Control of Eucryptorrhynchus scrobiculatus (Coleoptera: Cuculionidae), a Major Pest of Ailanthus altissima (Sapindales: Simaroubaceae), Using a Modified Square Trap Net

Developing traps for the overwintering tree-of-heaven weevils Eucryptorrhynchus scrobiculatus and E. brandti (Coleoptera: Curculionidae)

BACKGROUND

The tree-of-heaven root and trunk weevils, Eucryptorrhynchus scrobiculatus (TRW) and E. brandti (TTW) are important boring pests of Ailanthus altissima in China. Overwintering TRW and TTW adults can continue to damage A. altissima trees and reproduce after they emerge from the soil each year. There is a lack of studies regarding the development of control measures during the overwintering period. A polyethylene terephthalate bottle trap (PETBT) and corrugated paper box trap (CPBT) were evaluated for their ability to trap TRW and TTW adults descending from trees to overwinter in the soil in Wutongshu and Shabatou locations in Ningxia, China.

RESULTS

Significantly more overwintering TRW adults were caught by the PETBT than the CPBT. There were no significant differences in the TTW captures in PETBT when compared to the CPBT. Both PETBT and CPBT have little effect on trapping overwintering TTW adults. Further trapping studies showed that PETBT treatments significantly reduced overwintering TRW numbers caught in population monitoring trap nets placed on the A. altissima tree trunks (an average annual reduction of 42% than the untreated trees).

CONCLUSION

These results demonstrate that PETBT is effective for trapping overwintering TRW adults. PETBT could be recommended as an alternative for managing TRW in the framework of integrated pest management. © 2021 Society of Chemical Industry.

A novel adhesive trunk trap net for trapping Eucryptorrhynchus brandti (Coleoptera: Curculionidae)

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.

Efficacy of Trunk Trap Nets and Insecticides Applied Alone and in Combination for Control of Tree-of-heaven Root Weevil Eucryptorrhynchus scrobiculatus in Ailanthus altissima Plantations

In Northern China, the tree-of-heaven root weevil (TRW), Eucryptorrhynchus scrobiculatus (Motschulsky) (Coleoptera: Curculionidae), is a serious borer pest of Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae) (tree-of-heaven) is an important tree species for landscapes and afforestation. This study evaluates the efficacy of trunk trap nets (TTN), thiacloprid spray (TS), and cypermethrin spray (CS) alone, and in combination with TTN and thiacloprid or cypermethrin spray (TTNTS or TTNCS) for controlling TRW in A. altissima plantations in 2016–2018 in three sites (Haojiaqiao, Wutongshu, and Taojiajuan), which are located near Lingwu city in Ningxia, China. TTN, TTNTS, and TTNCS treatments significantly reduce marked TRW captures (more than 93% with respect to the untreated trees) and wild TRW captures in population monitoring trunk trap nets (MTTN) deployed in stands (more than 55% with respect to the untreated trees). Further field trials demonstrate that these TTN, TTNTS, and TTNCS treatments significantly reduce damage to A. altissima in stands; there are no significant differences between TTN and combination treatments. In addition, significantly more TRW are captured in MTTN within Taojiajuan than within Haojiaqiao or Wutongshu in field trials 2018. There were no significant differences between sites in 2016 and 2017. This study indicates that the TS and CS treatments used had very little to no impact on TRW populations and tree health in the timeframe examined. TTN alone are clearly effective for suppressing populations of TRW and stabilizing A. altissima tree health. This physical control technique, using TTN, could be sufficient to manage TRW on tree-of-heaven with no insecticide.

Novel trunk trap net designs for the control of Eucryptorrhynchus scrobiculatus (Coleoptera: Curculionidae)

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.