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Borer Attack (borer + attack)
Selected AbstractsEffects of predatory ants on lower trophic levels across a gradient of coffee management complexityJOURNAL OF ANIMAL ECOLOGY, Issue 3 2008S. M. Philpott Summary 1Ants are important predators in agricultural systems, and have complex and often strong effects on lower trophic levels. Agricultural intensification reduces habitat complexity, food web diversity and structure, and affects predator communities. Theory predicts that strong top-down cascades are less likely to occur as habitat and food web complexity decrease. 2To examine relationships between habitat complexity and predator effects, we excluded ants from coffee plants in coffee agroecosystems varying in vegetation complexity. Specifically, we studied the effects of eliminating ants on arthropod assemblages, herbivory, damage by the coffee berry borer and coffee yields in four sites differing in management intensification. We also sampled ant assemblages in each management type to see whether changes in ant assemblages relate to any observed changes in top-down effects. 3Removing ants did not change total arthropod densities, herbivory, coffee berry borer damage or coffee yields. Ants did affect densities of some arthropod orders, but did not affect densities of different feeding groups. The effects of ants on lower trophic levels did not change with coffee management intensity. 4Diversity and activity of ants on experimental plants did not change with coffee intensification, but the ant species composition differed. 5Although variation in habitat complexity may affect trophic cascades, manipulating predatory ants across a range of coffee agroecosystems varying in management intensity did not result in differing effects on arthropod assemblages, herbivory, coffee berry borer attack or coffee yields. Thus, there is no clear pattern that top-down effects of ants in coffee agroecosystems intensify or dampen with decreased habitat complexity. [source] Incidence and severity of marine borer attack at different depths at Mtongwe Jetty Pontoon Mombasa, KenyaAFRICAN JOURNAL OF ECOLOGY, Issue 4 2009P. K. Sirmah Abstract The activity of marine borers was investigated at Mtongwe Jetty Pontoon, Mombasa, Kilindini harbour using untreated panels of Pinus patula (Schlecht) submerged to different depths. Twenty test panels replicated over 7 months were each strung in three ladder-like frames using nylon twine and suspended vertically, in such a way that the top most panels were 25 cm below the water surface at low and high tide. Monthly observations were made between January and July for the vertical incidence and extent of marine borer attack following the technique of Bobat (1995). Marine borers were collected from test panels, identified and counted. In addition, the percentage weight loss for panels at different depths was determined at the end of 7 months. Teredo fulleri (Clapp) was dominant on panels near water surface while Martesia striata (Linne) and Lyrodus pedicellatus (Quatrefages) were predominant at the bottom. The results showed that attack began within the first month of exposure and was severest by the seventh month. The vertical incidence and extent of attack decreased with increasing depth of panel exposure and was negatively correlated with depth. This is attributed to changes in hydrographic conditions. Résumé L'activité des foreurs marins a étéétudiée dans le Ponton de Mtongwe Jetty, Mombasa, dans le port de Kilindini, en utilisant des panneaux de Pinus patula (Schlecht) non traités, plongés à différentes profondeurs. Vingt panneaux tests identiques ont été attachés avec des cordes de nylon pour former trois cadres ressemblant à des échelles et suspendus pendant sept mois verticalement de façon à ce que les panneaux supérieurs se trouvent à 25 cm sous la surface à marée basse et haute. L'on a fait des observations mensuelles entre janvier et juillet de l'occurrence verticale et l'étendue de l'attaque des foreurs marins en utilisant la technique de Bobat (1995). Les foreurs marins ont été collectés sur les panneaux tests, identifiés et comptés. De plus, on a déterminé le pourcentage de la perte de poids des panneaux aux différentes profondeurs à la fin des sept mois. Teredo fulleri (Clapp) était dominant sur les panneaux situés près de la surface de l'eau alors que Martesia striata (Linné) et Lyrodus pedicellatus (Quatrefages) étaient prédominants en profondeur. Les résultats ont montré que l'attaque a commencé dès le premier mois et que c'est alors qu'elle fut la plus sévère. L'occurrence verticale et l'étendue de l'attaque diminuaient quand le panneau était plus profond et étaient négativement liées à la profondeur. Cela est attribué aux changements des conditions hydrographiques. [source] Rind puncture resistance in maize: inheritance and relationship with resistance to pink stem borer attackPLANT BREEDING, Issue 5 2002A. Butrón Abstract The main pest of maize in north-western Spain is the pink stem borer, Sesamia nonagrioides, and stem lodging is one of the consequences of attack. Since rind puncture resistance is related to stem lodging resistance, the objectives of this work were to estimate the genetic effects involved in the inheritance of rind puncture resistance and to determine the phenotypic correlation coefficients between rind puncture resistance and pink stem borer damage. Six generations from the crosses ,CM109'×,EP31' and ,CM109'×,EP42' and a 10-inbred line diallel were evaluated in Pontevedra, Spain, in 1995 and 1996. The inheritance of rind puncture resistance had two significant components, one additive and one dominant. Non-allelic and genotype × environment interactions were not significant. Improvement for internode rind puncture resistance to increase stem strength and stalk lodging resistance could have some positive influence on resistance to pink stem borer. However, its use as an estimator of pink stem borer resistance cannot be generalized and so must be restricted to programmes that involve materials exhibiting physical resistance to pink stem borer attack. [source] Effects of selection for resistance to Sesamia nonagrioides on maize yield, performance and stability under infestation with Sesamia nonagrioides and Ostrinia nubilalis in SpainANNALS OF APPLIED BIOLOGY, Issue 3 2010G. Sandoya A maize synthetic population was improved for resistance to the Mediterranean corn borer (MCB, Sesamia nonagrioides) while maintaining yield. The objectives of this research were to investigate whether yield and yield stability of the maize synthetic population named EPS12 were affected by selection for MCB resistance; also to determine which genotypic and environmental covariates could explain the genotype (G), environment (E) and genotype × environment (GE) effects for yield under corn borer infestation. Plants from three cycles of selection and their testcrosses to three inbred testers (A639, B93 and EP42) were evaluated at two locations in 2 years, under MCB and European corn borer infestations. After selection EPS12 was a more stable genotype. Hybrids derived from crosses between B93 and inbreds obtained from the initial cycles of selection could be recommended for cultivation in northern Spain. The yield of crosses between cycles of selection and testers increased when there were fewer days with temperatures >25°C and higher mean maximum temperatures. Differences in yield among these genotypes were mostly explained by resistance to corn borer attack. In general, among EPS12-derived materials, genetic characteristics that contribute to increased grain yield were also responsible for increased abiotic stress tolerance. [source] | ||||||||||