Chris T. Maier

Sex pheromone components of the spring hemlock looper,Lambdina athasaria (Walker) (Lepidoptera: Geometridae)

Two methylated hydrocarbons, 7-methylheptadecane (7) and 7,11-dimethylheptadecane (7,11), are female sex pheromone components of the spring hemlock looper (SHL),Lambdina athasaria (Walker). Compounds extracted from female pheromone glands were identified by coupled gas chromatographic-electroantennographic detection (GC-EAD) and coupled GC-mass spectrometry (GC-MS) in selected ion monitoring mode. In field trapping experiments, (7) and (7,11) by themselves were behaviorally inactive, but in combination attracted numerous male moths. (5,11)-Dimethylheptadecane (5,11) was detected in female SHL pheromone gland extracts, but did not enhance attraction to the binary blend of (7) and (7,11). The sex pheromone of SHL is related to that of congeneric eastern hemlock looper (EHL),Lambdina fiscellaria fiscellaria (Guen.) [(5,11) and 2,5-dimethylheptadecane (2,5)] and western hemlock looper (WHL),L.f. lugubrosa (Hulst) [(5,11), (2,5) and (7)]. Specificity of the pheromonal blend, spatial separation of coseasonal EHL and WHL, and temporal separation of sympatric EHL and SHL contribute to reproductive isolation.

Identification of a pheromone component and a critical synergist for the invasive beetle callidiellum rufipenne (coleoptera: Cerambycidae)

Abstract The invasive Asian cerambycid beetle Callidiellum rufipenne (Motschulsky), informally known as the Japanese cedar longhorned beetle, was first detected in North America in North Carolina in 1997. The beetle has since been detected in neighboring states and is expected to further expand its range. However, delineating the current distribution of C. rufipenne has been hindered by the lack of efficient sampling methods. Here, we present the results of research on the chemistry of volatile pheromones of C. rufipenne. Analyses of headspace odors revealed that males produce (R)-3-hydroxyhexan-2-one, with lesser amounts of (S)-3-hydroxyhexan-2-one, and (R)- and (S)-2-hydroxyhexan-3-one. In field bioassays conducted over several years in Connecticut, where populations of the beetle were well established, no reconstructed blend of these compounds was significantly attractive to beetles of either sex. However, during field trials in Japan that targeted another species, we discovered that adult male and female C. rufipenne were attracted to a blend of racemic 3-hydroxyhexan-2-one and a novel natural product, 1-(1H-pyrrol-2-yl)-1,2-propanedione. Attraction to (R)-3-hydroxyhexan-2-one and the pyrrole subsequently was confirmed in field trials in Connecticut. Although it is unclear why the pyrrole acts as a synergist for a species that apparently does not produce it, the serendipitous discovery that adult C. rufipenne are attracted by the blend of ketone and pyrrole provides a badly needed method for monitoring its ongoing range expansion within North America, and for detecting new introductions in other parts of the world.

DOES PHEROMONE BIOLOGY OF Lambdina athasaria AND L. pellucidaria CONTRIBUTE TO THEIR REPRODUCTIVE ISOLATION

Recently, 7-methylheptadecane and 7,11-dimethylheptadecane have been reported as sex pheromone components of both spring hemlock looper (SHL), Lambdina athasaria, and pitch pine looper (PPL), Lambdina pellucidaria. Our objective was to test the hypothesis that SHL and PPL are reproductively isolated, in part, through species specificity in: (1) absolute configuration of pheromone components, (2) diel periodicity of pheromonal communication, and/or (3) seasonal flight period. In coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses of stereoselectively synthesized (7S)and (7R)-7-methylheptadecane [7S; 7R] as well as (7S,11S)-, (7R,11R)-, and (meso-7,11)-7,11-dimethylheptadecane [7S,11S; 7R,11R; meso-7,11], only 7S and meso-7,11 elicited responses by male SHL and PPL antennae. In field experiments, male SHL and PPL were attracted only to lures containing 7S plus meso-7,11. In hourly recordings of trap-captured males, SHL and PPL in their respective habitats were trapped between 24:00 and 03:00 hr. Capture of both SHL and PPL in pheromone-baited traps throughout June indicated overlapping seasonal flight periods. These findings of identical absolute configuration of pheromoal components, diel periodicity of pheromonal communication, and overlap of seasonal flight periods support synonymy of SHL and PPL. Finite taxonomic classification of PPL and SHL must await careful assessment of further criteria, such as morphometrics, molecular comparisons and ecological analyses.

