408 



THE GARDENERS' CHRONICLE. 



[June 22, 1912. 



ROYAL mTERrfATIOtfAL HOR- 

 TICULTURAL EXHIBITION. 



LEGISLATION IN CONNECTION WITH 



PLANT DISEASES AND PESTS. 



At the conference on Friday, May 24, the Right 

 Hon. A. H. Dyke-Acland, in opening the proceed- 

 ings, said now that lu^f had recognition of 

 horticulture by the State, it was for them as time 

 went on to try and work upon that beginning 

 and develop, so far as they could, the initial 

 steps which had been announced by Mr. Runci- 

 man on Wednesday, May 22. 



A paper on " The Value of Importation Regu- 

 lations as a Means of Preventing the Introduc- 

 tion of Plant Pests from Abroad M was read by 

 Prof. Ritzema Bos, of the Phytopathological In- 

 stitute, Holland. He said it was a natural 

 consequence of world traffic that animal and 

 fungous enemies of agriculture and horticulture 

 were sometimes transported with the plants on 

 which they lived from one country to another. 

 Thus two very dangerous enemies of the vine, the 

 Downy-mildew (Peronospora viticola) and the 

 only too well-known Phylloxera vastatrix had 

 been successively transported from America to 

 nearly all vine-growing countries of the Old 

 World. Similarly in recent times the serious 

 American Gooseberry -mildew had come from 

 America to Europe, where it had spread over 

 several countries in a short time ; and also the 

 not less grave San Jose Scale had been carried 

 from one State of the American Union to 

 nearly all others, and the authorities in several 

 European countries, too, feared its intro- 

 duction. In like manner the Gypsy Moth and 

 the Brown-tail Moth were transported from 

 Europe to America ; and last, but not least, the 

 Potato u black- scab' * was spreading in every 

 country where the diseased tubers were brought 

 by trade and heedlessly planted for seed. Now 

 the question suggested itself : in what way should 

 a country guard against the invasion of injurious 

 animals and plant diseases from abroad? 



The answer seemed simple. When some very 

 injurious organism feeds on a certain plant in a 

 certain country, care should be taken not to 

 import from that country specimens of the plant 



or parts of it. 



While not absolutely dissenting from the idea 



of prohibitive regulations, he drew attention to 

 some difficulties connected with those measures, 

 and showed that in most cases they only repre- 

 sented a sad misuse of both labour and money. 



As to the difficulties, he touched on the prin- 

 cipal ones. To-day one pest, to-morrow another, 

 menaced our country from abroad. Again and 

 again new prohibitive orders would be necessary 

 in every country. Till the several States would 

 become almost entirely isolated, much to the cost 

 of their trade, their culture; in short, of their 



whole life. 



Often the insistence on prohibitive measures 



was not free from protectionistic inclinations. 

 Interested persons were anxious to find pests 

 or blight on the stock of competing countries in 

 order to have a pretext for asking the Govern- 

 ment for a prohibitive order. 



And the results of the importation regulations 

 —were they proportional to the expectations 

 they raised? No, indeed! 



In the first place, they were nearly always 

 issued too late. Not until a certain pest seri- 

 ously damaged our crops, and not until the news- 

 papers interfered with it, as a rule, did the 

 Governments make up their minds to do some- 

 thing. So between the intention and the issue 

 of a Governmental order much time passed, and 

 when busy commercial relations existed between 

 the country where the pest was feared, and the 

 country where it had got a firm footing, no doubt 

 it would steal across the boundaries long before 

 the order had come into force. That the San 

 Jose Scale had not hitherto gained footing in 

 Europe was not because of the prohibitive mea- 

 sures enacted in several European countries con- 

 cerning the importation of American stock. The 

 difference in climate, in soil, in cultivation, fur- 

 nished reasons why it could not thrive in these 



regions. 



