Ramularia leaf spot and boll rot are affected differently by organic and inorganic nitrogen fertilization in cotton plants

Abstract

Interaction among nitrogen fertilization using bovine manure, poultry manure, Jatropha curcas seed cake and urea, and the diseases Ramularia leaf spot (RLS) and Boll rot (BR), caused by Ramulariopsis pseudoglycines and Diplodia gossypina, respectively, in cotton plants (Gossypium hirsutum L.), was studied under field conditions. Intensity (incidence and severity in percentage) of RLS and incidence (%) of BR were evaluated over time, starting in reproductive stage B1 (first visible flower bud). A randomized complete block design with a 4x4 factorial arrangement was used (fertilizers x doses), totaling 16 treatments with four replications. Disease progress was analyzed with the nonlinear Logistic and Gompertz models, obtaining the epidemiological parameters amount of initial disease (Y0) and progress rate (r). Plants fertilized with 50 kg N ha-1, presented an incidence twice greater than those obtained with other fertilizers. The Logistic model better fits RLS, but no model could represent BR. Only the epidemiological parameters of RLS were affected differently in this experiment compared to BR disease. The possible role of organic and inorganic nitrogen fertilization in the RLS and BR management is discussed.

Cercospora leaf spot management with nitrogenous fertilizers in cotton is dependent on the disease amount in the plant canopies

“…It is conceivable that the higher levels of Ca in poultry manure, being twice as abundant as in other fer-tilizers, might contribute uniquely to the health of cotton plants. This suggests that the incidence of diseases in cotton plants may vary significantly with the type of fertilizer used (Palma-Zambrano et al, 2022). Upon analyzing Factor B (dosage), the severity of Cercospora leaf spot in the lower canopy of cotton plants decreased by 29% with applications of 100 to 200 kg N ha -1 , in comparison to lower doses.…”

“…However, the use of inorganic or synthetic fertilizers can be detrimental to an agroecosystem because it may lead to air and groundwater pollution, soil acidification, eutrophication, and a reduction of biodiversity, which includes microorganisms (Scudlark et al, 2005;Zheng et al, 2018). As an alternative to this approach in nutritional management for cotton cultivation, more environmentally friendly practices can be adopted, such as the use of organic nitrogen sources (Palma-Zambrano et al, 2022). Nitrogen fertilizer, regardless of its source (NH3 or NH4 + ), can not only positively affect root condition, plant growth, boll quality, and fiber production in cotton crops (Chen et al, 2019; but also suppress various phytopathogens, potentially influencing their interaction with the plant (Mur et al, 2017;Palma-Zambrano et al, 2022).…”

“…As an alternative to this approach in nutritional management for cotton cultivation, more environmentally friendly practices can be adopted, such as the use of organic nitrogen sources (Palma-Zambrano et al, 2022). Nitrogen fertilizer, regardless of its source (NH3 or NH4 + ), can not only positively affect root condition, plant growth, boll quality, and fiber production in cotton crops (Chen et al, 2019; but also suppress various phytopathogens, potentially influencing their interaction with the plant (Mur et al, 2017;Palma-Zambrano et al, 2022). In crops such as oilseed rape (Brassica napus L.), increased N availability may lead to the emission of acetic acid (a volatile antifungal component), which can potentially reduce the levels of Alternaria leaf spot [Alternaria brassicae (Berk.)…”

“…in the leaf area (Veromann et al, 2013). In cotton, higher nitrogen doses can enhance root growth (especially in the upper soil layers) and boost physiological and biochemical processes in leaves (Chen et al, 2019) and may also diminish the intensity or epidemiological components of diseases such as boll rot (Diplodia gossypina Cooke) and Ramularia leaf spot (Ramulariopsis pseudoglycines Videira, Crous & U. Braun) (Palma-Zambrano et al, 2022). Cotton crops in Ecuador may be affected by diseases such as damping-off (Rhizoctonia solani J.G.…”

“…Cotton crops in Ecuador may be affected by diseases such as damping-off (Rhizoctonia solani J.G. Kühn), anthracnose (Colletotrichum gossypii Southw), boll rot, and ramularia leaf spot (Sión et al, 1992;Palma-Zambrano et al, 2022). Diseases like Ramularia leaf spot can negatively affect cotton plants' leaf area and fiber yield (Ascari et al, 2016).…”