Nebenwirkungen Bei Der Nematodenbekämp-Fung Mit Shell D-d uNd Verwandten Mitteln

Abstract

The secondary action of Shell D-D and similar compounds based on Dichloropropen, over and above their nematicidal properties, has frequently been referred to in the literature, and takes the form of growth stimulation in crops cultivated after soil treatment with these compounds. Stimulation was investigated in an instance in which increased growth occurred in fodder beet in 1957. The field was treated with DD in 1955 to control potato-root eelworm, potatoes were grown in 1956, and fodder beet in 1957. Species of nematodes injurious to sugar beet were not found in the treated or untreated plots. Leaves from DD treated plots compared with those from untreated plots possessed a higher water content, lower osmotic pressure in the sap, a lower water deficit, greater succulence, a smaller surface area, and a raised ash content. In wilting experiments the fall in water content, and the rise in osmotic pressure and water deficit were slower than in plants from untreated soil. Recovery from wilting was quicker and more marked. Under the local weather and other conditions, the difference in wilting properties of the plants from treated and untreated soil would account for the growth differences. Three months after injection, the soil treated with DD in October 1957 showed a higher electrolyte, water and ammonium nitrogen content, and reduced evaporating power. Since the qualitative changes in plants and soil brought about by DD correspond to the specific functions of Cl-ions, it is very probable that the secondary action of this nematicide is due to its chlorine content.