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

Abstract

Studies on damage by larvae of Eldana saccharina Walker, Chilo zacconius Bleszynski and Sesamia spp. to sugar-cane stands revealed a high degree of correlation between internode damage and stalk damage as well as between internode damage and sugar content of the canes. For every 1% increase in stalk damage there was a corresponding increase of 0.214% in the internode damage. The distribution of larvae inside the internodes was found to depend on the level of infestation. At low field infestation level (below 25 larvae per 100 canes) the distribution was random. As the level of infestation increases, the distribution becomes more aggregated. The distribution of damage in the sugar-cane field was found to depend on the overall stalk damage. The distribution tends to be more contagious when field level of stalk damage was less than 45%. The damage became evenly distributed when stalk damage rose above 60%. An estimation of average loss of sugar caused by stem-borers to the variety NCO 376 (at the field damage rate of 8.6, 10.6 and 3.1% damage for bottom, middle and top parts respectively of the cane) was U.S.S332.10 per ha of field.Resume-Une etude des extraits de travaux sur le degat cause par des larves d' Eldana saccharina Walker, Chilo zacconius Bleszynski et Sesamia spp. aux plantes de canne a Sucre a revele un degre eleve de correlation entre d' une part le dommage a l'entre-noeud et celui du trognon, et d'autre part le dommage a l'entre-noeud et le contenu sucrier des Cannes. A chaque augementation d'un pourcent de dommage au trognon, correspondait une augmentation de 0,214% de dommage a l'entrenoeud. Il's est revele que la repartition des larves au long des entre-noeuds dependait du niveau d' infestation de ceux-ci. Lorsque le nivesu d' infestation du champ est bas (e'est-a-dire au-dessous de 25 larves sur 100 Cannes) la repartition des larves n'est pas reguliere. Par contre, lorsque le niveau d' infestation s' accroit, la repartition des larves devient plus agregee. On constate que l'ampleur du degat dans le champ de canne a sucre depend de 1' ensemble des dommages causes aux trognons. La repartition se revele plus contagieuse lorsque le taux du degat est inferieur a 45%. Lorsque le degat aux trognons atteignait plus de 60%

Effect of the stem borer Eldana saccharina (Lepidoptera: Pyralidae) on the yield of maize

“…The stem borer Eldana saccharina Walker, which is presumably of West African origin, was first described from Sierra Leone and has progressively spread towards East Africa (Appert, 1970). It probably occurs in all suitable areas of sub-Saharan Africa from approximately latitude 15°N to 30°S (Girling, 1978) and has been reported as an important pest of maize (Atkinson, 1980;Girling, 1978Girling, , 1980IITA 1986;Leyenaar & Hunter, 1977) and of sugarcane (Dick, 1945;Sampson & Kumar, 1985). E. saccharina females may lay their eggs on debris on the soil (Atkinson, 1980) or on the hairy margins of maize leaf sheaths (Cochereau, 1985).…”

“…Most studies reporting maize yield reduction figures in Africa are based on natural infestations by more than one species of stem borer (Adenuga, 1983;Adeyemi et al, 1966;Sampson & Kumar, 1985). In Nigeria, yield losses caused by stem borers have been estimated to range between 10% to 100% (Usua, 1968).…”

Stem borer herbivory dependent on interactions of sugarcane variety, associated traits, and presence of prior borer damage

“…68 (3) Does prior conspecific damage increase the risk that the same stalk will experience damage later within the same ratoon? Given that volatiles emitted from SCB-damaged stalks and conspecific frass attract more SCB in Brazil 32,33 and that conspecific damage caused by other borer species is correlated with increased damage in tropical growing regions, 69,70 we expected that existing SCB damage would increase the probability of subsequent SCB damage. (4) Do varietal differences in SCB damage align with particular plant traits?…”

Effect of Storage under Low Temperature on Pupal Duration and Adult Emergence of S. inferens

“…Maximum emergences of 84.33 per cent was recorded when pupae were exposed to 10 0 C for five days and the emergence was however reduced to 52.67 per cent when pupae were exposed to 15 days. (Sampson and Kumar, 1984). For the study of pink stem borer life cycle and behavior life stages are needed particularly eggs and pupae which we can stored in minimum temperature to delay the emergence.…”