Action of trifluralin on mycorrhization and growth of peanut (Arachis hypogaea) plants

During their initial developmental stages, peanut (Arachis hypogea) plants suffer weed competition with more intensity, leading to severe losses. A very efficient way to solve this problem is using trifluralin; however, this herbicide can harm mycorrhization, a beneficial association formed by the host plant's fungi and roots. This work aimed to evaluate the effect of trifluralin and of two species of mycorrhizal fungi (Gigaspora margarita and Acaulospora scrubiculata) on mycorrhyzation and the initial growth of peanut plants. The experiment was carried out under greenhouse conditions at the Agricultural, Environmental and Biological Center of the Universidade Federal do Reconcavo Bahiano, in Cruz das Almas-BA, using the peanut cultivar Vagem Lisa. The treatments tested involved application (W/H) or not (WO/H) of the herbicide and individual inoculation of two mycorrhizal fungi, Gigaspora margarita (F1) and Acaulospora scrubiculata (F2), as follows: WO/H + F1, WO/H + F2, W/H + F1, W/H + F2, W/H WO/F (without the fungus) and WO/H WO/F. The experiment was arranged in a complete randomized block design in a factorial scheme (2 x 2) + 2, with four replicates. Results showed that mycorrhizal colonization for Gigaspora margarita was 63%, and 44%, when the herbicide was applied; Acaulospora scrubiculata presented low colonization index (5.75% and 1%, without and with herbicide application, respectively);mycorrhizal efficiency was superior in the association with G. margarita; mycorrhizal dependence increased in the presence of the herbicide for both the fungi species inoculated; plant height, root volume and root, with upper plant dry mass and plant dry mass being superior in comparison to the other treatments. It was concluded that the herbicide trifluralin harms mycorrhization and the initial growth of peanut plants. The fungus species Gigaspora margarita promoted the initial growth of peanut plants; however, the species Acaulospora scrubiculata was not efficient in promoting this type of growth.

herbicide; mycorrhiza; inoculation