COMBATING RAGWORT

Waikato Times, Volume 121, Issue 20253, 23 July 1937, Page 9

COMBATING RAGWORT

WORK AT RUAKURA

INTENSIVE RESEARCH MADE. RESULT OF INVESTIGATIONS. Another line of attack on ragwort, perhaps the most menacing weed known to the' New Zealand farmer, Is being made by the Department of Agrioulture at the Ruakura State Farm where botanical and ohemlcal research Is being conducted with a systematic thoroughness not hitherto attempted In the Dominion. The men engaged in these investigations have been asked to study every aspeot of the plant and also conduot researches into possible methods of eradication. Up to the present the botanioal side of the investigation is the more advanced, but the chemist has also made a start, and the two scientists working in collaboration are carrying out an Inquiry with minute' thoroughness. The botanical work laid down embraces a study of the life history and habits of the plant, and includes the seedling stage, the duration of the rosette stage, the’ flowering stage, the rooting characteristics, the features and length of the flowering, season, and whether the plant is a biennial or a perennial. The' observations made so far lead to the conclusion that the ragwort plant is an autumn germinating biennial, going through the winter as a rosette, and In the following summer and autumn sending up a flowering spike. The flowering, depends on climatio conditions. Methods of Propagation. The experiments into the methods of propagation reveal that the flower of the ragwort contains 55 seeds, and that a good, strong plant has from 1,000 to 2,000 flowering heads and a germination of from 60 to 80 per cent. The plant has also extremely good root propagation. It sends out a number of fairly fleshy roots which g,o along underneath the pasture for eight inches to two feet, and run underground about two inches below the main pasture roots. The fact that It runs under the main pasture makes It difficult to deal with as it is hard to get at the roots. In the oourse of the researched, the plant has been subject to chipping, debowerlng, cutting down to various heights from two Inohes to a foot, pulling up when in bower, defoliation and severe pasture cultivation. It has been found that ohipping is quite useless because of high vegetative reproduction, and that after a number of plants had been debowere'd every month for four months they sent up a good vigorous fresh crop of flowers again. The plants which had been cut down simply formed again and sent up new shoots from tho crown, which were’ quite vigorous a month afterwards. A month after a number of plants had been defoliated they sent up a good fresh crop of leaves again. Pasture cultivation has had the' same effect as chipping. New plants are produced from regenerated roots. In most cases where the plants have been interfered with in any way before they have seeded, they have' sent up new shoots from the crown which carry the plant through the winter. In that way the plant Is converted Into a perennial. Establishment of Plant. Experiments have' also been started on the actual establishment of the plant in pastures. In one case plots in good cow-grazed pasture have been sown with ragwort seeds e’very month with the object of determining what time or times of the year ragwort is most strongly established in pastures, but this work has not yet proceeded far enough to show noteworthy results. In another instance efforts are being made to find out the effect of different manures, of ordinary grazing and spelling over the winter, and also the effect of increasing the density of sward with brown top. These experiments have not long been under way, and It is yet too early to obtain any definite data. The experiments with sheep and chemicals have only just commenced. In the chemistry work Investigations are being made with sodium chlorate during varying stages of plant growth, and under different conditions of soil moisture for the purposes of finding out the' circumstances in which sodium chlorate is most effective in killing the plant.