Sex pheromone components of the apple leafminer, Lyonetia prunifoliella

Three methylated hydrocarbons, 10,14-dimethyloctadec-1-ene (10Me14Me-1-ene-18Hy = 5Me9Me-17-ene-18Hy), 5,9-dimethyloctadecane (5Me9Me-18Hy), and 5,9-dimethylheptadecane (5Me9Me-17Hy), are synergistic sex pheromone components of the leafminer Lyonetia prunifoliella. Compounds extracted from female pheromone glands were identified by coupled gas chromatographic–electroantennographic detection (GC-EAD), and one compound, 10Me14Me-1-ene-18Hy, also by coupled GC–mass spectrometry. In field trapping experiments, 10Me14Me-1-ene-18Hy, 5Me9Me-18Hy, and 5Me9Me-17Hy singly were unattractive to males but in ternary combination attracted numerous male moths. Attractiveness of the three-component blend significantly exceeded that of two-component blends. No attraction of males to pheromone lures without 10Me14Me-1-ene-18Hy indicates that this compound is essential for pheromone communication of L. prunifoliella. Common C-5 and C-9 methyl branches in lyonetiid pheromone hydrocarbons suggest a common biosynthetic pathway; the presence of 5Me9Me-17Hy and 5Me9Me-18Hy in pheromone blends of L. prunifoliella and Leucoptera malifoliella provides evidence for phylogeny of lyonetiid chemical communication. Determination of the stereoisomeric composition is required to completely describe the pheromone blend of L. prunifoliella and to support the hypothesis of phylogenetically related sex pheromones.

Distribution and Hosts of Callidiellum rufipenne (Coleoptera: Cerambycidae), an Asian Cedar Borer Established in the Eastern United States

Abstract The distribution and hosts of the exotic cedar-boring beetle, Callidiellum rufipenne (Motschulsky) (Coleoptera: Cerambycidae), were determined in five northeastern U.S. states by capturing adults on cedar trap logs and by rearing adults from various conifers. This beetle was detected in the coastal states of Massachusetts, Rhode Island, Connecticut, New York, and New Jersey. In these states, adults emerged from the live or dead wood of four genera and eight species of Cupressaceae; species of Pinaceae were not hosts. Through its entire range, C. rufipenne is reported to infest at least 14 species of Cupressaceae, four species of Pinaceae, and one species of Taxaceae; but, records of Pinaceae and possibly Taxaceae are suspect. Based on the number of adults that emerged from coniferous poles in a five-way choice test in the field, the infestation level was significantly greater in Chamaecyparis thyoides (L.) Britton, Sterns, and Poggenburg and Juniperus virginiana L. than in Pinus rigida Miller, Pinus strobus L., and Tsuga canadensis (L.) Carrière (last three species uninfested). In a second test of host preference in the wild, beetles infested four cupressaceous species, but not Abies balsamea (L.) Miller, Picea rubens Sargent, Pinus rigida, P. strobus, and Ts. canadensis in the Pinaceae. Infestation level was highest in Ch. thyoides, followed in decreasing order by Juniperus communis L., Thuja occidentalis L., and J. virginiana. In a comparison of live and dead J. virginiana, beetles developed to adults only in dead trees (36 beetles per tree). When trunk sections of Th. occidentalis with and without bark were offered to females in cages, beetles of the next generation emerged exclusively from wood with bark. In the Northeast, only species of Cupressaceae apparently are suitable hosts for C. rufipenne. Infestation of these species may be prevented or reduced by proper care of live plants and by debarking trees after harvesting.

