Simulated drift of 2,4-D and dicamba in pecan

• Published in: Ciência florestal Vol. 34; no. 1; p. 1
• Main Authors: Rubert, Jaíne, Tarouco, Camila Peligrinotti, Wesz, Alessandra Minuzzi, Bortolin, Eduardo Streck, dos Reis, Cleisson Batista Vaz, Dornelles, Sylvio Henrique Bidel, da Rosa Ulguim, AndrÃ
• Format: Journal Article
• Language: English
• Published: Universidade Federal de Santa Maria 01.01.2024
• ISSN: 1980-5098; 1980-5098
• DOI: 10.5902/1980509869073

The cultivation of pecan (Carya illinoinensis K. Koch) and olive trees (Olea europaea L.) near pasture and grain cultivation areas in southern Brazil has caused herbicide drift problems. Therefore, the objective of this study was to evaluate the phytotoxic effects of herbicides 2,4-D and dicamba on the growth of pecan and olive tree seedlings. A total of 8 underdoses were used, as follows: 0, 1.56, 3.125, 6.25, 12.0, 25.0, 50.0, and 100% of the recommended doses of herbicides 2,4-D (670 g a.e [ha.sup.-1]) and dicamba (720 g a.e [ha.sup.-1]) for burndown. The applications were carried out in 80 cm-high seedlings with the aid of a [CO.sub.2] pressurized sprayer with a spray solution volume of 150 L. [ha.sup.-1]. The analyzed variables were phytotoxicity at 7, 14, 21, 30 and 60 days after spray (DAA) and plant height and stem diameter at 30 and 60 DAA. The drift of hormonal herbicides caused damage to the growth of pecan and olive trees, decreasing their stem diameter and height, with the herbicide dicamba showing the greatest damage. In addition, doses above 12.5% of both herbicides resulted in phytotoxicity levels greater than 60%, and doses of 50 and 100% were responsible for leaf senescence. Keywords: Underdoses; Herbicides; Phytotoxicity O cultivo de nogueira-pecã (Carya illinoinensis K. Koch) e oliveira (Olea europaea L.) no Sul do Brasil próximo a áreas de pastagens e de cultivo de grãos tem registrado problemas de deriva de herbicidas. Diante disso, o objetivo do trabalho foi avaliar os efeitos fitotóxicos dos herbicidas 2,4-D e dicamba sob 0 crescimento de mudas de nogueira-pecã e oliveira. Para isso, utilizaram-se 8 subdoses, sendo elas 0; 1,56; 3,125; 6,25; 12,0; 25,0%; 50,0; e 100% das doses recomendadas para dessecacão dos herbicidas 2,4-D (670 g e.a [ha.sup.-1]) e dicamba {720 g i.a [ha.sup.-1]). As aplicacoes foram realizadas em mudas com 80 cm de altura com auxílio de um pulverizador costal pressurizado a [CO.sub.2] com volume de calda de 150 L [ha.sup.-1]. As variáveis analisadas foram a fitotoxicidade aos 7, 14, 21, 30 e 60 dias após a aplicacão (DAA), estatura de plantas e diâmetro de caule aos 30 e 60 DAA. A deriva de herbicidas hormonais causou danos ao crescimento das plantas de nogueira e oliveira, diminuindo o diâmetro de caule e a estatura das mesmas, sendo o herbicida dicamba o responsável pelos maiores danos. Além disso, doses acima de 12,5% de ambos os herbicidas resultaram em fitotoxicidade superior a 60%, sendo as doses de 50 e 100% responsáveis pela senescência de folhas. Palavras-chave: Subdoses; Herbicidas; Fitotoxicidade