Fosfito No Controle Da Antracnose E Qualidade Pós-Colheita De Goiaba Em Cultivo Convencional E Orgânico

Abstract

Este estudo avaliou o efeito de fosfitos (Fos) sobre a ocorrência natural e artificial da antracnose (Colletotrichum gloeosporioides (Penz) Penz and Sacc) na pós-colheita da goiaba (Psidium guajava). A qualidade física e química indicadas pela perda de massa fresca (PMF), pH, sólidos solúveis (SS), acidez titulável (AT) e maturação da goiaba ‘Pedro Sato’ oriunda de produção convencional (Co) e orgânica (Or), com ou sem inoculação pós-colheita do patógeno foram avaliadas. Os tratamentos {Fos [Ca (30% P2O5 + 7% Ca / ‘Phytogard Ca’ 3 mL/L); Zn (40% P2O5 + 10% Zn / ‘Phytogard Zn’ 2,5 mL/L); Mg (40% P2O5 + 6% Mg / ‘Fitofós Mg’ 1,5 mL/L); K (40% P2O5 + 20% K2O / ‘Fitofós K plus’ 1,5 mL/L)]} e o fungicida (Carbendazim - ‘Derosal’ 1 mL/L) foram aplicados aos frutos. O tratamento testemunha foi com água esterilizada. O diâmetro das lesões (DL) , o grau de maturação e o número de lesões naturais (NL) bem como as análises físiicas e químicas dos frutos foram avaliados. Os resultados mostraram que o DL em frutos de Co foi menor com a aplicação dos Fos. Em fruto de Or, a redução do DL se deu com a aplicação do Fos Zn e K. O NL em frutos de Co foi menor com a aplicação dos Fos Mg, Zn e K. O Fos K reduziu o DL em frutos de Co e Or em todas as doses testadas. O Fos Zn e o Carbendazim retardaram a maturação de frutos.

Effect of Conventional and Alternative Products on Postharvest Disease Control in Avocados

“…Fruits that received water treatments with potassium phosphite, Soil-Set ® , chlorine dioxide, thyme essential oil, sodium bicarbonate, lemon grass essential oil and thiabendazole had lower disease incidence (53.4-66.5%), relative to control treatment (77.8%), which did not differ from treatments with Agro-Mos ® and acibenzolar-Smethyl (Table 2). Greater fruit conservation, due to rot control and/or delayed ripening, was already reported for most of the studied products applied in the postharvest, such as thyme essential oil (SELLAMUTHU et al, 2013), chlorine dioxide and thiabendazole in avocado (FISCHER et al, 2011), potassium phosphite in guava (FERRAZ et al, 2016), sodium bicarbonate in papaya (HASAN et al, 2012), and lemon grass essential oil in passion fruit (MOURA et al, 2012) and papaya (CARNELOSSI et al, 2009). However, the efficiency of postharvest disease control with acibenzolar-S-methyl and Agro-Mos ® in banana (PESSOA, 2009) and acibenzolar-S-methyl in papaya (DANTAS et al, 2004) was not confirmed in the present study in avocados.…”

“…'Hass' avocados, harvested from a commercial orchard located in Bauru, SP, were standardized as to the absence of defects, washed under tap water with a foam sponge and neutral detergent, and immersed for 60 seconds (time taken by the fruit to pass through the packinghouse ferry) in a suspension containing the following products (g L (S 3.8%, Cu 2.0%, Fe 1.6%, Mn 0.8%, Zn 3.2%, organic carbon 1.7% and amino acids as complexing agents 5.0%) (1.5), e) chlorine dioxide (0.2 active chlorine) (FISCHER et al, 2011), f) potassium phosphite (40% P 2 O 5 and 20% K 2 O) (1.5) (FERRAZ et al, 2016), g) sodium bicarbonate (20) (HASAN et al, 2012), and h) thiabendazole (1.94) (BRASIL, 2017). As phytotoxicity occurs when fruits are immersed for 60 seconds, essential oils of lemon grass (Cymbopogon citratus) (1) (MOURA et al, 2012) and white thyme (Thymus vulgares) (1) (SELLAMUTHU et al, 2013) were sprayed on the fruits until runoff.…”

“…Nevertheless, due to increasing restrictions on the use of fungicides in the postharvest, some countries like France do not allow postharvest treatment with prochloraz (SCHAFFER et al, 2013). Alternative methods that are feasible to the small farmer and that were already tested in the postharvest showing certain efficiency for fruiting plants include application of phosphites (FERRAZ et al, 2016), chlorine (FISCHER et al, 2011), acibenzolar-S-methyl (DANTAS et al, 2004PESSOA, 2009), Agro-Mos ® (phosphorylated mannanoligosaccharide-based product) (DANTAS et al, 2004;PESSOA, 2009), sodium bicarbonate (HASAN et al, 2012) and essential oils (MOURA et al, 2012;SELLAMUTHU et al, 2013). Association between essential oils and wax-based coating was effective for pathogen control in avocados (REGNIER et al, 2010).…”

Anthracnose control of ‘Prata-Ana’ banana with pre-harvest phosphite application

“…The application of FK provided low efficiency in the anthracnose control, and results obtained were similar to those of control. The low efficiency of potassium phosphite was also observed by Ferraz et al (2016). Potassium phosphite showed low anthracnose control in guava when compared with Zn and Mg phosphites.…”

“…Tukey's 5% test was used for treatments and Student's t test was used for different application frequencies. In the data analysis processing, the SISVAR software was used (FERREIRA, 2008).…”