Combined use of foliar zinc fertilisation, thiamethoxam and propiconazole does not reduce their effectiveness for enriching zinc in wheat grains and controlling insects and disease

Abstract

Agronomic biofortification is possible through foliar zinc fertilisation around the earing and early milk stage of wheat. Farmers can be encouraged to apply foliar zinc fertilisation if there is yield enhancement or if it is compatible with other pesticides which are used during these stages to control aphid and stripe rust. To investigate the effectiveness of tank-mix applications of fertiliser and pesticide for enriching grain zinc and controlling the spread of aphid and stripe rust, studies were conducted at Punjab Agricultural Univeristy, Ludhiana, India for 4 years (2017–18 to 2020–21). We tested tank-mixing of zinc (0.5% ZnSO4.7H2O) + thiamethoxam 25 WG (50 g/ha), zinc + propiconazole (500 mL/ha) and zinc + thiamethoxam + propiconazole with one foliar application at the milk stage and two foliar applications at the flag leaf and milk stages. We did not find any adverse effect of tank-mix application of zinc sulfate, thiamethoxam and propiconazole on zinc enrichment in grains, nor in aphid and stripe rust control. The grain zinc enhancement was 99.8–114.9, 100.2–112.1 and 98.0–115.5% with application of foliar Zn, foliar Zn + thiamethoxam and foliar Zn + thiamethoxam and propiconazole respectively. We also found 5.74% increased grain yield with foliar Zn + thiamethoxam and 7.24% increased grain yield in foliar Zn + thiamethoxam + propiconazole. Better net returns in combining Zn + thiamethoxam + propiconazole were also recorded. The results advocate for the tank-mix application of Zinc + thiamethoxam + propiconazole for pest management and Zn biofortification.