He was not an absolute opponent to prohibi- 



in 



that which 



tive orders as a method of checking pests. All 

 diseased plants when discovered should be 

 burnt. Dealing with the question — could in- 

 spection of the port of landing be relied upon, 

 he answered " No ! " He set upon it more value 

 when it was combined with disinfection. There 

 should be inspection and certification of health 

 before exportation. In no other way could 

 disease be prevented. But this inspection only 

 gave what reasonably could be required of it — 

 a guarantee for the health of the stock — 

 when a well-equipped phytopathological service 

 existed in the country from which it came. 

 Summing up, he stated that the best guarantee 

 against the importation of plant diseases and in- 

 jurious animals was given by the combination of 

 two measures : First, certificates of health, de- 

 livered by the State phytopathologist of the 

 country of origin, and required for each imported 

 consignment; secondly, inspection and, if need 

 be, disinfection executed before the consignments 

 were accepted by the consignee. 



Only in very exceptional cases prohibition of 

 importation was to be adopted as a method of 

 preventing the introduction of pests; but this 

 method was not at all to be relied upon as a 

 never-failing expedient. 



Mr. A. G. L. Rogers, Intelligence Division, 

 Board of Agriculture and Fisheries, in his paper, 

 said the real danger to be feared in this countr 

 was of a very different order fr< 

 beset more extensive countries, especially those 

 which were still thinly populated, where farms 

 were large and means of communication still im- 

 perfect. In an old and densely-populated 

 country there were few localities which were 

 not under cultivation of some kind. The area 

 classed as mountain and heath in England was 

 very small, and though the districts covered by 

 towns were large and numerous, there were gar- 

 dens attached to the houses among the mountains 

 and in the towns where fruit and vegetables were 

 grown which might harbour diseases and pests 

 and render the task of extermination correspond- 

 ingly difficult. Even in the districts that could 

 properly be described as agricultural there were 

 no natural boundaries which would check the 

 spread of disease, while the means of communica- 

 • tion by human as well as natural agencies were 

 rapid and easy. The fact that pests were re- 

 garded as serious in countries with which Eng- 

 lish nurserymen trade was one which the Board 

 were bound to take into consideration. In recent 

 years British colonies and foreign countries had 

 imposed regulations dealing with the importa- 

 tion of plants which rivalled in number and hard- 

 ness the rules called the Pie, and it was to be 

 feared that in some cases nurserymen had aban- 

 doned their overseas connections on the ground 

 that the trade was not worth the trouble involved. 

 It would probably not be contended by anyone 

 that it was the duty of the Government to push 

 the business of any particular trader, or even the 

 business of any class of traders, except in a 

 general way. Those who made private profits 

 must depend on their own exertions and the 

 reputation which the high quality of the goods 

 they offered brought them. But it might reason- 

 ably be urged that it was the duty of every 

 Government to smooth away the difficulties 

 which other Governments laid in the path, and 

 that the Board should help exporters to surmount 

 the barriers imposed on importation when they 

 could properly do so. With this object, the 

 Board had been at some pains to collect and 

 publish as complete a collection as possible of all 

 the regulations in force in other countries deal- 

 ing w T ith the importation of plants. A study of 

 these regulations showed that they might roughly 

 be divided under three heads, namely, those 

 which required that the actual plants to be im- 

 ported had been inspected by an officer of the 

 Board and were certified to be healthy ; those 

 which required that the plant should come from 

 a nursery which had been inspected by an 

 officer of the Board and declared to be free from 

 disease ; and those which required a certificate 

 that no case of certain specified diseases had 

 occurred within a certain distance of the place 

 where the plants were grown. The utmost that 

 the Board could do was to ascertain the nature 

 of the regulations and offer the nurserymen 

 facilities for complying with those that required 

 some inspection or report as regards the freedom 

 from disease of that part of England from w T hich 

 they came. Arrangements had accordingly been 

 made for such inspection and the issue of such 

 certificates, and a memorandum setting out what 



the Board were prepared to undertake had been 

 circulated to all the principal nurserymen in 

 England. It was in order that the Board's in- 

 spectors might be in a position to enter 

 premises where disease might exist and search 

 all places where it might be found that the pests 

 recently referred to had been scheduled, for in 

 some cases at any rate it was necessary to 

 examine not only the premises or the plants in 

 respect of which an application for a certificate 

 had been made, but the adjoining premises as 

 well. There were few, if any, pests that could 

 be introduced from or into countries with a 

 temperate climate that would breed or spread 

 to neighbouring plants so rapidly that they could 

 not be readily stamped out. In the case of the 

 few pests to which that did not apply the intro- 

 duction of the host plant should be prohibited 



altogether. 



