A prototype of nursery house (5×8×3.80 m) was established for producing disease free citrus propagation materials. The frame of prototype nursery house was made of galvanized pipe and it was covered with UV-resistance nylon net (32 mesh). Optimum temperature and relative humidity in the prototype nursery house were automatically controlled. It was compared with a commercial nethouse (6×9×4.40 m) and a shade house (4×6×2.50 m). The capacity of the prototype nursery house, commercial nethouse and shade house was assessed by growth determination of plants grown inside for 3 months. The plant materials used for testing were Troyer seedlings, Shogun mandarin mother plants and Neck orange nursery trees. It was found that the plants grown in the prototype nursery house and commercial nethouse exhibited significantly higher growth than those plants in the shade house. Differences of temperature and relative humidity in the prototype nursery house, commercial nethouse and shade house were evaluated. It was prominent that the temperature and relative humidity during the experimental period in the commercial nethouse were highest, while they were lowest in the shade house. An occurrence of canker diseases markedly increased in the commercial nethouse because of high humidity and temperature. Leaf destruction by main insect pests was a serious problem in the shade house. From the results, it is suggested that the prototype nursery house is suitable for producing disease free citrus propagation materials in southern Thailand.
