Integrated pest management of Hypsipyla robusta shoot-tip borer (Lepidoptera: Pyralidae) in Chukrasia tabularis (Sapindales: Meliaceae).

Chukrasia tabularis A. Juss produces a valuable timber but plantations are susceptible to attack by the shoot-tip borer Hypsipyla robusta Moore. An integrated pest management (IPM) approach is desirable to limit the extent of damage. Therefore, this study was undertaken to evaluate the deployment of IPM measures in plantations in Vietnam. Data on tree damage and the biology of H. robusta were gathered in 4 provinces over one year and used to build an investigation schedule. Two preliminary IPM trials were then established in which Bacillus thuringiensis and Metarhizium anisopliae were applied to the foliage when the damage incidence (P%) was in the range 5-10%; and insecticides (Carbaryl, Carbosulfan) were applied when the P% exceeded 10%. In addition, larvae and pupae were removed manually over time. In the first trial, the combination of manual and biological control methods reduced the damage index (DI) of trees from 4 tolerant families by 82% compared to the untreated control plots. In the second trial using standard planting stock, application of insecticides was required to reduce the DI by 83%. Six extended IPM trials were undertaken using the same IPM protocols and these reduced the DI to the same extent as in the preliminary trials. Over an 18-month period, the deployment of IPM increased height growth by 19-22% and diameter growth by 38-41% compared to the controls. These findings highlight the value of planting improved seed and the benefit of adopting an IPM approach to manage the shoot-tip borer.

Identification, pathogenicity and abundance of Paracremonium pembeum sp. nov. and Graphium euwallaceae sp. nov.--two newly discovered mycangial associates of the polyphagous shot hole borer (Euwallacea sp.) in California.

Fusarium euwallaceae is a well-characterized fungal symbiont of the exotic ambrosia beetle Euwallacea sp. (polyphagous shot hole borer [PSHB]), together inciting Fusarium dieback on many host plants in Israel and California. Recent discoveries of additional fungal symbionts within ambrosia beetle mycangia suggest these fungi occur as communities. Colony-forming units of Graphium euwallaceae sp. nov. and Paracremonium pembeum sp. nov., two novel fungal associates of PSHB from California, grew from 36 macerated female heads and 36 gallery walls collected from Platanus racemosa, Acer negundo, Persea americana and Ricinus communis. Fungi were identified based on micromorphology and phylogenetic analyses of the combined internal transcribed spacer region (nuc rDNA ITS1-5.8S-ITS2 [ITS barcode]), elongation factor (EF 1-α), small subunit (18S rDNA) sequences for Graphium spp., ITS, EF 1-α, calmodulin (cmdA), large subunit of the ATP citrate lyase (acl1), ß-tubulin (tub2), RNA polymerase II second largest subunit (rpb2) and large subunit (28S rDNA) sequences for Paracremonium spp. Other Graphium spp. recovered from PSHB in Vietnam, Euwallacea fornicatus in Thailand, E. validus in Pennsylvania and Paracremonium sp. recovered from PSHB in Vietnam were identified. F. euwallaceae was recovered from mycangia at higher frequencies and abundances in all hosts except R. communis, in which those of F. euwallaceae and P. pembeum were equal. P. pembeum was relatively more abundant within gallery walls of A. negundo and R. communis. In all hosts combined F. euwallaceae was relatively more abundant within PSHB heads than gallery walls. All three fungi grew at different rates and colonized inoculated excised stems of P. americana and A. negundo. P. pembeum produced longer lesions than F. euwallaceae and G. euwallaceae on inoculated avocado shoots. Results indicate PSHB is associated with a dynamic assemblage of mycangial fungal associates that pose additional risk to native and nonnative hosts in California.

Fungal biogeography. Global diversity and geography of soil fungi.

Fungi play major roles in ecosystem processes, but the determinants of fungal diversity and biogeographic patterns remain poorly understood. Using DNA metabarcoding data from hundreds of globally distributed soil samples, we demonstrate that fungal richness is decoupled from plant diversity. The plant-to-fungus richness ratio declines exponentially toward the poles. Climatic factors, followed by edaphic and spatial variables, constitute the best predictors of fungal richness and community composition at the global scale. Fungi show similar latitudinal diversity gradients to other organisms, with several notable exceptions. These findings advance our understanding of global fungal diversity patterns and permit integration of fungi into a general macroecological framework.

Threat to cedar, Cedrela odorata, plantations in Vietnam by the weevil, Aclees sp.

The recent decline and death of young cedar, Cedrela odorata L. (Sapindales: Meliaceae), plantations in Vietnam is caused by Aclees sp. (Coleoptera: Curculionidae), a wood-boring brown weevil. A field study was undertaken in three-year-old plantations in two districts in Thanh Hoa province in August 2008. Trees were heavily impacted by the weevil, Aclees; the infestation level (P) ranged from 80 to 100% and the average damage index (R) ranged from 1.8 to 2.8. Observations over one year enabled the life history to be determined. Eggs were laid (February to March, September to November) inside the bark from the base of the trunk up to 60 cm in height. Larvae formed extensive feeding tunnels in the inner bark and sap wood. Pupation occurred in feeding tunnels or pupal chambers in the sapwood. Adults emerged twice a year, February to March and August to October. It is concluded that Aclees is a threat to C. odorata plantations in tropical regions of the world, and quarantine measures should be implemented to reduce the risk of spread.