Antifungal Effects of Senescence Terminalia Cattappa Leaves Extract on Disease Pathogens Associated With the Infestation of Hypsipyla robusta on Khaya grandifoliola

The causal organisms responsible for leaf blight and twig dieback on the saplings of Khaya grandifoliola infested with Hypsipyla robusta were investigated. Isolation of pathogens and subculturing of isolates from infested K. grndifoliola tissues were carried out using Potato Dextrose Agar (PDA). The inhibitory effects of T. cattapa leaves on the mycelial growth of identified pathogens were carried at different concentration of grounded T. cattapa leaves (0.0g 2g, 4g, 8g, and 10g) per litre of standard PDA medium in five replicates using CRD. One way ANOVA was carried out on data obtained from the radial measurements of mycelia growths on each pathogen (α = 0.05), and mean separations was done using LSD. Identified isolates from leaf blight were Rhizoctonia sp. and Colletotrichum sp. The isolates from the twig dieback were Fusarium sp. Fusarium sp radial mycelial varied significantly (P < 0.05) among the control, 4.0g/l, 6.0g/l, while there was no significant difference (p > 0.05) between the control and 10.0g/l. The highest percentage inhibition for Fusarium sp. was observed on 4.0g/l. Also, radial mycelial growth of Rhizoctonia sp varied significantly (P < 0.05) between 4.0g/l and other concentration levels while maintaining the highest percentage (7.17%) inhibition. Therefore, it was concluded that pathogens responsible for leaf blight and twig dieback of Khaya grandifoliolia trees following the infestation of Hypsipyla robusta were Rhizoctonia sp and Fusarium sp, respectively. The study also revealed that T. cattapa senescence leaves liquid extracts has the potency of controlling the pathogens.

Phytotherapy and Polycyclic Logging: Implication on Genetic Multiplicity and Diversity of African Mahogany in Tropical Rainforest

There are over 8,000 globally threatened tree species. For each species, there is a different story behind why they are threatened and what values we stand to lose if we do not find the means to save them. Mahogany, a member of Meliaceae, is a small genus with six species. Its straight, fine and even grain, consistency in density and hardness makes it a high valued wood for construction purposes. The bitter bark is widely used in traditional medicine in Africa. The high demand for bark has also led to the total stripping of some trees, complete felling of larger trees to get the bark from the entire length of the tree and bark removal from juvenile trees. These species are now threatened with extinction due to selective and polycyclic logging, and also excessive bark removal. The natural regeneration of mahogany is poor, and mahogany shoot borer Hypsipyla robusta (Moore) attacks prevent the success of plantations within the native area in West Africa. In developing countries, most of the Khaya species exists in the wild state; therefore, the regeneration and long-term conservation are at the mercy of the vagaries of nature and the profit driven herb collectors and timber merchants. It becomes urgently necessary by government of developing countries to place ban on further harvesting of mahogany species to allow the remaining few trees of mahogany in the forest to recuperate and produce substantial seeds for regeneration.