Intoxication of newly implanted coffee plants by simulated drift of the dicamba herbicide

Abstract

After the release of soybean cultivars resistant to the herbicide dicamba, this product should be used more frequently in weed management programs, which may increase the risk of drift to neighboring crops, since the molecules are volatile and might cause damage in non-target plants. This work was developed to evaluate the effects of sub-doses of the herbicide dicamba on young coffee plants, simulating a drift situation. The experiment was carried out in a greenhouse, with a randomized block design of eight treatments and five replications. Each plot consisted of a 4 L pot, filled with sieved clayey soil and tanned manure (3:1 v/v), with a seedling of Catuaí IAC 144 coffee. The treatments used were: 0 (control), 0.0001, 0.001, 0.01, 0.1, 1.0, 10.0, and 100.0 g ha−1 of dicamba. Plant's percentual phytotoxicity was evaluated up to 49 days after application (DAA), SPAD index (14, 28, and 42 DAA), and dry matter biomass, at 49 DAA. In all evaluations, no differences were observed regarding phytotoxicity for dicamba sub-doses of up to 0.01 g ha−1. The highest doses of dicamba caused visual injuries of up to 31%. At 49 DAA, there were no differences regarding dry matter biomass. Leaf symptoms caused by the herbicide were observed, such as curling, wrinkling, and epinasty. No plant death was observed. Compared to other crops, coffee might be considered more tolerant to sub-doses of dicamba, with adequate recovery capacity for reduced doses of this herbicide.