Influence of Light on Reproductive Rates of Asian Citrus Psyllid (Hemiptera: Liviidae)

The impact of light on reproductive rates of Asian citrus psyllid (Diaphorina citri Kuwayama) was assessed in an air-conditioned, polycarbonate greenhouse. This psyllid is an important pest because it transmits a bacterium presumed responsible for a serious citrus disease known as Asiatic huanglongbing. Numbers of psyllids produced were compared among rearing cages subjected to different amounts of light provided by natural sunlight and light-emitting diode floodlights. Light to some rearing cages was purposely reduced by shading. The cages received a daily mean of 12 h of light (range 7 to 14 h) during immature development. Irradiance during daylight hours in the cages during a 24-h oviposition period varied from 2 to 145 (mean 66) W/m(2) and during immature development to the adult stage from 3 to 169 (mean 71) W/m(2). Estimates of illuminance during immature development ranged from 354 to 73,500 (mean 22,409) lumens/m(2). Oviposition rates were not correlated with these light variables. Numbers of adults produced were positively correlated with daily hours of light (r = 0.57, P = 0.002), irradiance (r = 0.39, P = 0.05), and illuminance (r = 0.59, P = 0.001). For producing large numbers of adults, optimal targets for these light variables as measured in this study were projected to be 14 or more hours of daylight, 60 or more W/m(2), and 20,000 or more lumens/m(2). Comparisons of oviposition rates and resulting numbers of adults produced in a cage indicated that increasing these light variables increased survival of immatures to the adult stage, possibly because the quality of host plants increased as these light variables increased.