Feeding and development of Spodoptera exigua (Hubner) (Lepidoptera: Noctuidae) on different host of medicinal plants (Orthosiphon stamineus, Gynura procumbens, Cantella asiatica and Capsicum frutescens)

Beet armyworm, Spodoptera exigua is a well-known insect pest of various crop plants, commercial trees, ornamental plants and flowers. This insect has a wide range of host plants around the world, therefore it has a potential to become pest of medicinal plant plantations in commercial use. A study was conducted to determine the suitability of four medicinal plant species as host plants: Gynura procumbens (Sambung Nyawa), Cantella asiatica (Pegaga Daun Besar), Orthosiphon stamineus (Misai Kucing) and Capsium frutescens (Cili Api), for the growth and development of beet armyworm. The fresh host plant leaves each species with the fix size (2½ cm diameter) were given to fed at the first instars of larvae until the pre-pupation stage. Based on the survival and mortality rates, developmental time, and pupae weight, G. procumbens was found more suitable for faster growth and development of larvae compared to O. stamineus which had survived only for nine days. Duration of the larval stage development was shortest on G. procumbens which only 9.11 days and longest on C. asiatica which 15.03 days. But numbers of survival are highest on C. asiatica, 24% and lowest on G. Procumbens, 13%. Whereas, the larvae on O. stamineus failed to survive. Over all, the arrangement suitability of the host plants were G. procumbens > C. frutescens > C. asiatica > O. stamineus. The physical and chemical characteristic of these different host plants may influence the differences of development and growth of S. exigua larval. The finding of this study can be used to estimation for controlling this insect to become pest in medicinal plant plantations if it was going to commercial planted.