Abstract: A laboratory test was conducted to study the control effect of parasiticMetaphycus parasaissetiae on its hostParasaissetia nigra. The functional reactions of the parasitism conformed to the Holling Type Ⅱ Equation, but the parameters of the functional reactions varied with temperature. Taking the ratio of instant attack rate to preying time (a/T_h) as an evaluation index, the preying efficiency at 30 ℃ was the highest, with a/T_h being 23.4211. There was a stronger interference effect in the functional reactions of the parasitism within M. parasaissetiae populations. With the increase of the population density, the amounts of parasitism decreased gradually. Hassell Equation (E=QP^-m) could describe the relationships between the searching efficiency of M. parasaissetiae and its population density much precisely within the range of 21 ℃-33 ℃. The interference increased with temperature within the range of 21 ℃-27 ℃, and the interference coefficient reached the highest (0.6626) at 27 ℃. When the temperature was raised to 30 and 33 ℃, the interference coefficient decreased to 0.6161 and 0.5916, respectively. In the prophase of egg-laying, the parasitized P. nigra could be entirely controlled by M. parasaissetiae. However, when a few larvae were crawling out, the control effect was declined to 81.4%.

Key words:  Parasaissetia nigra, Metaphycus parasaissetiae, functional response, interference effect, control effect, short-term continuous lighting with LED, nitrogen level, nitrogen form, hydroponic lettuce, nutritional quality.