Tolerance of two pitaya species to post-emergence herbicides

Abstract

Pitaya production has been expanding in several regions of Brazil despite the lack of technical information on plant management. To obtain good crop productivity, weed control is essential; however, the use of herbicides can cause phytotoxicity and reduce plant growth and production. Thus, the present work aimed to evaluate the tolerance of red (Selenicereus polyrhizus) and white (S. undatus) pitaya seedlings to different herbicides applied after emergence. Two experiments were installed, one with red pitaya and the another with white pitaya, on August 15, 2020 in the Fruit Production Sector of the Federal University of Lavras. Experiments were arranged in a randomized block design, with four and three replicates, respectively, eight treatments and three plants per plot in both experiments. Treatments consisted of control, fomesafen, ammonium glufosinate, glyphosate, clethodim, carfentrazone-ethyl, imazethapyr and chlorimuron. Visual phytotoxicity symptoms were evaluated at 7, 14, 21 and 28 days after herbicide application. At 30 and 60 days after application, percentage of necrosis, cladode length and number of new shoots were evaluated. Herbicide fomesafen caused greater damage to red pitaya seedlings and fomesafen and glyphosate caused greater damage to white pitaya seedlings. For both pitaya species, herbicide clethodim can be an alternative for controlling narrow-leaf weeds without causing visual damage to the growth and development of pitaya plants.