Coffee‐leaf extract and phosphites on the curative control of powdery mildew in eucalyptus mini‐stumps

Abstract

The aim of this study was to evaluate the effectiveness of a plant extract obtained from the leaves of coffee plants infected by Hemileia vastatrix (NEFID), different formulations of phosphites and the combination of the extract and phosphites in controlling powdery mildew in eucalyptus mini-stumps, as well as to study the effects on the production of mini-cuttings and their rooting percentage. The experiments were conducted on two eucalyptus hybrids ('urocam' and 'urograndis') in a clonal garden and greenhouse. First, the NEFID plant extract and phosphites of copper, zinc, potassium and potassium/manganese were evaluated to determine their effectiveness in controlling powdery mildew and their toxic effect on the fungus' morphology. Subsequently, we analysed the direct fungitoxicity, curative efficiency and anti-sporulating action of the NEFID extract and various combinations of phosphites with or without the extract, and we also evaluated their effects on shoot production and rooting in eucalyptus mini-cuttings. The NEFID plant extract and phosphites of Cu, Zn and K/Mn were more effective than the fungicide pyraclostrobin + epoxiconazole in the control of powdery mildew. Potassium phosphite was not effective in controlling the pathogen. Among the tested mixtures, the combination of 50% NEFID plant extract and 50% copper phosphite was the most effective because it exhibited direct toxicity on powdery mildew, a high curative efficiency, anti-sporulating action and no adverse effects on the production of shoots or rooting in eucalyptus mini-cuttings.

Phosphorus, nitrogen and potassium nutrition on Calonectria leaf blight in eucalypt plants

“…Average measurement 1 Average measurement 2 * * * * E. marginata (Jackson, Burgess, Colquhoun, & Hardy, 2000;Shearer, Fairman, & Grant, 2006); and controlling Oidium eucalypti in eucalypt mini-stumps (Silva, Resende, Souza, Pôssa, & Silva Júnior, 2016;Silva et al, 2013). According to Perrenoud (1990), the results of the use of P in controlling disease are contradictory.…”

Manganese Phosphite in Coffee Defence against Hemileia vastatrix, the Coffee Rust Fungus: Biochemical and Molecular Analyses

“…Phosphites are inorganic salts of phosphorous acid (H 3 PO 3 ) formulated with potassium, manganese, copper or zinc. In the United States, phosphites are registered for the control of oomycetes (King et al 2010) while in Brazil they are considered foliar fertilizers and reduce disease severity in various crops such as onion (Wordell Filho and Stadnik 2006), papaya (Dianese et al 2008(Dianese et al , 2009, grapevine (Pereira et al 2010, mango (Araujo et al 2015), eucalyptus (Silva et al 2013) and coffee (Nojosa et al 2009;Dalio et al 2012;Costa et al 2014). In the United States, phosphites are registered for the control of oomycetes (King et al 2010) while in Brazil they are considered foliar fertilizers and reduce disease severity in various crops such as onion (Wordell Filho and Stadnik 2006), papaya (Dianese et al 2008(Dianese et al , 2009, grapevine (Pereira et al 2010, mango (Araujo et al 2015), eucalyptus (Silva et al 2013) and coffee (Nojosa et al 2009;Dalio et al 2012;Costa et al 2014).…”

“…These inorganic compounds can influence pH and redox homeostasis, hormone signalling and enzymes involved in stress response (Du Jardin 2015). In the United States, phosphites are registered for the control of oomycetes (King et al 2010) while in Brazil they are considered foliar fertilizers and reduce disease severity in various crops such as onion (Wordell Filho and Stadnik 2006), papaya (Dianese et al 2008(Dianese et al , 2009), grapevine (Pereira et al 2010, mango (Araujo et al 2015), eucalyptus (Silva et al 2013) and coffee (Nojosa et al 2009;Dalio et al 2012;Costa et al 2014).…”

Plant extract, zinc phosphite and zinc sulphate in the control of powdery mildew in the eucalyptus

“…Já Bizi et al (2008) GRANT, 1991;McDONALD;PLAXTON, 2001;SILVA et al, 2011). Embora não tenha sido evidenciado que as plantas se beneficiem do fosfito como fonte de fósforo, alguns pesquisadores defendem a ideia de que os elementos que acompanham essa molécula nos produtos à base de fosfitos, como por exemplo, zinco (fosfito de zinco) poderia atuar na nutrição, fornecendo esse elemento à planta (DALIO et al, 2012), agindo diretamente sobre o patógeno (SILVA et al, 2013) e o fato de que os micronutrientes funcionam como cofatores das enzimas envolvidas na síntese de compostos fenólicos (SILVA et al, 2008). No entanto, Bizi et al (2008) observaram que o fosfito de potássio a 0,6 mL L -1 e o fosfito de cobre a 0,2 mL L -1 não foram eficientes no controle do oídio em eucalipto.…”

“…Tendo em vista tais problemas e com base na literatura, é evidente que os extratos de plantas e os sais inorgânicos emergem como uma alternativa promissora aos defensivos convencionais (BARGUIL et al, 2005;DALIO et al, 2012;MEDEIROS et al, 2009;SANTOS et al, 2007;SILVA et al, 2013;2014). Outro fator importante dos sais inorgânicos é que possuem perfil de segurança favorável para os seres humanos e ao ambiente, bem como baixa toxicidade em mamíferos, além do seu baixo custo (OLIVIER; MACNEIL; LORIA, 1999;REUVENI, 1995).…”