FUNGICIDES.

Otago Witness, Issue 2622, 15 June 1904, Page 10

FUNGICIDES.

Phe word fungicide is made up of two parts — "fungi," 'the plural of fungus, and "cid'e,"^ to kill. The substances that are used 1 are such as will (kill fungi, and not kill the host plant. The history of fungicides shows that they were all discovered by accident, but lha£ latterly systematic efforts have been put forth to perfect these and to discover new ones. A fungicide, to be of practical value, must also be of moderate cost, or it will cosb as much to save a crop as the fruit will bring after it is matured. The item, of applying is one of considerable cost, therefore good men and efficient appliances are required to enable the greatest amount of spray--hig consistent with efficient work and economy to be accomplished. Spraying at 'best is laborious and disagreeable work, and unless done thoroughly and at the proper time is little better than if not dono at all. It becomes of prime importance to know when to spray. A fungicide merely prevents a plant being attacked by certain Fungi ; the fungus mycelium enters the host plant from 4he outside, therefore we place upon th© host plant a poison (fungicide) which kills the spore of tlie mycelium ; but the mycelium once within the host is beyond the reach of the poison, and will continue to grow and reproduce its kind. From this it will be seen that a fungicide does not cure, but prevents ; therefore the good old adage, ''an ounce of prevention is better than a pound of oure," mu3t be the motto of the .grower who. is" desirous 1 of controlling the dis&ases due to the attacks of fungi. As a .general rule an orchard should be sprayed ' with a fungicide before the buds open, again after the bloom falls, and then at intervals of about ten days. The number of 'times to spray will depend greatly on atmospheric conditions. During dry weather most fungi are not able to infect their host plants, and it, is said the disease does not spread. Moist weather brings about good conditions for fungi to spread, and at the same time rain frequently washes off a considerable quantity of the fungicide. Hence we require to spray often during rainy weather, and not so frequently in dry weather. The time and method of application of the spray are so -essential that no result of value can ba hoped for unless these details are observed. The work must be thoroughly done. Any portion of loaf or Dranch not covered with the fungicide is liable to be attacked. The amount of material applied should be just enough to form & fine film over the leaves and branches,- not so much as to drop from the plant; ihenc© the best spraying-nozzles for treating the foliage and branches are those which reduce the fungicide to the finest mist. The cost of fungicide or insecticidal treatment includes the original equipment, that of the materials consumed, and that of tlie preparation and application. The points to be remembered are to select a suitable fungicide or insecticide, to select the proper time to spray, and to apply thoroughly. Previous to the use of remedies it -is of the greatest importance that old trees should be prepared for direct treatment by pruning out all superfluous branches and reducing to such size as will the work of spraying to be performed with ease and expedition. It •is also advisable that the trunk and main limbs should be cleaned of rouglr bark. It stands to reason that it is not possible in the limits at my disposal to speak specifioally of all pests of the orchard so as to give detailed instructions for spraying to combat each. Sufficient to say that in general -work we spray for several specific objects; that the time to apply and thebesb stage for the first spraying to combat the various fungi is just as the clusters of fruit buds aTe pushed out andf before the petals have expanded; the second application immediately after the bloom falls; the third about the time that the foliage is fully out and the new growth of the season well started. The igeneral treatment outlined covers the ground quite effectually, and serves as a basis for ordinary work. Still, there may be circumstances in which further spraying may be advisable. However, the large number of sprayings 'recommended by some writers are in the main unnecessary. Perhaps th© preceding and following details may seem unimportant and tedious to many ; nevertheless, they are some of the little things which, when neglected, may often prove the main cause of failure. The following summary gives in concise form the essential points in regard to the preparation and use of the several substances used as fungicides and insecticides : — Sulphur. — This is probably one of the first substance which was used as a fungicide-. It is used in the form of a powder, known as flour of sulphur, in the finest state of division post- ~ihle. All that is necessary is to dust it I ove? tie. vlitils afFcetci. Tts rrnujif.al uso is i;i conlUktßay,' raildew ol ibo grape- "vine. — {rtver of Sulplm? {|^ta?9ium Sulphide).— In the proportion of Jc% *^*J ie i S*ttvnof water, this is applied a3 a epray ~tC- .coasnbat mildew of the grapo vine and otlie* , plants. Or it may b© applied directly to the soil which needs treatment for dampingoff IwikL Tho substance should be kept

in stoppered boifles until wanted 1 , when it should be dissolved in a wooden vessel and then applied. Besides its general properties as a. general fungicid© it is also useful as an insecticide for thrip, red spider, bryobia or red mite, also plytops. Liver of sulphur can be purchased from any drug store.