Seed disinfection: III. Experiments on the germination of peas. Seed protection by the use of disinfectant dusts containing mercury

In a previous paper(1) reference was made to the subject of seed disinfection, in particular to an investigation on disinfectant dusts containing mercury. It was shown that by the use of certain of these dusts the common seed-borne diseases of cereals (excluding the loose smuts of barley and wheat) could be controlled. The present observations record further work, chiefly greenhouse and field studies, that has been done on green peas. This crop would appear to be of increasing economic importance, since in the past ten years the acreage devoted to it has increased by approximately 49 per cent. Its successful cultivation is often much influenced by climatic and soil conditions, particularly during the first few weeks after sowing. If adverse weather conditions follow, poor germination may result although the seed sown may have been viable and not necessarily diseased. Failures of such a type are usually associated with the rotting of the ungerminated seed in the soil, but from the same bulks, samples sown under more favourable conditions may germinate well and produce a satisfactory crop. Ogilvie (2,3,4) finds that in the Western Advisory province Ascochyta Pisi and Mycosphaerella pinodes are two causes of the early failure of pea plants, and that “pea sickness” is associated with a strain of the eelworm Heterodera schachtii and with foot-rot caused by various species of Fusarium. Premature dying-off of the plants is accompanied sometimes with Heterodera schachtii and foot-rot and sometimes with foot-rot alone.