Exotic Lepidopteran Leafminers in North American Apple Orchards: Rise to Prominence, Management, and Future Threats

The European tentiform leafminers, Phyllonorycter blancardella (Fabricius) and P. mespilella (Hübner) (Lepidoptera: Gracillariidae), have infested apple, Malus domestica Borkhausen, in North America for at least 60–70 years. Unreliable taxonomic methods and lack of voucher specimens, however, have contributed to poor understanding of precisely when, where, and how these leafminers were introduced. Tentiform leafminers developed into significant foliar pests at about the time when adult resistance to broad-spectrum insecticides was detected in the 1970s and 1980s. At present, growers manage leafminers with insecticides and, to a lesser extent, with biological control. Most management programs for orchard pests rely on insecticides that are highly toxic to parasitic wasps, which hampers biological control. New techniques promoted in the context of integrated pest management (IPM) may improve biological control by reducing insecticidal use, but their adoption will depend on cost, labor, need to control other pests, and demands of the marketplace. Management programs must be flexible enough to accommodate changes in the species composition of leafminers and their parasitoids. Procedures to exclude pests may slow the rate of new introductions of leafminers and other pests, but they will not entirely protect the North American apple industry. Once new apple pests reach North America, they face few obstacles to further dispersal. The abundance of potential host plants, the lack of rigorous inspections, and new retail practices may facilitate the dispersal of exotic pests.

Sex Pheromone Components of Pitch Pine Looper, Lambdina pellucidaria

Two methylated hydrocarbons, 7-methylheptadecane (7) and 7,11-dimethylheptadecane (7,11), are sex pheromone components of female pitch pine looper (PPL), Lambdina pellucidaria. Compounds extracted from the pheromone glands of female moths were identified by coupled gas chromatographic–electroantennographic detection (GC-EAD) and coupled GC–mass spectrometry (GC-MS) in selected ion monitoring mode. In field-trapping experiments, 7 and 7,11 in combination, but not singly, attracted numerous male moths. 5,11-Dimethylheptadecane (5,11) was detected by GC-EAD in female PPL pheromone gland extract, but did not significantly increase attraction of PPL males to 7 plus 7,11. Although 7 was > 10 times more abundant than 7,11 in pheromone gland extracts, traps baited with synthetic 7 plus 7,11 at a blend ratio of 1:1, rather than 1:0.1 or 1:0.01, captured the most PPL males. The chemical communication of PPL and spring hemlock looper (SHL), Lambdina athasaria, is strikingly similar. Both species employ 7 plus 7,11 as sex pheromone. Restriction of SHL to forests with eastern hemlock or balsam fir and PPL to forests with pitch or other hard pines contributes to their reproductive isolation. PPL and SHL may also use different optical isomers of enantiomeric 7 and stereoisomeric 7,11 to maintain specificity of their chemical communication.

Emergence, Trapping, and Seasonal Abundance of Adult Cerambycidae (Coleoptera) Associated with Cupressaceae in Connecticut

Abstract Emergence, attraction to traps, and seasonal abundance of cerambycids (Coleoptera) whose larvae injure Cupressaceae were studied under natural conditions in southern Connecticut between 1999 and 2005. Adults of the Asian cerambycid Callidiellum rufipenne (Motschulsky) emerged from trunk sections of Thuja occidentalis L. between late March and mid-May. In contrast, the native Atimia confusa confusa (Say) emerged from trunk sections of Juniperus virginiana L. between late August and mid-October. Emerged adults of both cerambycids had a 1:1 sex ratio, and the emergence of Callidiellum rufipenne showed protandry. In a comparison of four trapping methods, sticky bands stapled to trap logs and dead trees of J. virginiana had the highest density of adults of A. confusa confusa and Callidiellum rufipenne. Based on adults trapped on sticky bands on trap logs, dead trees, or girdled trees of J. virginiana or T. occidentalis at different locations, Callidiellum rufipenne was active on hosts for 5–8 wk between April and June; Semanotus ligneus ligneus (Say) for 4 wk in April; Callidium frigidum Casey for 5 wk between early May and early June; and A. confusa confusa for ≈12 wk between April and early July and again for 2–5 wk between September and late October. Catches of A. confusa confusa were significantly female-biased. Number of beetles captured usually was not correlated with the size of the sticky band on trap logs, cut trees, or girdled trees. This is the first quantitative study on emergence, trapping, and seasonal abundance of cerambycids associated with Cupressaceae in northeastern North America.

