Longan fruit rot and the influence of principally environmental factors on the disease in Ba Ria - Vung Tau province

Abstract

Investigation of longan fruit rot and the influence of principally environmental factors on the disease were carried out from June to October 2022 in Ba Ria - Vung Tau province, appropriately applying TCVN 13268-4:2021 on pests recording method on fruit trees to determine the yield loss by fruit rot during harvest season. While the Datalog 800019 thermo-hygrometer equipment was installed in the longan field before the disease emerged at 7 days to record temperature and humidity data throughout the survey period. The results show that fruit rot disease emerged on the xuong com vang, edor and tieu da bo longan varieties from the physiological maturity to the harvest stage. The longan fruit rot harmed from 20.83% to 22.92% of the clusters at emerging period. The disease was the most severe at the harvest stage with 45.42 - 74.17% of the damaged clusters. Longan varieties yield were lost from 1.15 tone per hectare to 2.96 tone per hectare at harvesting time. Therefore, the economic value loss caused by the disease from 33.13 to 59.27 million VND per hectare. The largest damage was on the edor variety, followed by the xuong com vang and tieu da bo respectively. The linear regression analysis shows a very firm and significant correlation between the longan fruit rot and humidity and rainfall. In which, humidity created the most influential on fruit rot of the xuong com vang and edor varieties during the rainy season in Ba Ria - Vung Tau province.