The Effects of Sub‐lethal Doses of McPa on the Morphology and Yield of Vegetable Crops

Abstract

Summary. The effects of sub‐lethal doses of MCPA‐sodium on the morphology, yield and maturity of French beans, and on the morphology of broad beans, were studied in field and glasshouse experiments. Epinasty in French beans developed at 0.002 lb/ac a.e., but formative effects were not seen at less than 0–1 lb/ac. With doses up to 0.4 lb/ac there was no significant reduction in yield or haulm weight, but at 1.0 lb/ac and above, yield was reduced and some of the plants sprayed at an early stage of growth were killed. There were characteristic modifications of the roots and stems and of those leaves which were at a susceptible stage of development when sprayed. Broad beans were only slightly injured by 0.2 lb/ac but were generally killed by 2.0 lb/ac. Abnormalities were noted in the germination of seed produced by affected plants. Effets de doses sub‐léthales de MCPA sur la morphologic et le rendement des cultures légumières IV. Haricots verts et fèves

The Effects of Sub‐lethal Doses of McPa on the Morphology and Yield of Vegetablecrops

“…Similar effects have been described in beet by Buhl (1958) and in spinach by Middleton & Kendrick (1951); they were also seen in lettuce (Way, 1962) and in carrot and parsnip (Way, 1963a). They were not, however, observed in stem brassicas (Way, 1963), nor in French or broad beans (Way, 1963b), except in rare instances when the leaflets of the trifoliate leaf of French bean were fused together. 'Slipper' leaves, similai-to those in lettuce, were noted in young spinach plants and in both beet and spinach some of the central leaves produced after spraying were reduced in size, stiff and strap-like (Plate 3 b and c).…”