation at the greatest strength tested commended itself most highly to Mr. Mally, and is the one we would recommend; this strength is one-third that used during the winter. It may be well to add that no sulphur washes should be cooked in copper kettles nor sprayed from copper knapsacks. 13 ON THE BEHAVIOR AND REACTIONS OF LIMU- BY RAYMOND PEARL. [Reprinted from THE JOURNAL OF COMPARATIVE NEUROLOGY AND PSYCHOLOGY, Vol. XIV, No. 2, April, 1904.] |