Foliar-Applied Melatonin Mitigates Carryover Injury Caused by Premix Herbicide Lumax®537.5SE in Potato

Carryover injury caused by premix herbicide Lumax (R) 537.5SE has not been studied. This study documents this event and aims to support or reject the following hypothesis under field conditions: a crop treated with melatonin, a plant hormone, can tolerate herbicide carryover-induced stress. A split-plot design was arranged in a randomized complete block design (RCBD). Main plots were 0, 4, and 6 L ha(-1) Lumax (R) 537.5SE applied 11 months before planting. Subplots were non-treated control and melatonin applied at 1 mM in the manners of seed tuber application, single foliar application, single foliar + seed tuber application, double foliar application, and double foliar + seed tuber application. Without Lumax (R) 537.5SE, single foliar application of melatonin increased the yields of marketable No. 1 (20%), unmarketable (34%), and total (15%) tubers compared to control. The double foliar application of melatonin caused a further increase in the yields. The carryover of Lumax (R) 537.5SE injured potato by reducing and cracking its tubers in a dose-dependent manner. Without Lumax (R) 537.5SE, no cracked tuber was harvested, while with 4 and 6 L ha(-1), 0.46 and 0.63 kg m(-2) tubers were cracked, respectively. The seed tuber application of melatonin did not affect improving potato and mitigating it against Lumax (R) 537.5SE carryover. Other melatonin treatments reduced cracks in the tubers, improving the yields. Quality and quantity loss of tubers caused by Lumax (R) 537.5SE carryover could be mitigated by foliar-applying melatonin twice.

Automated summary

This study investigates the effects of carryover injury caused by Lumax(R)537.5SE herbicide on potatoes and finds that applying melatonin can increase potato yield and mitigate the carryover injury.