Anaerobic soil disinfestation with ethanol or sucrose reduces the viability of Meloidogyne javanica and Stromatinia cepivora

Anaerobic soil disinfestation (ASD) is an ecological alternative to chemical soil fumigation. However, little is known about the potential of this technique for the management of Meloidogyne javanica and Stromatinia cepivora. To test the hypothesis that ASD reduces the viability of these two pathogens, we assessed ethanol (5%, v:v) and sucrose (5%, m:v) as carbon sources for ASD, for an incubation period of three weeks. Twenty kilograms of soil naturally infested with M. javanica (82 ± 43 J2 100 cm-3 soil) were placed into a plastic container. Polyester traps, each with 15 S. cepivora sclerotia, were buried at 10 and 20 cm depth per container. ASD with diluted ethanol or sucrose (5% v:v or m:v) was compared to the untreated control (UTC), chemical fumigant metam sodium (MS), and soil saturation with water. In comparison to the UTC, ASD using ethanol reduced the numbers of J2 in soil and the galls in tomato roots by more than 93%, a degree of suppression similar to that achieved when using MS. The viability of sclerotia of S. cepivora was reduced by ASD using ethanol or sucrose from 38.12 to 58.1% compared to the UTC. ASD for three weeks using ethanol or sucrose (5%) reduces the viability of M. javanica and S. cepivora in the microcosm.(AU)

Exogenous application of salicylic acid to control coffee rust

The exogenous application of salicylic acid can induce plant resistance against pathogens. However, little is known about the potential uses of this bioregulator for controlling coffee diseases. In this study, we assessed the effect of applying salicylic acid (SA 150 mg L-1) on the management of coffee rust (Hemileia vastatrix) in a 7-year-old coffee plantation with low crop load (651.6 kg ha-1 in 2017). For comparison, plants were sprayed with protectant fungicide (copper hydroxide CH) and standard fungicides (SF) used by local farmers (boscalid, pyraclostrobin + epoxiconazole, and copper hydroxide). Non-treated plants were included as a negative control. Five monthly applications were performed from November 2016 to March 2017. Rust incidence and severity, defoliation, and growth of plagiotropic branches were evaluated monthly. The activity of catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and total proteins was assessed one day after the first, third, and fifth product applications. Compared to untreated plants, SA reduced the severity and incidence of rust from 36.3 to 54.7%, while CH and SF reduced disease from 31.8 to 54.6% and from 83.8 to 88%, respectively. SA reduced defoliation by 54.1%. SA increased the concentration of CAT, APX, and SOD after the first application. However, this effect was not observed after subsequent applications. Foliar application of SA reduces the severity and incidence of coffee rust and defoliation in plants with a low crop load.(AU)

Exogenous application of salicylic acid to control coffee rust

The exogenous application of salicylic acid can induce plant resistance against pathogens. However, little is known about the potential uses of this bioregulator for controlling coffee diseases. In this study, we assessed the effect of applying salicylic acid (SA – 150 mg L-1) on the management of coffee rust (Hemileia vastatrix) in a 7-year-old coffee plantation with low crop load (651.6 kg ha-1 in 2017). For comparison, plants were sprayed with protectant fungicide (copper hydroxide – CH) and standard fungicides (SF) used by local farmers (boscalid, pyraclostrobin + epoxiconazole, and copper hydroxide). Non-treated plants were included as a negative control. Five monthly applications were performed from November 2016 to March 2017. Rust incidence and severity, defoliation, and growth of plagiotropic branches were evaluated monthly. The activity of catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and total proteins was assessed one day after the first, third, and fifth product applications. Compared to untreated plants, SA reduced the severity and incidence of rust from 36.3 to 54.7%, while CH and SF reduced disease from 31.8 to 54.6% and from 83.8 to 88%, respectively. SA reduced defoliation by 54.1%. SA increased the concentration of CAT, APX, and SOD after the first application. However, this effect was not observed after subsequent applications. Foliar application of SA reduces the severity and incidence of coffee rust and defoliation in plants with a low crop load.

Controle de Meloidogyne javanica com Pochonia chlamydosporia e esterco bovino / Control of Meloidogyne javanica with Pochonia chlamydosporia and cow manure

A aplicação conjunta de agentes de controle biológico e matéria orgânica pode potencializar o controle do nematoide das galhas em hortaliças. Desta forma, o objetivo deste estudo foi avaliar o efeito da aplicação de Pochonia chlamydosporia (Hypocreales: Clavicipitaceae) (PC) e esterco bovino na redução populacional de Meloidogyne javanica (Tylenchida: Heteroderidae) em tomateiro. Os tratamentos foram constituídos da incorporação ao solo de 20g de canjiquinha colonizada pelo fungo (PC), 20g de canjiquinha não-colonizada (CNC), 70g de esterco bovino + 20g de canjiquinha colonizada (EBPC) e apenas 70g de esterco bovino (EB). Ao solo de cada vaso foi adicionado o respectivo tratamento e 5.000 ovos de M. javanica, seguido pelo transplantio das mudas. A incorporação ao solo de EBPC, seguido de EB, aumentou a biomassa da parte aérea e das raízes de tomateiros. A maior redução no número de galhas e de ovos de M. javanica foi observada após a aplicação de EB, seguido por EBPC. Não houve diferença significativa na aplicação apenas do fungo em relação à testemunha considerando a avaliação do número de galhas e de ovos.

Concomitant application of biological control agents and organic amendment can enhance the control of the root-knot nematode on vegetables. Thus, the objective of this study was to evaluate the effect of the application of Pochonia chlamydosporia (Hypocreales: Clavicipitaceae) (PC) and cow manure on the reduction of the Meloidogyne javanica (Tylenchida: Heteroderidae) on tomato. The treatments were: 20 g of milled corn colonized by the fungus (PC), 20 g of non-colonized milled corn (NCMC), 70g of cow manure + 20g of PC-colonized milled corn (CMPC) and 70g of cow manure alone (CM). Into the soil of each pot was added the respective treatment and 5,000 eggs of M. incognita and M. javanica, separately, followed by the transplanting of the seedlings. Soil amendment with CMPC, followed by CM, increased the tomato aboveground and root system biomass. Highest reduction on the number of galls and eggs was observed after soil amendment with CM, followed by CMPC. No significant reduction on the number of galls and eggs was observed by the application of PC.