Asst. Prof. Dr. Watcharra Chintakovid, Division of Agricultural Science, Kanchanaburi Campus, and Assoc. Prof. Dr. Aussanee Pichakum, Department of Plant Science, Faculty of Science, Mahidol University, provided knowledge on solving the problem of hot weather affecting the fruit setting of longan (Dimocarpus longan Lour.) orchard in Baan Phaeo, Samut Sakhon province.