Effects of microelement-containing pesticides on nutrient concentrations of mango leaves.
Shu Z. H., Sheen T. F., Lin S. L., Lee K. C.
Author Affiliation: Fengshan Tropical Horticultural Experiment Station, TARI, Fengshan, Kaohsiung 83017, Taiwan.
: 553-560
Abstract : Mango cv. Irwin trees (25 years old) were sprayed with various pesticides containing Mn and/or Zn or with solutions containing one or a mixture of all the nutrient elements Cu, Fe, Mn and Zn one week after full bloom. The trees had not received any pesticide applications for at least 2 years previously. Controls were sprayed with water. Leaves were picked for analysis 0, 2, 8, 16 and 240 days after spraying. All treatments increased the foliar content of micronutrients over that of controls and, except for Cu, all elements increased or maintained their levels until the last leaf sampling date. Cu levels peaked at 16 days after spraying but were lower by day 240. The higher nutrient concentrations were not found in the new leaves which emerged after spray treatments, except where sprays of MnSO4, ZnSO4 or a mixture of all micro-nutrients had been applied. It is therefore considered unlikely that the high microelement concentrations accumulated in mango leaves following a single pesticide spray would be translocated to new leaves under normal conditions. However, mango growers in Taiwan commonly spray on a weekly basis during the period of flowering and fruiting.