Experimental studies on behavioral differences among three noctuid species larvae, Agrotis ipsilon, Mamestra brassicae, and Spodoptera litura in relation to the efficacy of a commercial bait

• Published in: Japanese Journal of Applied Entomology and Zoology Vol. 19; no. 1; pp. 11 - 16
• Main Authors: YOKOI, Shinji, OMINO, Teiji, TSUJI, Hideakira
• Format: Journal Article
• Language: Japanese
• Published: JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY 1975
• ISSN: 0021-4914; 1347-6068
• DOI: 10.1303/jjaez.19.11

Behavioral differences among three noctuid species larvae were experimentally investigated in relation to the efficacy of a commercial bait (Nekiriton® Sankyo Co., Ltd., Tokyo) against three species. The order of efficacy of the poison bait granules (containing 1% trichlorfon), when placed on soil surface, was A. ipsilon>S. litura>M. brassicae. However, the efficacy order differed with that of trichlorfon EC as well as that of isoxathion EC when applied on leaves of Chinese cabbage. In this case, the order of efficacy was A. ipsilon=M. brassicae>S. litura. The order of earliness of the developmental stage at which the larvae begin to enter into soil was A. ipsilon≥M. brassicae>S. litura, suggesting that the excellent efficacy of the poison bait against A. ipsilon larvae was to some extent due to their marked behaviour concealing underground. The order of feeding preference for the bait granules was S. litura>A. ipsilon>M. brassicae. This indicates some possibility that the relatively lower efficacy of the poison bait against M. brassicae larvae is related to their feeding preference. The closest correlation, however, was found between the order of efficacy of the poison bait and that of readiness of the three species larvae leaving the leaves of the normal food plant. The occurrence of migration of S. litura and A. ipsilon larvae from a leaf to another leaf was less dependent on the rearing density of the larvae before the experiment, but was much dependent on the larval density during the experiment. M. brassicae, on the other hand, hardly migrated as far as the leaf was suitable as their food even if the larval density was high before and during the experiment. These results suggest that density-dependent field migration of S. litura and A. ipsilon larvae may occur considerably before the complete consumption of their food plant, whereas that of M. brassicae larvae may be induced by the nearly complete food consumption.