CAN PENICILLIN HELP THE FARMER?

New Zealand Listener, Volume 14, Issue 345, 1 February 1946, Page 10

CAN PENICILLIN HELP THE FARMER?

Pioneer Research Planned by N.Z. Scientists NEw developments in the use of penicillin and similar preparations may arise out of research which is to begin early in the New Year at the Plant Diseases Division of the Department of Scientific and Industrial Research, in Auckland. Laboratory investigation will be directed at the isolation of good strains and when these are available they will be produced on a large scale at the Plant Chemistry station at Palmerston North. The aim is to discover if these extracts, known to science as anti-biotics, can be used to control or cure plant and animal disease. In the control of plant diseases, this is a new field and, as far as is known, has not been investigated overseas. What the farming industry may gain from the projected studies will not be known until long and complicated experiments,are carried out, but at least New Zealand has got off to a good start.

HE cultivation of Penicillium notatum-the mould which produces penicillin-and the study of variations in its characterist\es have already begun in the bacteriological and mycological departments of the Auckland plant research station, but once the necessary organisation has been completed the work will be shared between Auckland and Palmerston North. The necessary micro-biology wilk be done at Auckland and the Plant Chemistry branch will handle the chemical and the production sides. Large-scale) production will not be difficult since, as one of the Auckland investigators pointed out to The Listener, the growing of penicillin and the brewing of beer have much in common. At this stage it can’t be said just how the field investigations will shape but the testing of anti-biotics on animal diseases will probably be done at the Government’s experimental station at Ruakura, Hamilton. For the control of plant diseases, the possible value of building up concentrations of antibiotics in the soil is likely to be investigated at Auckland. But that is only one of the many techniques which will be tried. In the initial stages the work in micro-biology will be of particular importance, since it will show which varieties of anti-biotic may safely be used. Some are as deadly to man as penicillin is to certain bacteria. Ships and Shoes and Sealing-Wax Ships and shoes and_ sealing-wax would seem to have as much in common as army tents, breweries, passionfruit and penicillin. Such a string of misrelated subjects sounds more like the attempts of a viva-voce psychologist to probe a deep-seated and elusive neurosis than the course of an orderly conversation. But variety like that is quite logical and natural if you are talking ‘to the Plant Diseases people. The four topics mentioned (exclude, of course, the Walrus’ table talk) arose in the course of a brief conversation which The Listener had with the bacteriological and mycological experts, and the common denominator of the four was fungus, which is the subject a mycologist is interested in. . That same ‘variety gives some indication of thé complexity of the work these

men and women do. For the Division is concerned with more than finding cures for the blights and bugs which plague the farmer and the market gardener and the orchardist. Its work ramifies into all sorts of unexpected corners and the experts are constantly being asked to solve problems, in the processing of plant products, which get further and further away from the plants themselves. Back Room Brains Trust Like the other Divisions of the Department of Scientific and Industrial Research, Plant Diseases has its own sub-sections and specialists--in entomology, mycology, bacteriology, virus diseases, plant physiology, horticulture, timber preservation and therapeutants (chemical treatments, such as sprays). And, in effect, the group is a full-time practical brains trust. You may read their names from time to time on the title pages of scientific publications but you won’t see them very often in the daily papers, for while they form a brains trust they do not broadcast much. They are essentially back-room boys. Occasionally their work behind the scenes reaches the public. There was the mould on the ceilings of some State houses which caused irritation to many housewives (and a lot of worry to the Housing Department) a year or two ago.

The mycology and timber preservation sections solved this problem, for the cause of the stains was a fungus organism. Of course, it wasn’t solved just like that. First of all they had to isolate spores of the fungus which was causing the trouble-a difficult job in itselfthen colonies of these had to be reared quickly in incubation chambers, and various chemicals tested to find one which would prevent the fungus growing without having any bad effect on the plaster-board on which it appeared. It was found that the fungus could not be eliminated .during the manufacture of the board and both painter's size and wallpaper paste provided it with all the food it needed to thrive. A small amount of chemical, added to the paste and size, was the simple solution of the problem. When it was added in the proper way, the fungus was unable to grow and the Housing Department breathed freely again-or as freely as it usually breathes these days. Speeding Up Nature 4 Another instance in which the Division did a quick job during the war years was in finding means for preventing the rotting of tent canvas in the tropics. Here again the urgency of the (continued on next page)

