ATTACK ON RAGWORT.

Manawatu Standard, Volume LVII, Issue 201, 26 July 1937, Page 5

ATTACK ON RAGWORT.

NEW LINE DEVELOPED. Another line of attack on ragwort, perhaps the most menacing weed known to the New Zealand farmer, is -being made bv the Department of Agriculture at the Ruakura State Farm at Hamilton, where botanical and chemical 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 aspect ot the plant, and also conduct researches . o possible methods of eradication. Up to the present the botanical side of the investigation is the more advanced, btu the chemist has also made a start, and the two sciontists wo'Jving in collaboration arc carrying out. an enquiry with minute thoroughness. The botanical work laid down a study of the life history and habits ot the plant, and includes the seedling stage, tlie duration of the rosette stage, the flowering slage the. roc-ting 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 1o 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 flowcimg depends oil climatic conditions. The experiments into the methods or propagation reveal that, the flower of tho ragwort centains 55 seeds, and that a good, strong plant has from 1000 to 2000 flowering heads and a germination of from ot) to 80 per cent. The plant has also extremely good root propagation. It sends out a number of fairly fleshy roots whir* go along underneath the pasture for eight inches to two Sect., and run underground about two inches, below the mam pasture roots. The fact that it runs under tho main nature makes it difficult to deal with as it is hard to get at the roots. Tn -ho course of the ruenrches, the plant has been subject to chipping, deflowering, cutting down to various heights from two inches to a foot, pulling up when in flower, defoliation, and severe pasture cultivation R has been found tha.t chipping is quite useless because of high vegetative reproduction, and that after a number of plants had been deflowered every month for four months they sent up a good vigorous fresh crop of flowers again. The plants which had been cut down simplv formed again and sent up now shoots from the crown, which were quite vigorous a month 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 arc produced from regenerated roots. Tn most cases where tho plants have been interfered with in any way before they h"ve seeded, they have sent, up new shoots from the crown which cnrrv the plant through tho winter. In that way the plant is converted into a perennial. ESTABLISHMENT TN PASTURES. Experiments bnve also been started on Ibe actual establishment- of the plant in pastures. In one case plots in good cowgrazed pasture have been sown with ragwort seeds every month with the object of determining what time or times ef the vear ragwort is most strongly established in pasture, but Ibis work has not, yet, proceeded far enough to show noteworthy resuits. T . In another instance efforts arc being made to find out the effect of different mnn. in-cs of ordinary grazing and spelling over the winter, and also the effect of mcrcasthe density of sward with brown lop. These experiments have not long been under way. arid it is yet too early to obtain any definite data. The experiments with sheen and chemicals have only just commenced. In tbe chemistry work investigations are being made with sodium chlorate during varving stages of plant, growth, and under different conditions of soil moisture for the purpose of finding out the circumstances in which sodium chlorate is most effective in killing the plant.