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Brassica Diseases. (a) Dry-rot. —In the past four seasons seed-treatments have proved satisfactory in the laboratory, yet apparently failed when applied on a field scale. The reasons for this have been the subject of a considerable investigation during the past twelve months. It, was thought that possibly the technique for testing the presence of the dry-rot organism in the seed was faulty. Consequently three different tests were utilized —the standard method, which consists of sowing seeds in lots of 100 on culture media in petri dishes ; the " Copenhagen " germinator method, which consists of sowing seeds in lots of 25 on sterile blotting-paper covered by glass cloches and kept moist in this germinator ; sowing seeds in lots of 100, in sterilized soil, kept in sterilized tins in the glasshouse. In testing the standard method, 500,000 seeds were tested ; in the soil method, 60,000 seeds were tested ; and in Copenhagen germinators, 20,000 seeds were tested. All were from one line of seed, known to carry the dry-rot organism. Results showed that the standard method was much more reliable than either of the other two. A second point under investigation was the possible spread in the fields by insects. A fields survey showed that certain insects were invariably associated with infected roots. These have been isolated and are at present being tested with a view to determining whether any insect is a carrier, and, if so, the methods by which the disease is conveyed under field conditions. A third point under investigation was to determine the manner in which seed became infected in the field. Swede roots were grown to seed under controlled conditions (in insect-proof cages) and inoculated at various times. As a result a quantity of heavily infected seed was obtained, the method demonstrating that if the seed-pods became infected, infected seed results. Further work on seed-disinfection on a field scale has been undertaken. A modified form of the treatment previously recommended was developed and tested by all three methods outlined above. As all tests showed the seed to be dry-iot free, 4201b. were treated and distributed to experimental areas throughout the Dominion. As this experimental series is not yet completed, results are not available. The modified treatment used was to soak seed for twelve hours in water, followed by a dip of five minutes in 0-25 per cent, semesan at 115° F. Attempts at producing small lines of dry-rot-free seed are being undertaken on Hautu Prison Farm, Tokaanu. Seed of a few selected commercial lines have been treated and sown on land never before in swedes and miles away from other root crops in that locality. (b) Club-root. —An intensive series of investigations covering this disease has been carried out during the year, one officer occupying his whole time with this work. Preliminary work of a technical nature was required to work out a method for testing the presence of the disease in the soil ; effects of soil conditions, temperature, moisture, spore-load, time of infection, &c. Following this the following major points were investigated : — Firstly, the possibility of there being definite biological strains had to be determined, to know whether one type of brassica (as rape) could or could not be grown on land previously under another type of brassica (as swede). No significant results were obtained, indicating that defined biological races do not exist in the New Zealand form of this disease. Secondly, the host-range of the organism had to be ascertained in order to determine whether brassica weeds could carry the disease over in grassland for an indefinite period. Seeds of thirtythree species of weeds were collected and sown in specially prepared boxes of sterilized soil, to which viable spores of the club-root organism had been added. Infection was obtained on nine species, only one of which, Capsella bursa-pastoris (shepherd's purse), had any economic significance in that it is an abundant weed in cultivated areas. This work is being repeated on a larger scaleThirdly, an intensive series of investigations were conducted to determine whether the disease was carried with the. seed. This work has as yet been negative; but this is to be expected, since preliminary investigations showed that infections were directly correlated with spore-load —in other words, that infection could be obtained artificially only when numerous spores were present in the inoculum. Fourthly, a series of experiments has been conducted with a view to determining whether any varieties of swedes or turnips are markedly resistant to club-root. Of all those tried, Herning swede showed distinct promise, in several of the plots remaining quite free from the disease. Work now in hand is concerned with determining how long the organism may remain in a viable condition in the soil, and whether any manurial culture practice or rotation will affect this period. (3) Heart-rot of Mangolds. An investigation into the cause and possible control of this disease is now being conducted. (4) Linseed-rust. A small nucleus line of " J.W.S." linseed has been produced free from rust (Melampsora Lini). This is now available for bulking. (5) Sclerotial Diseases. One of the most serious groups of parasitic fungi are those sclerotial diseases attacking tomatoes, lupins, potatoes, sunflowers, vegetables, flowers, artichokes, &c. Consequently, one of the major investigations now being undertaken covers these organisms. (6) Collar-rot of Peas. An intensive series of seed-disinfectant experiments has been undertaken wth a view to combating this serious disease, but with different results. It has been found that experiments in control along these lines have been deleteriously affected by secondary infections coming from outside sources. Consequently, until this disease has been more fully studied under laboratory conditions, control experiments have been discontinued.