Response of Invasive Longhorn Beetles (Coleoptera: Lamiinae) to Known Cerambycid Aggregation-Sex Pheromones in the Puna District of Hawaii Island

The Queensland longhorn borer (QLB; Acalolepta aesthetica [Olliff 1890]; Coleoptera: Cerambycidae: Lamiinae: Monochamini) and plumeria long- horn borer (PLB; Lagocheirus obsoletus [Thomson 1778] = Lagocheirus undatus [Voet 1778]; Coleoptera: Cerambycidae: Lamiinae: Acanthocini) are invasive longhorn beetle species that have become established on the island of Hawaii. Both QLB and PLB are polyphagous. Known hosts of QLB include cacao, citrus, kukui, and breadfruit in Hawaii, and QLB are known to attack live, healthy trees. Currently the beetle occurs in the Puna district of the island, but its range is expanding. PLB is a pest of plumeria and other ornamental plants throughout the state of Hawaii and elsewhere. As a first step towards developing a monitoring tool for these invasive beetles, we tested four known aggregation-sex pheromones of cerambycids in this subfamily—monochamol, fuscumol acetate, fuscumol, and geranylacetone—that have proven effective for attracting more than 30 lamiine species in different areas of the world. When tested in panel traps, these compounds individually and in a blend attracted 9 QLB total, which was not significantly different than the 5 QLB captured in solvent control traps. In contrast, traps baited with one of the tested compounds, fuscumol acetate, captured significantly more PLB than solvent blank control traps. We discuss future research directions for developing attractants using chemical ecology approaches to monitor QLB and PLB

Effects of Ultraviolet Light and Pheromone Release Rate in Trapping Coconut Rhinoceros Beetles, Oryctes rhinoceros (Coleoptera: Scarabaeidae), on Guam

Coconut rhinoceros beetle (CRB), Oryctes rhinoceros L., is a serious pest of coconut and oil palms throughout Southeast Asia and the Pacific. CRB was found on Guam in 2007 and, despite suppression efforts, has subsequently spread across the island. The CRB population on Guam is genetically different from other populations in Asia and the Pacific, and is considered a new invasive biotype (termed CRB-G). CRB-G is apparently resistant to Oryctes rhinoceros nudivirus, the preferred biocontrol agent for this pest. CRB populations are typically controlled with a combination of biocontrol, pheromone traps, and breeding site removal. A field trial was performed at six locations on Guam to test potential improvements to standard CRB pheromone trapping with oryctalure (ethyl 4-methyloctanoate). Two modifications were tested, 1) addition of ultraviolet light emitting diodes (UV LEDs), and 2) reduction of pheromone release rate. Addition of UV LED light sources to pheromone traps significantly increased trap catch by 2.85 times. Reduction in oryctalure release rate by up to an order of magnitude did not significantly change CRB capture rate. Further, when linear regression analyses of CRB trap capture rate as a function of pheromone release rate were conducted for traps with and without UV LEDs separately, only a very weak relationship between trap capture and oryctalure release rate was observed and only when a UV LED was present. Results suggest that addition of UV LED light sources to pheromone traps could improve detection trapping of CRB and that reduction of pheromone release rate could extend service life of lures without changing capture rate

Hydrolysis of Queensland fruit fly, Bactrocera tryoni (Froggatt), attractants : kinetics and implications for biological activity

Queensland fruit fly (Q-fly), Bactrocera tryoni (Froggatt), is a major insect pest of horticultural crops in Australia. Cuelure is the most commonly used attractant for monitoring as well as for management of Q-fly populations through the male annihilation technique and mass trapping. There has been some concern that cuelure is susceptible to hydrolysis, which would limit its usefulness under conditions of high humidity and give rise to inconsistent fly population monitoring. To give some insight into the hydrolysis of cuelure and two closely related compounds, melolure and a newly developed lure, 4-(4-(2,2,2-trifluoroacetoxy)phenyl)-2-butanone (RKTA), the kinetics of hydrolysis of these compounds were quantitatively investigated by gas chromatography-flame ionization detection. From the experimental data, we found the hydrolysis half-lives of cuelure, melolure, and RKTA, at a water concentration of 25 mol L⁻¹, to be ~20 days, 22 h, and 1.2 min respectively. When extrapolated to a water concentration of 1.3 mmol L⁻¹, corresponding to atmospheric conditions of 100% relative humidity at 25℃, the half-lives are ~1660, ~51, and ~1.4 years respectively.5 page(s

Cucumber Lure Trapping of Zeugodacus cucurbitae (Diptera: Tephritidae) in Hawaii and Taiwan: Longevity and Nontargets Captures

