Mean (±SEM) captures of female <i>Euwallacea</i> nr. <i>fornicatus</i> in field tests conducted in a well maintained avocado grove in Miami-Dade County, FL.

<p>(A) 2-week test in Feb-Mar 2016. (B) 2-week test in May 2016. (C) 4-week test in Jun-Jul 2016. Lure treatments consisted of a quercivorol bubble lure and an α-copaene bubble lure, deployed separately and in combination in sticky panel traps. The control treatment consisted of an unbaited sticky trap. Bars topped with the same letter are not significantly different (Tukey HSD means separation, <i>P</i> < 0.05).</p

α-Copaene is an attractant, synergistic with quercivorol, for improved detection of <i>Euwallacea</i> nr. <i>fornicatus</i> (Coleoptera: Curculionidae: Scolytinae)

<div><p>The tea shot-hole borer, <i>Euwallacea fornicatus</i> Eichhoff, is an ambrosia beetle endemic to Asia and a pest of commercial tea, <i>Camellia sinensis</i> (L.) Kuntze. Recently, a complex of species morphologically similar to <i>E</i>. <i>fornicatus</i> has been recognized, which includes new pests established in Israel and the USA, both in California and Florida. Collectively termed <i>E</i>. nr. <i>fornicatus</i>, these cryptic species carry symbiotic <i>Fusarium</i> spp. fungi, some of which cause dieback disease in susceptible hosts, which include avocado, <i>Persea americana</i> Miller. Due to the threat to this economically important crop, research was initiated to evaluate efficacy of kairomone-based lures for detection of the beetle in Florida (termed the Florida tea shot hole borer, FL-TSHB). A series of field tests were conducted in 2016 in commercial avocado groves known to have FL-TSHB at various population levels. All tests evaluated lures containing quercivorol (<i>p</i>-menth-2-en-1-ol) and α-copaene, presented separately and in combination; and one test evaluated effect of trap type on beetle captures. In addition, electroantennography (EAG) was used to quantify female olfactory responses to lure emissions. This study identified (-)-α-copaene as a new attractant for FL-TSHB, equivalent in efficacy to quercivorol (the standard lure for <i>Euwallacea</i> detection in the USA); however, the combination of lures captured significantly more FL-TSHB than either lure alone. This combination resulted in synergistic attraction at two field sites and additive attraction at a third site. Sticky panel traps captured more FL-TSHB than comparably-baited Lindgren funnel traps. Females engaged in host-seeking flight from 11:00 to 16:00 hr (EST), with peak numbers observed between 12:00 and 13:00 hr. EAG analyses confirmed olfactory chemoreception of both kairomones, with a higher response elicited with the combination of volatiles. Results indicate that detection of pest <i>E</i>. nr. <i>fornicatus</i> in Florida can be improved by using a two-component lure consisting of <i>p</i>-menth-2-en-1-ol and (-)-α-copaene.</p></div

Scanning electron micrographs of antennae from female <i>Euwallacea</i> nr. <i>fornicatus</i>.

<p>(A) Ventral view of antenna, showing arrangement of sensilla in concentric rings on the apical end of antennal club (450 x magnification). (B) Lateral view of antenna, showing the diagonal elongation of the dorsal surface of the club and concentration of sensilla on the ventral surface (500 x magnification). (C) Portion of the lower concentric ring, showing two types of sensilla: long serrated sensilla trichoidea along the outer edge, and more numerous bluntly-ended sensilla basiconica throughout the interior (2000 x magnification). (D) Portion of the upper concentric ring, showing three types of sensilla: serrated sensilla trichoidea, blunt sensilla basiconica (with fine sculpturing), and shorter bulbous sensilla basiconica (with deep grooves) (5000 x magnification).</p

Summed captures of Scolytinae (Coleoptera: Curculionidae) from three field tests conducted in a well-managed avocado grove in Miami-Dade County, FL (8 wk total trapping effort, Feb-Jul 2016).

<p>Summed captures of Scolytinae (Coleoptera: Curculionidae) from three field tests conducted in a well-managed avocado grove in Miami-Dade County, FL (8 wk total trapping effort, Feb-Jul 2016).</p

Summed captures of Scolytinae (Coleoptera: Curculionidae) from an 8-wk field test conducted in an avocado grove affected by laurel wilt in Miami-Dade County, FL (Jul-Sep 2016).

<p>Summed captures of Scolytinae (Coleoptera: Curculionidae) from an 8-wk field test conducted in an avocado grove affected by laurel wilt in Miami-Dade County, FL (Jul-Sep 2016).</p

Mean (±SEM) captures of female <i>Euwallacea</i> nr. <i>fornicatus</i> in an 8-week field test (Jul-Sep 2016) conducted in a managed avocado grove with laurel wilt in Miami-Dade County, FL.

<p>Lure treatments consisted of a quercivorol bubble lure and an α-copaene bubble lure, deployed separately and in combination in sticky panel traps. The control treatment consisted of an unbaited sticky trap. Bars topped with the same letter are not significantly different (Tukey HSD means separation, <i>P</i> < 0.05).</p