Biology and associated fungi of an emerging bark beetle pest, the sweetgum inscriber Acanthotomicus suncei (Coleoptera: Curculionidae)

Abstract

The sweetgum inscriber (SI) Acanthotomicus suncei Cognato is an emerging bark beetle pest that seriously damages American sweetgum trees (Liquidambar styraciflua) and Chinese sweetgum trees (L. formosana) in China. Since 2013, SI has killed more than 30,000 sweetgum trees in Shanghai and adjacent areas. In Shanghai, SI was observed to emerge from infested wood between April–September and exhibited two generations per year. Both the flying populations and those in colonized logs were female‐biased. After the parental adult initiates a gallery, the emergence of new adults required 73.4 ± 0.7 days at 30°C and 163.5 ± 0.9 days at 20°C. SI could not sustain population development at constant temperatures ≤15°C. The fungi Geosmithia spp. and Phaeoacremonium tuscanum were common associates of SI. The results suggest that SI has a long flight period, and its development is sensitive to low temperatures. Fungi associated with SI were not pathogenic to American sweetgum trees, but their presence may indirectly increase the probability of tree mortality. Our findings contribute to the prevention and control of this important emerging bark beetle pest.

Geosmithia Species Associated With Bark Beetles From Southern China, With the Description of Four New Species

“…(Table 1). Moreover, the abundant of Geosmithia species associated with Acanthotomicus suncei in the current study was also consistent with the frequent occurrence in Shanghai and Jiangxi (Gao et al 2021).…”

Estimating Potential Distribution of Sweetgum Pest Acanthotomicus suncei and Potential Economic Losses in Nursery Stock and Urban Areas in China

“…Increasing the number of survey sites would improve the accuracy of the prediction. Although there is only sparse data of SI in natural vegetation [8], we still successfully recorded it in a general survey and log traps in Fujian and Jiangxi. However, due to limited manpower or expenditure, there are still some areas at the southern and northern edges where the sweetgum tree naturally grow that were not surveyed.…”

“…Therefore, minimum temperature of the coldest month (Bio 06) was kept, and temperature seasonality (standard deviation * 100) (Bio 04) was abandoned. Because Bio 04 was strong correlation with Bio 06 and Bio 06 has a greater impact on its biology [8]. Six environmental variables were chosen for SI (Table S2): Precipitation of the warmest quarter (Bio 18), Precipitation of the driest quarter (Bio 17), Precipitation seasonality (coefficient of variation) (Bio 15), Precipitation of the driest month (Bio 14), Mean temperature of the warmest quarter (Bio 10) and Bio 06 in the models of MaxEnt.…”

“…However, it has a history of damaging native sweetgum trees in China since 1959 [6,7]. In recent years, increased awareness of SI and ongoing survey efforts have led to the detection of numerous SI populations in urban and nursery areas [8]. Investigations indicated that more than 30,000 sweetgum trees (Diameter at breast height (DBH)= 5-25 cm) in Shanghai had been killed by SI up to 2018 [5,6], while no effective management has been developed.…”

“…Meanwhile, SI is similar to other wood borer species where infested trees typically exhibit few or no external symptoms at low densities, or have symptoms easily confused with other tree pathogens [10][11][12]. Previous studies have focused on the emergence and developmental characteristics of SI adults in Shanghai as well as the fungi associated with SI in the field [8]. The infestations and identity of SI are rarely confirmed before tree mortality or wilt occurs [6].…”