LECTURE BY MR J. C. BLACKMORE.

Otago Witness, Issue 2896, 15 September 1909, Page 10

LECTURE BY MR J. C. BLACKMORE.

FRUIT TREES AND SPRAYING. The last of a series of lectures on horticultural and kindred subjects was given in the Technical School on Wednesday by Mr J. C. Blackmore, Government Pomologist. The lecture was given under the auspices of the Dunedin Horticultural Society, and there were a goodly number present, including several of the fair sex. The subject of Mf Blackmore's lecture was " Fruit Trees and Spraying," and by reason of his extensive experience the lecturer was able to afford much useful information on the subject- of fruit-growing lind the best methods of coping with the various insect pests incidental to fruit trees. Mr Thomson introduced the speaker with a few remarks, in the course of which he mentioned that Mr Kirk, the Government Biologist, had reassured Tasmanian potato-growers by stating that the potato blight, which had recently caused such damage to the tuber crop, oould be suppressed by judicious spraying. The lecturer emphasised the value of spraying fruit trees, and, referring to the most approved methods, he said that for holding fungous disease under control Bordeaux mixture was recognised as the best preparation. At first the mixture consisted of 61b of copper sulphate and 41b of slaked lime, mixed and diluted to 25 gallons, but this had since been modified. Mr Blackmore then gave explicit directions how to make the mixture, the desideratum being the absence of free sulphate of copper, and pointed out that it should be used when freshly made. He also adverted to the modifications of the original Bordeaux mixture in use, such as clear saturated lime water, the washing soda Bordeaux, the caustic soda or potash mixture, and the soap mixture. The 4-5-40 formula consists of 41b bluestone, 51b unslaked lime, and 40 gallons water. The constituents of the washing soda mixture are 61b sulphate of copper, 91b washing soda, and 50 gallons of water. The lime" water mixture is made from lib sulphate of copper dissolved in one gallon of weter and 13£ gallons of clear saturated lime water. A substitute for the Bordeaux mixture, called the carbonate of copper mixture, consists of the following ingredients: — 3oz copper carbonate, one quart ammonia, and 25 gallons of water. Having indicated the ingredienfcs and the methods of preparation, which ■were very minute and lengthy, Mr Blackmore proceeded In conclusion to describe the mode of application. He said : "Having the mixture properly prepared ano' thoroughly agitate- 1 cannot alone ensure success; unless the spray is properly applied all preliininai-y effort is lost. Firstly, it will be noticed that Bordeaux mixture consists of material suspended in water and applied while in suspension It is highly important, therefore, that the agitation of tne mixture be most thorough in order that the material may be equally disseminated through 'mt the h i .id, for unless it is two evils will result. The first portion will be too weak to do effective work, and the last will be so strong that the trees will be injured, and especially will this take place under certain unfavourable weather conditions, as previously explained. In order to obtain satisfactory results the whole of the tree under treatment must be wetted — that is, completely cmered with the urxture — from the top most twig downwards to the ground line ; therefore, in order to spray to the best advantage we must have a fine spray ; use only a fine nozzle ; use force enough to keep the liquid issuing as a fine mist, and spray only until the foliage and fruit are completely bedewed, and not until everything is dripping. The exact time of application is of tihe utmost importance. 1 have long since come to the conclusion that for the suppression of the curl leaf fungus of the peach, shot hole fungus and scab of apricot, black spot or scab of apple and pear, the application of Bordeaux mixture should be made at the period a little before fche opening of the bloom that is just after theblossom buds are plainly in view. The failure of the ordinary .spray iag with Bordeaux^ mixture for apple and pear scab is largly due because applied too late, whe-n it has no effect. The idea must be to kill the scab developing on the bark and buds as the latter begin to swell, and not on the young apples or pears after they have formed. For very thorough results, itis wise to spray twice before the blossoms haw opened. Firstly, when the blossoms are slightly swollen and showing just a tinge of colour. Secondly, before the whole of the blossom buds have unfolded — that is. before full bloom or about a week or 10 days after the first spraying. The object sought to be attained by* these two spiayings at the particular periods indicated U. that there appears to be a definite brief time of development of the fungus occuriing simultaneously with the development of the blossom buds. The application of the fungicide at or about the periods mentioned checks the fungus for the whole season. A +huxl psrayimg may be applied as foon as the petals have fallen, and if codlin moth is prevalent arsenate of lead may be added to it. But the two first sprayines as suggested, should be depended on as being the most effective for holding the fungus under control. I should point out in reference to apple and pear scab ' that it has two stages in its life history; during the growing season, it lives as a parasite on the fruit leaves and other growing parts of the tree, but durinp -winter it lives as a saprophyte on the dead apple leaves and twigs. It is from these latter sources it starts again during spring The gathering up of twig and leaves as soon as fallen and burning, or by ploughing in, materially assist to keep this fungus in check. I hay« tried to give some of the important points with reference to preparing and applying Bordeaux mixture, a.n*l conclude by etating that, environment

' and weath**: conditions are important elements to be reckoned with — bufc the men who do tfte work much more so. At the conclusion of the lecture Mr Blackmore was greeted with hearty applause. The Chairman remarked that the lecture was a very valuable one. and he hoped thosepresent would profit largely. He referred to the valuable services given in the past by Mr Blackmore, and he regretted that the exigencies of the retrenchment scheme had affected the lecturer along with others in that department. In answer to a question, Mr Blackmore remarked that he could not reoommend a«y Bordeaux mixture or similar preparations sold in tins, as none of them was equal to the mixture freshly made just prior to use. A gentleman present remarked that he had obtained excellent results by giving youn-g trees a slight coating of kerosene and also by spraying with Bordeaux mixi ture, made with soda and 6ulpbate of copper. This was found to be very effective j for fruit treee and also potatoes. Mk Blackmore deprecated the use of kerosene, and explained that serious results [ usually followed its use. A diluted solution of the Bordeaux mixture was efficacious for roses, but was nofc a preventive' of the borer in raspberries. He recommended I the salt and lime solution for removing ! mussel scale and fish oil soap solution for spring wash when soft bedied insects are : ojj the move. Mr Sonntia^g paid a warm tribute to the services rendered to fruit growers by Mr Blackmore, and owing to the large areas now being placed under fruit trees in Otago, it was greatly to be regretted that the Govenwnient had seen fit to dispense with his services, and he thought steps should be taken to have his services retained for the benefit of a valuable young industry such as fruit growing. At the close a very hearty vote of thanks to tfee lecturer was carried by acclamation. On the motion of the Chairman, hearty votes of thanks were accorded -all those who had given lectures during the winter, and a hearty vote of thanks was also accorded the Horticultural Society for affording- pleasure and profit by giving 6uch a fin© s«ne« of lectures. j