Effects of Certain Growth-Regulating Compounds on Irish Potatoes

Abstract

1. The substance 2,4,5-trichlorophenoxyacetic acid and other compounds with the 2,4,5-trichlorophenoxy- configuration have been shown to have a decided herbicidal action on the Irish potato, while other phenoxyacetic acid derivatives applied in sprays at comparable rates produce markedly less and different effects. 2 The compound 2,4,5-trichlorophenoxyacetic acid, when applied to vegetative portions of Irish potato plants in aqueous or oil sprays, or to the soil, causes pronounced stunting and distortion of vegetative growth, swelling of the pulvini, and marked reduction in yield and quality of tubers. 3. The chlorinated 5 position of substituted phenoxyacetic acids does not appear to have any significance as far as the phytocidal action of such compounds on the potato is concerned, whereas the 2,4,5-trichloro-configuration appears to be significant. 4. The use of substituted phenoxyacetic acids, such as 2-methyl-4-chlorophenoxyacetic acid and 2,4-dichlorophenoxyacetic acid, may be of value for the selective control of weeds in potato fields. Further testing of such compounds for herbicidal use against weeds in potato fields is suggested.