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ABSTRACT The objective of this study was to verify the influence of spraying nozzles on the selectivity of herbicides in eucalyptus seedlings. XR 110.02 and TTI 110.02 spraying nozzles were used for the application of the herbicides: control treatment; oxyfluorfen (150 g ha–1) and saflufenacil (98 g ha–1). The experimental arrangement was a 2 × 3 factorial one (two spraying nozzles × 3 herbicides), using a randomized complete block design with four replications. The application was performed 15 days after transplanting the seedlings. Plant height (PH), stem diameter (SD), number of leaves (NL), total dry matter (DM), leaf area (LA), visual phytotoxicity (P), quantum efficiency of photosystem II - Fv/Fm, electron transport rate (ETR) and SPAD (S) index were evaluated. The XR 110.02 and TTI 110.02 nozzles did not change the selectivity of oxyfluorfen and saflufenacil.

ABSTRACT The chemical control of weed is a common practice in silviculture. However, herbicides can potentially damage the main crop and affect its growth. The lack of information about certain species such as Khaya senegalensis make it necessary to know the phytotoxic effects of herbicides. The purpose of this research was to analyze the phytotoxic effects of five herbicides on African mahogany seedlings. The used herbicides were: saflufenacil, amicarbazone, clomazone, isoxaflutole and sulfentrazone, at doses recommended by the Ministry of Agriculture for forest species. Visual, physiological (maximum ETR, SPAD, Yield protocol and FV/FM) and morphological evaluations were performed up to 60 DAA. The symptoms started after 24 hours from the application; saflufenacil and clomazone were the ones that presented more plants with symptoms such as leaf wrinkling and small necrotic spots, but all of them had low phytotoxicity. The physiological evaluations did not present significant differences and the herbicides did not inhibit the growth or the appearance of new leaves. All tested herbicides caused no phytotoxicity to African mahogany seedlings.