The melon fly, Zeugodacus cucurbitae (Coquillett), is a serious pest of tropical horticulture, causing damage to cucurbits, tree fruits, and fruiting vegetables. Melon flies are especially attractive to freshly sliced cucumber, and this has led to the identification of a nine-compound kairomone lure that can be used to trap both female and male flies. In this study, a seven-compound lure, containing (Z)-6-nonenal, (Z)-6-nonen-1-ol, 1-octen-3-ol, (E,Z)-2,6nonadienal, (E)-2-nonenal, hexanal, and 1-hexanol, was formulated into PVC plugs (100 or 300mg/plug) for field testing in wet traps. In Hawaii, 100mg of the seven-compound cucumber lure, loaded in either plugs or glass capillaries, attracted more flies than traps containing Solulys protein over a 9-wk period. However, both cucumber lure formulations showed marked declines in the number of flies trapped after 3 wk. Similar results were obtained during a 6-wk field trial using 100mg cucumber lure plugs in Taiwan. Increasing the cucumber lure loading rate to 300mg/ lure increased the effective trapping life of the attractant during a second 9-wk field trial conducted in Hawaii. The synthetic cucumber lure showed female-biased sex ratios in trap captures in the Taiwanese and second Hawaiian field trials. Protein lures captures were female-biased in all three field trials. Wet traps in Hawaii containing the cucumber lure were found to capture 25-30 nontarget insects/trap/week, less than half that captured with Solulys. Captured nontarget insects represented 37 families in 10 orders. The most common families caught were Ceratopogonidae (similar to 9 flies/trap) and Gryllidae (similar to 7 crickets/trap)

Electroantennogram responses of six Bactrocera and Zeugodacus species to raspberry ketone analogues

Environmental context. Queensland fruit fly is a major pest of fruits and vegetables in eastern Australia, sometimes causing complete loss of unprotected crops. Odours that attract fruit flies can help control these pests and this study investigated how six fruit fly species smell these chemicals. The strength of fly responses to tested odours gives insight into the way flies smell and provides information for making better attractants, potentially reducing insecticide use.. The Queensland fruit fly (Bactrocera tryoni, Q-fly) is a major horticultural pest in eastern Australia. The deployment of male lures comprises an important component of several detection and control strategies for this pest. A novel fluorinated analogue of raspberry ketone (RK), raspberry ketone trifluoroacetate (RKTA), has been developed with the aim of further improving Q-fly control. RKTA elicited strong electroantennogram (EAG) responses from Q-flies whereas cuelure (CL) and melolure (ML) responses were not significantly greater than a negative control. Further experimentation showed that RKTA also elicited EAG response from five other fruit fly species, included flies known to be strongly attracted to CL (B. neohumeralis, B. kraussi and B. frauenfeldi), weakly attracted to CL (B. jarvisi), or non-responsive to CL (Zeugodacus cucumis), whereas seven other compounds, RK, CL, ML, raspberry ketone difluoroacetate, raspberry ketone monofluoroacetate, anisyl acetone and trimethylsilyl raspberry ketone, elicited only weak responses comparable with a negative control. However, fly EAG responses to RKTA are likely due at least in part to trifluoroethanoic acid, which is a hydrolysis product of RKTA and elicited strong EAG responses from all six species when tested alone. Furthermore, whereas ethanoic acid, methanoic acid and trifluoroethanoic acid all elicited strong EAG responses in Q-flies, the only corresponding RK ester to elicit an EAG response was RKTA, suggesting that RKTA hydrolyses quickly, whereas CL and ML do not. This is in contrast to the idea that CL readily hydrolyses on contact with atmospheric moisture, an assertion that has been made in the literature repeatedly

Tagged melon fly, <i>Zeugodacus cucurbitae</i>, release points (black center with yellow or white border) and landing points (yellow or white dots) at Lokahi Park, Hilo, HI.

Yellow and white arrows indicate the mean wind direction during fly releases. Source: U.S. Geological Survey, 2011, USGS High Resolution State Orthoimagery for the East Side of Hawaii Island: 05QKB820780_200912_0x5000m_CL_1: U.S. Geological Survey.</p

Melon fly, <i>Zeugodacus cucurbitae</i>, flight step-distances for experiments 4–5 with best fit lines.

For experiment 4, step-distances of less than 1 m were removed. (TIF)</p

Raspberry ketone analogs : vapour pressure measurements and attractiveness to Queensland fruit fly, Bactrocera tryoni (Froggatt) (Diptera : Tephritidae)

The Queensland fruit fly, Bactrocera tryoni (Froggatt) (Q-fly), is a major horticultural pest in Eastern Australia. Effective monitoring, male annihilation technique (MAT) and mass trapping (MT) are all important for control and require strong lures to attract flies to traps or toxicants. Lure strength is thought to be related in part to volatility, but little vapour pressure data are available for most Q-fly lures. Raspberry ketone (4-(4-hydroxyphenyl)-2-butanone) and analogs that had esters (acetyl, difluoroacetyl, trifluoroacetyl, formyl, propionyl) and ethers (methyl ether, trimethylsilyl ether) in replacement of the phenolic group, and in one case also had modification of the 2-butanone side chain, were measured for their vapour pressures by differential scanning calorimetry (DSC), and their attractiveness to Q-fly was assessed in small cage environmentally controlled laboratory bioassays. Maximum response of one category of compounds, containing both 2-butanone side chain and ester group was found to be higher than that of the other group of compounds, of which either of 2-butanone or ester functionality was modified. However, linear relationship between vapour pressure and maximum response was not significant. The results of this study indicate that, while volatility may be a factor in lure effectiveness, molecular structure is the dominating factor for the series of molecules investigated.16 page(s

Fig 3 -

Combined pseudo-turning angles of HR tagged Zeugodacus cucurbitae for experiment 2 (A) and experiment 3 (B). A turning angle of zero indicated that a fly flew in the same direction as the directly previous flight. Combined turning angles were non-random by both Rayleigh and Hermans-Rasson tests, showed no right-left bias, but indicate a pronounced bias towards moving within 90° left or right of the directly previous flight.</p