Verbena x hybrida and Scaevola aemula flowers provide nutrients for the reproduction of Nesidiocoris tenuis used for biological pest control in greenhouses

摘要

Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae) is a zoophytophagous mirid that can also feed on the plants upon which its prey lives. It is a generalist predator feeding on whiteflies, thrips, aphids, and other pests. The use of alternative plants as banker plants is recommended to aid the establishment of released natural enemies in greenhouses. If N. tenuis populations reproduce only on banker plants, the use of alternative hosts or prey to rear N. tenuis will be unnecessary, which makes the banker plant system easier to manage. Verbena x hybrida Voss (Lamiales: Verbenaceae) cv. Tapien and Scaevola aemula R. Br. (Asterales: Goodeniaceae) are recommended banker plants in Japan. This study examined the development, survival, and oviposition of N. tenuis on these two plant species in the laboratory, with and without flowers. N. tenuis performed similarly on both plants. The intrinsic rate of increase was slightly higher on Verbena x hybrida than S. aemula. The sugars in water samples collected from flowers of both plant species were analyzed using high-performance liquid chromatography. Fructose and glucose were detected in Verbena x hybrida, while fructose, glucose, and sucrose were detected in S. aemula. The total amount of sugars per ten flowers was much higher in Verbena x hybrida. These sugars, possibly derived from floral nectars, are considered as nutrients promoting the reproduction of N. tenuis, in addition to pollen. Verbena x hybrida and S. aemula both facilitate N. tenuis reproduction and can be used as banker plants.