Outbreak of stem bleeding in coconuts caused by Thielaviopsis paradoxa in Sergipe, Brazil

Abstract

In February of 2004, at "Platô de Neópolis", Sergipe, Brazil, about 50 coconut plants were found bearing symptoms of a disease not yet recorded in Brazil. The trunk of diseased plants exhibited a reddish-brown or rust��colored liquid bleeding from scars. Inside the stem, the tissues under the lesions were rotting and turned brownish-yellow to black. Diseased palms had reduced growth and three to four months after the first symptoms were noticed the affected plants died. A fungus was isolated from diseased tissues and identified as Thielaviopsis paradoxa. Healthy plants were inoculated with the fungus and lesions developed demonstrating the pathogenicity of the isolate. Keywords: Ceratocystis paradoxa, Chalara, Cocos nucifera. The coconut tree (Cocos nucifera L.) is widely grown along the Northeastern coast of Brazil as well as in other areas of Brazil. There is a large and increasing demand for immature coconuts that are harvested and marketed for consumption of their liquid endosperm (coconut water). This is mostly supplied by dwarf variety plantations and average productivity has been limited in Brazil to around 3,400 fruits/hectare because of limited rainfall levels, pests and diseases (Cuenca, 1994). Warwick et al. (2004) noted the occurrence of what appeared to be a novel coconut disease for Brazil at Platô de Neópolis (State of Sergipe). About 50 coconut plants were observed to have symptoms of stem bleeding, a disease that was previously unrecorded in Brazil. RESUMOThe affected trunk areas exhibited dark discoloration and a reddish-brown or rust��colored liquid bleeding from different points (Figure 1). Diseased palms had reduced growth and a gradual but progressive necrosis of the lower pinnate leaf toward the midribs. Inside the stem, the tissues under the lesions were rotting and became brownish-yellow to black. Eventually the affected plants died. In every case, the plant showing symptoms was also being attacked by the weevil Rhynchophorus palmarum L. No attempt was made to treat the diseased plants, which died within 3-4 months of the observation of the early stem symptoms. Other biotic diseases that may be lethal to coconut palms in Brazil are: red ring, caused by the nematode Bursaphlelenchus cocophilus (Warwick & Bezerra, 1992); hartrot, caused by Phytomonas sp., a flagellate protozoa (Renard, 1989), and eye-rot caused by two species of Phytophthora (Quillec & Renard, 1984).In India, plants showing a similar disease were proven to be attacked by Thielaviopsis paradoxa (De Seynes) Höhn. (anamorphic Ceratocystidaceae). The studies in India showed that inoculation of healthy coconut plants with isolates obtained from diseased plants resulted in rusty brown discoloration of the bark within 2-8 weeks, followed by the oozing of a brownish liquid from stems. Re-isolation of T. paradoxa was made from such diseased tissues (Nambiar et al., 1986). Stem bleeding of coconut is known to occur in nearly all the countries which grow coconut (Ohler, 1964). The disease was first reported from Sri Lanka (Pe...

Notes on Ceratocystis paradoxa causing internal post-harvest rot disease on immature coconut in Brazil

“…This species was also reported causing post-harvest diseases in banana, carambola, guava and pineapple (Reyes et al, 1998;Junqueira et al, 2001;Ploetz, 2003). This pathogen causes stem bleeding (Warwick & Passos, 2009;Freire & Martins, 2010) and fruit basal rot of the coconut at field conditions (Rossetti, 1955;Camargo & GimenesFernandes, 1997;Tzeng & Sun, 2009;Tzeng et al, 2010) and external post-harvest disease on coconut (Tzeng & Sun, 2009;Tzeng et al, 2010). Thus, this is the first report of postharvest internal rot disease on immature coconut caused by C. paradoxa.…”

Diagrammatic scale of severity for postharvest black rot (Ceratocystis paradoxa) in coconut palm fruits

“…Symptoms in the fruits could vary according to the phenological stage, the environmental conditions and the diversity of the pathogen population since virulence in fruits is little known (15) Ceratocystis paradoxa incidence and damage to the Brazilian coconut crop have been apparently neglected until recently. Although it has often been the first cause of the disease in this country (25,26), Alves & Lourd (1) reported this fungus causing immature fruit drop and affecting coconut production. In the last century, disease outbreaks were reported in Rio de Janeiro State, causing black rot and stem bleeding, which became the first official record of this pathogenic association (17,6).…”

In vitro activity of essential oils of Lippia sidoides and Lippia gracilis and their major chemical components against Thielaviopsis paradoxa, causal agent of stem bleeding in coconut palms

“…The main stem-bleeding symptoms are reddish-brown liquid in the stem cracks, which may turn blackish when dried; reduced frequency of leaf emergence; reduced size of young leaves; stem thinning near the canopy as disease progresses; and brownish-yellow, easily breakable leaves. 1 Worldwide awareness of environmental damage caused by pesticides has driven the search for new measures to protect plants against diseases. Alternative control methods that can be used in an integrated manner to reduce the environmental impact of chemicals, 2 benefit both organic producers, who need more choices of products, and a large segment of consumers willing to pay for pesticide-free food.…”