Problem statement:The increasing of dragon fruit (Hylocereus spp.) plantations in Malaysia enhances the researches on this crop, particularly focusing on its physico-chemical characteristics, great potential health benefits and nutritional value. However, its scientific report of disease is still lacking, primarily on anthracnose disease. This study was then conducted to investigate the distribution of anthracnose disease on dragon fruit and to correlate its occurrence with weather and cultural data. Approach: Survey and sampling were conducted on dragon fruit-growing areas in Peninsular Malaysia since December 2007 until August 2008 to measure the Disease Incidence (DI) and Disease Severity (DS). The diseased stem and fruit were sampled and brought to laboratory for isolation and identification. DI data were plotted with DS and then correlated using Pearson correlation with weather and cultural data. Results: Of the 43 surveyed-farms in 11 states, DI and DS were successfully recorded on three dragon fruit species from 36 farms (83.72%). The infected stem and fruit had reddish-brown lesions with chlorotic haloes symptoms. The lesion had brown centers and coalesced to rot. Based on its whitish-orange colony, septated hypae and capsule-like conidia and the pathogenicity test, the pathogen was identified as Colletotrichum gloeosporioides. One way ANOVA with DMRT test highlighted that the most disease occurrence was found in Malacca (mean of DI and DS, 57.30 and 21.20%), whereas the lowest in Kelantan state (mean of DI and DS, 6.70 and 4.30%). Pearson coefficient correlations were around 0.107-0.261 for relationships between disease occurrence and age of crops and acreage of farm, from-0.049 to-0.237 for disease prevalence with relative humidity and rainfall and around-0.012-0.173 for disease occurrence with monthly temperature, wind velocity and altitude. Conclusion: The occurrence of anthracnose on dragon fruit in Peninsular Malaysia was more influenced by environmental conditions and agricultural practices rather than climatic factors.

Problem statement:The increasing of dragon fruit (Hylocereus spp.) plantations in Malaysia enhances the researches on this crop, particularly focusing on its physico-chemical characteristics, great potential health benefits and nutritional value. However, its scientific report of disease is still lacking, primarily on anthracnose disease. This study was then conducted to investigate the distribution of anthracnose disease on dragon fruit and to correlate its occurrence with weather and cultural data. Approach: Survey and sampling were conducted on dragon fruit-growing areas in Peninsular Malaysia since December 2007 until August 2008 to measure the Disease Incidence (DI) and Disease Severity (DS). The diseased stem and fruit were sampled and brought to laboratory for isolation and identification. DI data were plotted with DS and then correlated using Pearson correlation with weather and cultural data. Results: Of the 43 surveyed-farms in 11 states, DI and DS were successfully recorded on three dragon fruit species from 36 farms (83.72%). The infected stem and fruit had reddish-brown lesions with chlorotic haloes symptoms. The lesion had brown centers and coalesced to rot. Based on its whitish-orange colony, septated hypae and capsule-like conidia and the pathogenicity test, the pathogen was identified as Colletotrichum gloeosporioides. One way ANOVA with DMRT test highlighted that the most disease occurrence was found in Malacca (mean of DI and DS, 57.30 and 21.20%), whereas the lowest in Kelantan state (mean of DI and DS, 6.70 and 4.30%). Pearson coefficient correlations were around 0.107-0.261 for relationships between disease occurrence and age of crops and acreage of farm, from-0.049 to-0.237 for disease prevalence with relative humidity and rainfall and around-0.012-0.173 for disease occurrence with monthly temperature, wind velocity and altitude. Conclusion: The occurrence of anthracnose on dragon fruit in Peninsular Malaysia was more influenced by environmental conditions and agricultural practices rather than climatic factors.

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This study was carried out to identify the suspected pathogenic microorganisms associated with anthracnose disease on dragon fruit (Hylocereus spp.) and to investigate the occurrence of this disease in Peninsular Malaysia. Fifty posts of dragon fruit crops from several surveyed dragon fruit-growing areas were randomly sampled to assess the disease occurrence. The results revealed that anthracnose, caused by Colletotrichum gloeosporioides (Penz.) Penz. & Sacc., was one of the main diseases on this crop. This disease not only infected the stem but also the fruit. Diseased stem and fruit had symptoms of reddish-brown lesions with chlorotic haloes. The lesion had brown centers and coalesced to rot. Identification of the isolated pathogen showed that it had a whitish-orange colony, septated hyphae and capsule-like conidia (6-10 µm × 2-2.5 µm in size). The highest disease incidence (80%) was recorded from Pekan (Pahang), a farm with unfavorable environmental condition for the optimum growth of dragon fruit crops; while the most severe disease (32.0%) was documented from a Durian Tunggal (Malacca) farm where the crop hygiene was poor. Correlation of disease incidence and severity showed a positive linear correlation with an R2 value close to 1; while regression analysis results highlighted that the occurrence and progress of disease were highly influenced by environmental conditions, alternative sources of inoculum and agricultural practices rather than by climatic factors.