Effects of Sargassum seaweed on larval development and oviposition of the Asian corn borer, Ostrinia furnacalis (Guenee) Lepidoptera: Crambidae)

Larva development, fecundity, hatchability of eggs and longevity of adult male and female Asian corn borer (ACB), Ostrinia furnacalis (Guenee), with and without Sargassum seaweed were investigated in the laboratory. There was slight variation in the mean total larval development periods (14.83 days in the treatment without seaweed and 15.73d with seaweed, in the male ACB). In the female, there was also very slight variation in mean total of larval development periods (14.83 days in the treatment without seaweed and 15.73d with seaweed, in the male ACB). In the female, there was also very slight variation in mean total larval periods (16.70 days in treatment without seaweed and 16.73d with seaweed). However, there was higher mortality of the larvae in the seaweed treatment (48%) and 37% in the control treatment (without seaweed). Moreover, there were more males (67.44%) than females (32.56%) in the seaweed treatment or a sex ratio of 2 males: 1 female. Conversely, in the control treatment, there were more females (56.60%) than males (43.4%) or a sex ratio or 1 male: 1.3 females. This may indicate the differential effect of seaweed on the female ACB causing in premature death which may have impact on reproduction. Females in the control treatment laid more and bigger eggmasses. Hatchability of eggs, on the average was 78.56% in the control and 72.06 in the seaweed treatment. In terms of post development of adult ACB female, particularly pre-oviposition, oviposition and post oviposition periods, there were only slight variations between the seaweed treatment and the control. Longevity of male adult ACB in the control treatment was shorter than in the seaweed treatment and this holds true with the females in the seaweed treatment. In general, results showed the Sargassum seaweed affected growth and development, fecundity and longevity of adult ACB.