Mycelia Growth and Sporulation of Phytophthora colocasiae Isolates under Selected Conditions

Abstract

This work was carried out at the International Institute of Tropical Agriculture (IITA), Yaoundé Nkol bisson. Ten improved and four local cultivars of taro were used to carry out a pathogenicity test of Phytophthora colocasiae isolates from which one virulent isolate from both improved cultivar BL/SM123, and BL/SM120, were selected and subsequently used in determining the effect of Original Research Article media, temperature, pH, and light on growth parameters-mycelia growth and spores density. There was a significant difference (P ≤ 0.05) on the growth media for the optimal fungal growth parameters. The most appropriate media for mycelia growth and spores production were V6 and V8 juice agar. The optimum temperature for mycelia growth and spore density was 24°C and also optimum pH value for spores production was 6. The selection of the best growth medium was important to screen the fungal pathogen for virulence and potential field pathogenicity testing. Incubation in both light and dark was best for mycelia growth and sporulation.

Field management of <i>Phytophthora</i> blight disease of cocoyam <i>Colocasia esculenta</i> L.) With spray regimes of selected fungicides in Nsukka, south eastern Nigeria

“…These were seen as small brown and water soaked lesions and sometimes with orange host exudation. This report was in line with the findings made by Onyeka ( 2011); Mbong et al(2013); and NRCRI (2012). Significant differences (P < 0.05) were revealed among the fungicides on growth parameters especially on number of leaves/stand Ridomil performed best among the fungicides followed by Ridomil+Champ.…”

“…Trujilo (1965) stated that taro disease was much related to temperature. Mbong et al (2013) stated that during the last quarter of 2009, symptoms suggestive of taro leaf blight were observed on taro across many southern regions in Nigeria, followed by a disappearance of symptoms with onset of dry season, but reappeared on the onset of rainy season.…”

“…Taro leaf bight was first described in Java (Indonesia) by Raciborski (1900). The first observation of taro leaf blight from Philippines was in 1916 (Gomez, (1925), Hawaii in 1941(Paris, 1941, Nigeria in 2009(National Root Crop Research Institute, NRCRI, 2012, and Cameroon in 2010 (Mbong et al, 2013). Over the years, the taro leaf blight has posed great challenges to taro farmers and researchers.…”

Cultural and Physiological Characterization of Phytophthora parasitica causing Foot Rot of Betelvine (Piper betle L.)

“…Mbong et al, (2015) reported that among the different pH levels, ranging from 6 to 8 supported the good growth of the P. colocasiae but the maximum growth was observed at pH 7 (85.30 mm) and least growth was recorded at pH 4 (66.00 mm).…”

“…These results were in conformity with the findings of Mounde et al, (2012) who reported that the colony diameter of 55 mm and 0 mm for P. citrophthora was observed at 24 o C and 35 o C respectively. Mbong et al, (2015) reported that optimum temperature for maximum growth of pathogen was 24 o C (72.30 mm).…”