(continued from previous page) SOS demanded a speeding up in natural processes, for in this country, fortunately, canvas won't mildew and rot unless it’s exposed for months. And results were needed much quicker than that. Once more spores had to be isolated and cultivated. Pieces of canvas treated with colonies of spores were placed in special incubators where heat and humidity reproduced the quick-rotting tropical conditions. Finding a chemical which would stop the growth of the fungus and at the same time remain effective when exposed to tropical weather was a headache, but one was finally discovered and as a result of this work thousands of American soldiers in the South-west Pacific bivouacked more comfortably and healthily than ‘they might have done. But often such investigations have to wait the slow turn of the seasons before the efficiency of remedies can be proved. A slow-motion battle of this kind was carried out during the years 1936-38, when disease almost wiped out the passionfruit orchards of the North. The organism which caused all the trouble was one peculiar to New Zealand and the research workers had no fund of overseas experience to draw upon, But by 1943 they had found a copper spray which reduced the percentage of infected fruit from over 90 (at which point the entire crop could be written off) to less than five, which, on the other hand, could be regarded almost as normal wear and tear. And so we can still get passionfruit to put the finishing touch to the Christmas fruit salad. You Put This in Your Pipe But in spite of the heartening news of: successful skirmishes with blights and bacteria, some of the statistics we gathered plunged us in the deepest melancholy. Take the virus diseases, for example, which are caused by tiny, submicroscopic forms of life-in fact, they seem so close to pure chemical compounds as to make no difference. Outside of a few experimental plots, there is probably not a virus-free potato in the Dominion and virus alone takes an annual toll of the potato and’ tomato crops. -which is probably as high as 20 cent, ;

Or are you finding it hard to get tobacco? . You can blame the mosaic virus. It keeps the local crop about 25 per cent lower than it would be if this trouble could be controlled-and a 25 per cent increase in the local supplies would go a long way to meeting the demand. But mosaic virus, which can be transmitted by the juice of infected plants, is universal in its scope. It can stand a temperature of about 90 degrees Centigrade and it will therefore survive most curing processes. In fact, you are continually putting it.in your pipe and smoking it. The only way to fight the virus diseases seems to be to develop resistant strains of tomatoes, potatoes and tobacco, and so on. Good work has been done by the Agronomy Division at Lincoln in cultivating resistant strains of green peas for the growers at Blenheim, where there is a fair export trade to Australia in seed, but. where there is also a lot of pea mosaic virus. The

"Greenfeast" pea, which is most favoured by the Australian buyers, is unfortunately susceptible to the mosaic but collaboration between the Agronomy Division and the Plant Diseases Division has resulted in the cultivation of numerous strains of "Greenfeast" pea which look as if they will be fully resistant. The same thing is being done in the much more important field of swedes and turnips, also the victims of a mosaic. Unfortunately the varieties which have proved resistant to mosaic, club-root and dry-rot are also resistant to stock, and a more palatable variety will have to be evolved. Busy Little Borers It was a relief to drop into the timber preservation section, where the job is the straightforward one of fighting borer. It happened to be the busiest time of the year for the workers there, for our visit coincided with the flight season of the adult borer-beetle and at that time of the year about 20,000 beetles are handled, sexed and mated to provide the new season’s stock of eggs. In the decent privacy of small thimble-like shelters, the broody females lay their eggs on a square of white gauze stuck on to a small square of wood and, since the life-cycle of the borer is three years in white pine and four in matai or rimu, every care is taken to give them a good start in life. The Plunket Society couldn’t do it any’ better. Borer control research proceeds along two distinct lines. The control of the pest-in existing buildings it is the most serious enemy of building timber in this country-is one half of the work. It. is almost impossible to eradicate the larvae but it can be prevented from spreading by chemical means. The current research aims at finding a contact poison which will remain toxic on wood at least as long as the life-cycle of the insect. The other line of investigation is to devise some way of treating timber before it is used by impregnation of the wood fibres. In a vacuum, solutions can be driven right through timber but the wood is left very wet and at present experiments are being carried out in which air pressure is used to impregnate the wood. When pressure is released, the air driven into the wood expands and blows out the surplus moisture. Complete treatment, right through the wood, has not yet been achieved with this method due to air originally in the wood building up in the centre under oe high pressure. But by the time most of us Pes round to pulling down our old barns (or houses) and building new ones we should at least have the consolation of knowing that, though moth and rust may still corrupt, at least the borer will no longer be able to cut the floor from under our feet.