Ear distortion in barley and other cereals caused by spraying with MCPA and 2, 4-D

Trials made near Cambridge in 1949 and 1950, under ‘mild’ and ‘hard’ spring weather conditions respectively, have confirmed that the findings of Aberg & Denward in Sweden, and of Pedersen, Andersen & Hermansen in Denmark, concerning distortions in barley caused by MCPA and 2,4-D, are also valid under English conditions. 2. Damage to barley caused by the application of MCPA and 2,4-D up to the 2-leaf and early 3-leaf stages may be recognized by the occurrence of many tubular leaves and bowed or trapped ears. As little as 2 lb./acre of 2,4-D, as the amine salt, applied at this stage may also cause severe stunting of theplants with distortion of the roots. 3. Damage to barley by the application of MCPA and 2,4-D at the 3–4-leaf stages may be recognized by the occurrence of tweaked ears. The application of as little as 2 lb./acre of MCPA, as the sodium salt, at these stages may cause tweaking in over 50% of the ears. 2,4-D (as amine) at the same dosage causes more distortion. Although the reduction in yield due to such tweaking may be slight, the grain sample is irregular in size, with a number of naked grains, and malting quality may be reduced.