[Population growth, distribution pattern and sampling technique of Thrips palmi on eggplant]

Population growth of Thrips palmi Karny on eggplant (Solanum melongena L.) were analyzed by mathematical models. The rate of population increase (r) of the adults and immature (instars 1-2) T. palmi were estimated to be 0.0630 and 0.0801 respectively in the open fields, and 0.0983 and 0.1036 respectively in the greenhouse. K value of logistic curve of T. palmi was estimated to be 33.90 in the greenhouse, and 23.50 in the open fields. The relationship between mean crowding (M*) and mean density (M) of T. palmi per eggplant leaf were estimated by Iwao's M*-M regression. The regression equation of adult and immature T. palmi on eggplant were: M* = 0.6011 + 1.468M and M* = 7.2515 + 2.064M respectively. The regression equation of the number of adult and immature was M* = 7.5138 + 1.9119M. When the population density of the adults and immature T. palmi per eggplant leaf were 10 to 100, the number of sampling should be 78 to 44.