Sex Pheromone of Apple Blotch Leafminer, Phyllonorycter crataegella, and Its Effect on P. mespilella Pheromone Communication

Abstract(Z)-10,(Z)-12-Tetradecadienyl acetate (Z10,Z12–14:OAc) and (E)-10,(E)-12-tetradecadienyl acetate (E10,E12–14:OAc) are sex pheromone components of the apple blotch leafminer (ABLM), Phyllonorycter crataegella. Compounds extracted from female pheromone glands were identified by coupled gas chromatographic–electroantennographic detection (GC-EAD) analyses, retention index calculations of EAD-active compounds, and by comparative GC-EAD analyses of female ABLM-produced and authentic (synthetic) compounds. In field experiments in apple Malus domestica orchards in Connecticut, Z10,Z12–14:OAc alone attracted ABLM males. Addition of E10,E12–14:OAc to Z10,Z12–14:OAc at 0.1:10 or 1:10 ratios enhanced attractiveness of the lure. Geometrical isomers Z10,E12- or E10,Z12–14:OAc at equivalent ratios were behaviorally benign and slightly inhibitory, respectively. In field experiments in British Columbia, Z10,Z12–14:OAc plus E10,E12–14:OAc did not attract Phyllonorycter moths, supporting the contention that ABLM is not present in the fruit growing regions of British Columbia. Z10,Z12–14:OAc added to P. mespilella pheromone, (E)-4,(E)-10-dodecadienyl acetate, strongly inhibited response by P. mespilella males. Recognition of the ABLM pheromone blend by allopatric P. mespilella males suggests a phylogenetic relationship and previous sympatry of these two Phyllonorycter spp. If pheromonal attraction of ABLM males were reciprocally inhibited by P. mespilella pheromone, a generic Phyllonorycter pheromone blend could be tested for pheromone-based mating disruption of the apple leaf-mining Phyllonorycter guild in North America.

Distribution, Hosts, Abundance, and Seasonal Flight Activity of the Exotic Leafroller, Archips fuscocupreanus Walsingham (Lepidoptera: Tortricidae), in the Northeastern United States

Abstract Archips fuscocupreanus Walsingham (Lepidoptera: Tortricidae) is an eastern Asian leafroller that recently was detected in Connecticut and Massachusetts. Based on males captured in pheromone traps between 1998 and 2000, A. fuscocupreanus inhabits five northeastern coastal states between Massachusetts and New Jersey. In Massachusetts, Connecticut, and New York, larvae had a broad host range, feeding on 87 plants in 15 families. Fifty-nine hosts (67.8%) were in the Rosaceae, the plant family that includes economically important pome and stone fruits. In outdoor cages, adult females laid a similar number of egg masses on five different species of potted fruit trees that are grown widely. At The Arnold Arboretum in Massachusetts, larval abundance was highest on Ilex verticillata (L.) Gray (3.4 larvae per plant) although it was statistically similar to that on four rosaceous species (1.0–1.8 larvae per plant), and significantly higher than that on another 12 rosaceous trees (0–0.5 larvae per plant). In an insecticide-free apple orchard at Hamden, Connecticut, males flew for 4–5 wk between mid-June and mid-July 2000–2001. Based on its broad host range in the United States and on its development of insecticide resistance in Japan, A. fuscocupreanus poses a threat to the fruit and nursery industries in North America.