Biology and damage traits of emerald ash borer (Agrilus planipennis Fairmaire) in China

Abstract

Emerald ash borer (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae) is a major stem borer of ash (Fraxinus spp.). It is univoltine in Tianjin, while it is semivoltine in Heilongjiang Province, and both univoltine and semivoltine in Changchun, Jilin Province, where the majority is univoltine. The longevity of emerald ash borer adults is 17.2 ± 4.6 days (n= 45), eggs 9.0 ± 1.1 days (n= 103), univoltine larvae 308 days, semivoltine larvae 673 days, and pupae 61.2±1.6 days (n= 45). It takes about 100 days from the time larvae bore into the phloem to when they complete the pupal cell. In a 10‐year‐old velvet ash (Fraxinus velutina Torr.) plantation in Tianjin, emerald ash borer preferred to oviposit on the regions of boles from 50‐150 cm above ground, accounting for 76.7% of the total girdling. Girdling on the south side of the tree boles accounted for 43.40% of the total girdling. The emerald ash borer population density is higher at the edge of the plantation compared with the center.

Scientific Opinion on a technical file submitted by the US Authorities to support a request to list a new option among the EU import requirements for wood of Agrilus planipennis host plants

“…In the province of Tianjin, China, situated next to the Yellow Sea coast, oviposition has been observed from early May to late June or early July (Wei et al, 2007;Wang et al, 2010). In Heilongjiang province, situated in the northern part of the country, oviposition has been observed from early June until early July (Wei et al, 2007). Oviposition usually takes place under bark flaps or in vertical slits on the trunk.…”

“…It has been observed that low density populations on vigorous ash trees tend to support a two year life cycle while stressed trees with higher beetle population densities tend to support a one year life cycle (Cappaert et al, 2005). Wei et al (2007) established a relationship between the duration of the frost free period in three provinces of China and the duration of the life cycle. It takes at least 150 frost free days (with minimum temperatures above zero degrees Celsius) for EAB to complete one generation.…”

“…It usually builds a pupal cell (overwintering chamber) in the xylem. When a two year life cycle is observed, second and third instar larvae may also overwinter in their galleries between the xylem and the phloem (Timms et al, 2006;Wei et al, 2007). Overwintering prepupae have low supercooling points reaching -30 °C, which are achieved by accumulation of high concentrations of glycerol and synthesis of antifreeze agents, contained in the haemolymph.…”

“…EAB has both a one and two year life cycle in China (Wei et al, 2007) and the United States (Cappaert et al, 2005). The duration of the life cycle may depend on various factors such as population density, climate, food quality, oviposition time, defensive response of the host, etc.…”

“…According to Wei et al (2007) the larval stage is the longest one of the life cycle of the insect with a duration of approximately 308 days for a one year cycle and 673 days for a two year cycle. It starts in late May and continues to mid-April the following year or early May the year after, respectively.…”