Snowdrop Lectin (GNA) Affects Growth and Development of Spodoptera exigua (Hubner)

Beet armyworm (Spodoptera exigua (Hubner)) (Lepidoptera: Noctuidae) is the most economically important sugar beet (Beta vulgaris) pest worldwide. The main control method of this pest is insecticides use. Thus, it is important to develop alternative means of controlling this pest, including host plant resistance using plant lectins. In the current study, the effects of GNA (Galanthus nivalis agglutinin) on the growth and development of beet armyworm were investigated using artificial diet. The presence of GNA in the diet at a level of 0.1, 0.25, 0.5 and 1.0% of the total dietary protein significantly reduced larval and pupal survivability compared with the control insects (P< 0.001). When high doses of GNA (0.5 and 1.0% of dietary protein) were incorporated into the diet, no larvae reached the fourth stadium. Only the lowest dose (0.1% GNA) allowed for larval and pupal development to continue to adult. The lectin retarded larval development in a dose dependent manner. For example, developmental time of the first instar larva in the control was 2.3 days, while in 0.1, 0.25, 0.5, and 1.0% GNA treatments this value increased to 2.6, 2.7, 2.8, and 2.9 days, respectively. Larval developmental time (time taken from neonate first instar larvae to pupation) in the control and lectin treatment (0.1% GNA) were 14.1 and 17.2 days, respectively. GNA also affected duration of pupal period, adult longevity, and adult emergence. In conclusion, it should be said that GNA has a good potential to be used in IPM program in order to combat this insect species.

Snowdrop Lectin (GNA) Affects Growth and Development of Spodoptera exigua (Hubner) Keywords:

beet armyworm , Galanthus nivalis , Growth