43

H.—29

BIOLOGY SECTION. REPORT OF THE BIOLOGIST. The Director-General. Wellington, Ist June, 1920. I HEREWITH submit my annual report on the main lines of work carried out by this Section during the year ended 31st March last. A. H. Cockayne, Biologist. Visit to the United States. I left New Zealand on Nth August, 1919, and visited the United State's, returning em 14th February, 1920. During this period Mr. R. Waters carrie-el out the duties of officer in charge of this Section with ewery satisfaction. To him anil to all the other members of my stall I give my sincere thanks for (he very capable way in which they carried out their various duties during my absence. In the four and a half months spent in the United States I was enabled to visit many of the, agricultural institutions in the west, middle west, and eastern States, devoting myself mainly to a study erf agronomical conditions from tint Standpoints of education, research, and extension. Seeds and Seed-testing. The seed-testing branch of my Section continues to grow steadily, and during the year over eight thousand samples were analysed for germination and purity. While in the, United States I paid considerable attention to seed-teßting methods in vogue there, and also studied the effect erf many of the seed laws that are in operation. With regard to seed-testing great care is taken that lines reported on arc extremely carefully sampled. This is a matter requiring considerable attention mi (he pail ol merchants here. Many if not all the- discrepancies arising in the germination of such seeds as cocksfoot, Chewings fescue, and the' like arc due to lire sending into the laboratory of sample's carelessly sampled and not truly representative of the line in question. I found this same delect had been quite common in the seed-testing work of many of the States, but seed-merchants there now recognize that the laboratory test is true only of the sample submitted, and if not sampled properly may give quite an errone;ous result so far as the whole line is concerned. Very special emphasis is given in the United State;s on the control of imported seed, and unless lines conic within the standards of real value — i.e., certain definite percentages of purity and germination such seed is not allowed ter be sold. Some similar method of control of imported seed should operate in New Zealand, and this phase, of the question has been embodied in a Pure Se'i;ds Bill which has now be;em prepared. During the year very considerable losses have been suffered by merchants in the export from New Zealand of Chewings fescue, owing to its great loss in vitality during transit overseas. Tin; causes of this deterioration are now being made the' subject ol special investigation in co-operation with the Bureau of Plant Industry, at Washington. The overseas demand for Chewing's fescue is rapidly diminishing owing to the unsatisfactory germination on arrival in Europe and America. It is hoped that the studies em the loss of vitality in Chewings fescue will have a wide significance, and will be valuable in putting the storage and shipment erf many agricultural seeds on a heller footing. The prices for agricultural se'e;ds have been maintained at an extremely high level during the year. This is especially true, of grass and clover seeds, such as danthemia, brown-top, lotus, and others that are particularly necessary for the; grassing of our poorer lands. In fact, so high has the price of danthonia become that it should be; the policy of all large users of the see;d of this grass to lay down paddocks' specifically for seed-production. Plant-pathology. The Iwo main lilies of work ill plant-pathology have been a study of the dry-rot fungus of swedes {Phoma napo-brassicae Rost.) and fire-blight (Bacillus amylovorus Burr.). Much valuable information on the control of cabbage Phoma was secured in. Wisconsin, where infected seeel Iras been shown to Ire the main method erf spread. From experiments conducted here, however, it appears conclusive thai the swede dry-rot fungus is a soil saprophyte capable of living in the ground for several years. Ne'verthiiess its appearance from time to time' in crops grown on virgin land indicates that the serwing ol' infected see-d is a factor in its dissemination. From Ihe preliminary experimental work carried out it- has been shown that the applie;ation erf large quantities of water-soluble phosphates increases the disease considerably, and that potash manures have a depressing effect on the; development of (he fungus. Much work of a fundamental nature still remains to Ire done before practical methods of control can be' laid down. Fire-blight, which is justly considered one of the mdsl dangerous diseases of pip-fruits, made its appearanoe for the first time in New Zealand during the summer in Ihe Auckland District. Conditions being favourable for lower-infection, the disease spread rapidly, and considerable areas of the Auckland Province have beoome in lee-ted. It is especially bad in the Waikato. Apart from apples and pears, hawthorn has been found to be seriously affected, anel much work has been done to determine whether hold-over- cankers are developeel on this plant. Present indications are that such is the case, and if this proves correct it will make the' control erf fire-blight extremely difficult in districts where hawthorn hedges are largely grown. Just how and when this bacterial disease was imported has not yet been ascertained, but from investigations conducted it appears that the disease is of extremely recent origin here, and the reports that it has been in the Dominion for many years have no foundation. Considerable attention has been given to wheat-diseases, especially with regard to take-all (Ophiobolus graminis Sacc). The control ol wheat-diseases, owing to the altered economic and national position of this crop due ter the lessened production of the, world's liieadstuffs, has become' of considerable moment in New Zealand, and warrants special study being given to the subject.