Life history, development and behaviour ofEldana saccharinaWalker on sugar-cane in southern Ghana

Abstract

Female Eldana saccharina Walker was found to lay 327 ± 17.1 eggs within a period of 4 days and required three surfaces to lay eggs which were mainly deposited on the inner side of leaf sheaths fitting tightly on to the sugar-cane stalk. The mated females laid more eggs per female (327.0 ± 17.1) than virgin females (212.3 ± 5.5). The incubation period of the eggs of E. saccharina was found to be 5.64 ± 0.01 (5–7) days in the laboratory and 5.82 ± 0.03 (5–7) days in the field. The mean larval duration was 31 days and pre-pupal period lasted 2.05 ± 0.05 days. Larvae were found to exude a brownish liquid from their mouth in the direction of the invading predators. The newly hatched larvae spread out in 1–3 days of hatching. The mean growth ratio of the larval instars was 1.54 ± 0.05. Pupae frequently occurred very close to the exit hole (less than 5 cm) and the pupal period varied from 7 to 13 (9.76 ± 0.05) days. The life cycle of E. saccharina was completed in 49 (36–62) days. The pre-oviposition period was 2 days and the female reproductive life lasted 4 days. It takes about 53 days for a succeeding generation to be produced. Adults of E. saccharina survived from 6 to 13 days. Adults reared from field collected larvae snowed a sex ratio of 42:51 which was significantly different from 1:1 in the laboratory bred stock, at the 5% level of probability. A comparison of the life cycle of E. saccharina populations in Ghana and Uganda suggests the existence of two biotypes of the pest.

Borer damage and estimation of loss caused by sugar-cane stem-borers in southern Ghana

“…However, Girling (1978) observed in Uganda that stem borer attack was more frequent in the lower than the higher part of the softer varieties, but more frequent in the younger, softer joints near the top than the lower joints in the harder varieties. These and other observations (Sampson and Kumar, 1985) tend to suggest the existence of biotypes of E. saccharina in different geographical areas.…”

General biology ofEldana saccharina(Lepidoptera: Pyralidae): A Target for the Sterile Insect Technique

“…In an earlier study by Dick (1945) females oviposited on average 750 eggs, with a maximum of 1004. Mating increased the number of eggs oviposited compared with unmated females (Dick 1945;Sampson & Kumar 1985). In West Africa, Betbeder-Matibet et al (1977) reported an average fecundity of 460 eggs oviposited per female, up to a maximum of 811 for females reared on an artificial diet.…”

“…In a later paper, Betbeder-Matibet (1981) reported similar fecundity but did not state if the females were reared on artificial diet or sugarcane stalks. In East Africa, Waiyaki (1974) reported an average fecundity of 150 to 230 eggs per female and Sampson & Kumar (1985) reported an average fecundity of 327 ± 17 eggs per female reared on sugarcane stalks. Sampson & Kumar (1985) compared adult longevity and life cycle lengths of E. saccharina from Ghana, West Africa with those reported by Girling (1978) from Kenya, East Africa.…”

Lepidopterous stem borers of maize (Zea mays): agro-ecological and regional composition and distribution of their parasitoids in Southern Ghana

“…Though egg scouts were made throughout the experimental period in the experimental farms, it was only during two occasions in the minor season that ten egg batches were collected. This could be due to the possibility that eggs were laid at spots of the plant where they were difficult to locate as reported by Sampson and Kumar (1985). No egg parasitoids were found probably due to the scanty number of the eggs collected.…”