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Eucryptorrhynchus scrobiculatus (Motschulsky) is a serious pest of tree of heaven, Ailanthus altissima (Mill.) Swingle in China. Laboratory choice tests were conducted to compare attractiveness of ...

Eucryptorrhynchus scrobiculatus (Motschulsky) (Coleoptera: Cuculionidae) is a borer that mainly attacks the tree of heaven, Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae), and is one of the most damaging forestry pests in China. We developed a trap net for entangling and immobilizing soil-emerging weevils in order to reduce their impact. Recapture rates of weevils in the laboratory was significantly higher with nylon netting of 9, 10, or 11 mm mesh sizes than larger sizes, and these sizes were used to make trial nets for preventing weevil emergence from the soil around impacted trees in the field. Nets were 2 × 2 m with a reinforced border and Velcro-closable, radial slit which allowed the net to be arranged around the base of the tree while producing an unbroken barrier beneath the soil surface (i.e., a modified square trap net, MSTN). Recapture rates of weevils released in the soil did not differ among the MSTNs of 9, 10, or 11 mm mesh sizes. MSTN treatments significantly reduced emergence by naturally-occurring weevils from the soil surrounding trees and reduced numbers of weevils caught in population monitoring traps deployed in treated stands. The results demonstrated that MSTNs might be used to manage of E. scrobiculatus.

Eucryptorrhynchus brandti Harold is a trunk-boring pest of tree-of-heaven Ailanthus altissima (Mill.) Swingle in China, and is being studied in quarantine in the United States as a potential biolog...

Background Eucryptorrhynchus brandti (Harold) is a destructive wood-boring pest of tree of heaven, Ailanthus altissima, in China. At present, the management of E. brandti relies exclusively on frequent applications of synthetic insecticides. Environmentally friendly alternatives to the use of synthetic insecticides would be beneficial. A trunk trap net (TTN), an adhesive trap (AT), and an adhesive trunk trap net (ATTN) were evaluated in their ability to capture E. brandti. Results Significantly greater laboratory weevil recapture rates were found using the ATTN (78%) than using the TTN (8%) and AT (0%). In total, 45% of marked weevils were captured by the ATTN, an eight-fold increase in catch rates using the TTN in mark-release-recapture field trials in 2017. No marked weevils were captured by the AT. Field trials in 2017 and 2018 showed that the ATTN captured six to seven times more wild weevils than using the TTN. Conclusion Adhesive Trunk Trap nets (ATTNs) were more effective in capturing E. brandti adults than Trunk Trap nets (TTNs). These results support the use of the ATTN as an eco-friendly tool for the integrated management of E. brandti. © 2019 Society of Chemical Industry.

Background Eucryptorrhynchus scrobiculatus is a major pest of tree of heaven, Ailanthus altissima, in China. Damage caused by E. scrobiculatus has increased as beetle populations have expanded. We developed a trunk trap net (TTN) and two modified TTNs, that is, a TTN with a wire ring (TTN-WR) and a TTN with a spongy cushion (TTN-SC), and evaluated their ability to capture E. scrobiculatus in plantations of A. altissima. Results We obtained significantly higher laboratory weevil recapture rates using the TTN-WR and TTN-SC (98 and 95.3%, respectively) than using the TTN (65.3%). In total, 84.8 and 85.8% of marked weevils were captured by the TTN-WR and TTN-SC, respectively; 1.52- and 1.54-fold greater than the catch rates using a TTN in mark-release-recapture field trials. Similarly, we captured significantly more wild weevils using the TTN-WR and TTN-SC (2.02- and 2.03-fold more weevils) than using the TTN. Further field trials showed that the TTN-SC treatment significantly reduced densities of weevils and damage to tree of heaven in stands. Conclusion Our results revealed that the TTN-SC is clearly effective for capturing E. scrobiculatus. TTN-SC may be used as an alternative for E. scrobiculatus management with less or no insecticide. © 2019 Society of Chemical Industry.

Eucryptorrhynchus scrobiculatus and E. brandti (Coleoptera: Curculionidae) are host-specific pests of Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae), causing extensive damage to the host. There are no effective attractants available for pest management. The main aim of this study was to explore the role of host plant-derived volatiles in the behavioral response of both weevil species. In a field experiment, both weevil species showed positive response to phloem, and there was no preference for phloem associated with healthy or injured trees. Significantly more E. brandti adults responded to the olfactory treatments compared to E. scrobiculatus. In a large-arena experiment, both males and females of E. scrobiculatus significantly preferred phloem from the tree trunk while adults of E. brandti responded in significantly greater numbers to tree limbs than to any other parts of host. Females and males of E. scrobiculatus responded positively to all parts of host tested in the Y-tube bioassay, while E. brandti adults were only attracted by the phloem from healthy and injured trees. There were dissimilar electroantennographic responses to compounds such as 1-hexanol and (1S)-(&minus, )-&beta, pinene between the two weevil species. This study represents the first report documenting behavioral and electrophysiological responses of E. scrobiculatus and E. brandti to volatiles from various parts of A. altissima and findings may aid efforts to develop attractants.

Temperature is one of the most important abiotic factors that influences the development and growth of insects. We investigated the effect of temperature on the development of the weevil Eucryptorrhynchus brandti (Harold). The developmental zeros and effective accumulated temperatures for different developmental stages of E. brandti were estimated under variable temperatures in the laboratory. We observed that the developmental zeros of eggs, larvae, and pupae were 15.27 °C, 20.86 °C, and 14.04 °C, respectively, and the effective accumulated temperatures were 81.46 °C·d, 293.76 °C·d, and 127.76 °C·d, respectively. The rate of development increased as the temperature increased within a particular temperature range, and temperatures from 30 °C to 31 °C were particularly suitable for E. brandti rearing. Based on these results, we may be able to predict the occurrence of E. brandti, providing a reference for physical control measures targeting adults to effectively reduce oviposition and minimize population expansion.