Mr. H. M. Lefroy, M.A., F.E.S., F.Z.S., Im- 

 perial Entomologist for India and Lecturer in 

 Economic Entomology at the Imperial College of 

 Science, London, in his paper said the problems 

 of legislation in regard to checking the importa- 

 tion of insect pests to tropical areas had as yet 

 received little detailed attention, and, while this 

 was largely due to the fact that many tropical 

 colonies were only partially developed, it might 

 also be due to the belief that insect pests were 

 little likely to be introduced, and that, if they 

 were, they would not become established or live 

 under tropical conditions. Greater attention was 

 now being given to the development of tropical 

 agriculture and horticulture, and the study of 

 the pests that affected plants in these areas was 

 showing that the problem was an important one, 

 which should not be neglected either in the in- 

 terests of the growing industries on the spot or 

 of the existing horticulture of Europe and other 

 temperate regions. The dangers were perhais 

 mainly from scale insects, insects that live in 

 tubers or roots, fruit-flies, such insects as weevils, 

 which could endure long fasts, and aphides, in 

 which reproduction was reduced to so simple a 

 business that one egg sufficed to establish the 



It should be 



race. 



The lesson of the past was clear, 

 possible to prevent a recurrence of such cases as 

 the Potato Moth, Woolly Blight of the Apple, 

 Boll-weevil, San Jose Scale, and the like. In his 

 view, they should be awake to the danger and 

 should be taking steps to meet it. It was deplor- 

 able to see countries fencing themselves blindly 

 with indiscriminate prohibitions, fumigations, 

 quarantine, inspections, &c. They wanted to 

 move towards a common basis of legislative 

 action, upon which was built the measure adapted 

 to the needs of each area, a necessary preliminary 

 to that being a far wider knowledge of the 

 dangers that existed, so that our legislation might 

 be framed against them. Progress towards 

 reasonable legislation would be made when the 

 pests of all countries were known. What was 

 wanted was a survey of the pests of all areas in 

 which plants were cultivated; to know of new 

 pests, how far they were likely to spread, 

 whether they were likely to be imported and on 

 what. To know this, the pests and their habits 

 must be known, and those of many of our cok-nies 

 in the tropics w T ere not known at present. 



An entomologist, with a list of the pests ox 

 any country and their food-plants, should be able, 

 with some knowledge of their habits, to see wnicn 

 of those were likely to become established in ms 

 area, how they might be introduced, and how to 

 guard against them ; in most cases very few were 

 likelv to be carried by commerce at all, and tee 

 knowledge we had of "the spread of pests showea 

 that there were special cases which could be tairi 

 easily guarded against provided one knew o 



them. _, l 



Mr. H. T. Giissow, Dominion Botanist, I^P a £ 

 ment of Agriculture, Ottawa, Canada, said tne 

 onlv practical means of obtaining results iron 

 legislation would be the co-operation of expeiu 

 assisted by farmers, gardeners, fruit g rQ y e ^j 

 produce importers, and representatives ot 

 other industries affected by such measures, 

 were nowadays much concerned about quest 

 of international peace and goodwill, but it ap- 

 peared that notwithstanding international agn? 

 ments regulating commercial and trade re lal ? w 

 of countries, that one main point was lost ag 

 of— the malpractice of exporting diseased vegei 



It seemed a surprisingly ludicrous powjj ►j 

 countries willing: to spend millions to co , 

 diseases within their own borders distributee! ^ 

 very same disease all over the world without 



tion. 



