Comparing Deliveries of Sterile Codling Moth (Lepidoptera: Tortricidae) by Two Types of Unmanned Aerial Systems and from the Ground

New Zealand apple exports must meet strict phytosanitary measures to eliminate codling moth (Cydia pomonella Linnaeus) (Lepidoptera: Tortricidae) larval infestation. This study was part of a program attempting the localized eradication of codling moth within an isolated cluster of seven orchards (391 ha). A conventional management program of insecticide sprays and pheromone mating disruption was supplemented with weekly releases of sterile moths for 1-6 yr. Our objective was to compare the recapture rate of sterile moths following their release by four methods, and the efficiency of each system. The methods were the following: a fixed-wing unmanned plane flying ~40-45 m high at 70 km/h, an unmanned hexacopter travelling 20 m high at 25 km/h, and manually from the ground via bicycles or motor vehicles. The different release methods were used in different years or weeks. Sterile male moths were recaptured in grids of pheromone traps positioned throughout each orchard. The highest recapture rate followed delivery by hexacopter, then bicycle, vehicle, and plane. There was a 17-fold difference in catches between releases by hexacopter and plane, and sixfold between vehicle and plane in the same season. Bicycle delivery had a 3.5-fold higher recapture rate than the plane in different years. The wind-borne horizontal drift of moths was investigated as a possible explanation for the disparity of recaptures between the two aircraft delivery systems. The methods in ascending order of time per hectare for delivery were the following: plane and vehicle, hexacopter, then bicycle. The advantages and disadvantages of each moth delivery method are discussed.

Irradiation biology of male brown marmorated stink bugs: is there scope for the sterile insect technique?

PURPOSE

Brown marmorated stink bugs, Halyomorpha halys Stål (Hemiptera: Pentatomidae), are regularly intercepted, but there are few eradication tools. Currently, no sterile insect technique program exists for Hemiptera.

MATERIALS AND METHODS

Adult males were irradiated at 4-60 Gy, mated and their progeny reared for two generations, with mortality assessed at F₁ egg, F₁ adult and F₂ egg stages.

RESULTS

The F₁ eggs showed a dose response to irradiation between 4 and 36 Gy, with 97% sterility at 16 Gy, and higher doses producing complete egg mortality. Only rare F₁ survivors had progeny, but the F₂ generation showed identical responses between maternal and paternal lines; most egg batches showed either very low or very high mortality. Irradiation with 16 Gy resulted in 98.5% sterility, cumulative over F₁ and F₂.

CONCLUSIONS

Lack of a dose response at the F₂ generation precludes the use of irradiation-induced inherited sterility. The conventional sterile insect technique appears possible by irradiation of males from ∼12 to 16 Gy. The effect of radiation dose on females is not known, thus we cannot conclude whether bi-sex release is feasible so for now the release of males only is recommended. More work is needed on the competitive fitness of irradiated males, and logistics such as mass rearing or field collection, in order to determine the feasibility of the approach.

Caterpillar-Induced Plant Volatiles Attract Adult Tortricidae

Binary and ternary combinations of volatile organic compounds identified earlier from caterpillar-infested apple foliage caught more than one thousand individuals of both sexes of several adult tortricid leafroller species in several days of trials conducted in apple orchards in southern British Columbia. A series of combinations with phenylacetonitrile, benzyl alcohol, and/or 2-phenylethanol and acetic acid enabled substantial catches of both sexes of eye-spotted budmoth, Spilonota ocellana, oblique-banded leafroller, Choristoneura rosaceana and three-lined leafroller, Pandemis limitata. These findings suggest that new monitoring aides can be developed to seasonally track populations, enabling practical applications in surveillance of female leafroller populations for the first time. It may also be possible to develop suppression tools based on combinations of kairomone compounds originally identified from leafroller larval-damaged apple trees, given the level of attraction. The discovery of these adult tortricid attractants (aromatic compounds plus acetic acid) raises new ecological questions about evolved direct plant defences against herbivores. Larval feeding-induced attraction of adult herbivores produces signals that are potentially harmful to the plant by increasing herbivory in the same family and probably feeding guild, but evidence for effects on plant fitness is needed.

Morganella morganii bacteria produces phenol as the sex pheromone of the New Zealand grass grub from tyrosine in the colleterial gland

Costelytra zealandica (Coleoptera: Scarabeidae) is a univoltine endemic species that has colonised and become a major pest of introduced clover and ryegrass pastures that form about half of the land area of New Zealand. Female beetles were previously shown to use phenol as their sex pheromone produced by symbiotic bacteria in the accessory or colleterial gland. In this study, production of phenol was confirmed from the female beetles, while bacteria were isolated from the gland and tested for attractiveness towards grass grub males in traps in the field. The phenol-producing bacterial taxon was identified by partial sequencing of the 16SrRNA gene, as Morganella morganii. We then tested the hypothesis that the phenol sex pheromone is biosynthesized from the amino acid tyrosine by the bacteria. This was shown to be correct, by addition of isotopically labelled tyrosine ((13)C) to the bacterial broth, followed by detection of the labelled phenol by SPME-GCMS. Elucidation of this pathway provides specific evidence how the phenol is produced as an insect sex pheromone by a mutualistic bacteria.

Combining odours isolated from phylogenetically diverse sources yields a better lure for yellow jackets

BACKGROUND

Invasive wasps have major impacts on bird populations and other biodiversity in New Zealand beech forests, and new solutions are needed for their management. Baits were combined from four phylogenetically diverse sources (protein and carbohydrate) to improve attraction to a level that could be used as the basis for more powerful attract-and-kill systems. Many compounds from honey, scale insect honeydew, fermenting brown sugar and green-lipped mussels were highly attractive and, when combined, outcompeted known attractants.

RESULTS

The equivolumetric lure (equal parts of 3-methylbut-1-yl acetate, 2-ethyl-1-butanol, 1-octen-3-ol, 3-octanone, methyl phenylacetate and heptyl butanoate), gave a 5-10-fold improvement over the known attractant, octyl butanoate, and other previously patented lures. An economically optimised lure of the same compounds, but in a ratio of 2:1.6:1:1:2:2.4, was equally attractive as the equal-ratio lure. Pilot mass trapping attempts with this latter lure revealed that >400 wasps trap(-1) day(-1) could be caught at the peak of the season.

CONCLUSION

The new lures are comprised of compounds from animals, plants and fungi, thus targeting the omnivorous behaviour of these wasps.

Communication disruption of guava moth (Coscinoptycha improbana) using a pheromone analog based on chain length

The guava moth, Coscinoptycha improbana, an Australian species that infests fruit crops in commercial and home orchards, was first detected in New Zealand in 1997. A four-component pheromone blend was identified but is not yet commercially available. Using single sensillum recordings from male antennae, we established that the same olfactory receptor neurons responded to two guava moth sex pheromone components, (Z)-11-octadecen-8-one and (Z)-12-nonadecen-9-one, and to a chain length analog, (Z)-13-eicosen-10-one, the sex pheromone of the related peach fruit moth, Carposina sasakii. We then field tested whether this non-specificity of the olfactory neurons might enable disruption of sexual communication by the commercially available analog, using male catch to synthetic lures in traps in single-tree, nine-tree and 2-ha plots. A disruptive pheromone analog, based on chain length, is reported for the first time. Trap catches for guava moth were disrupted by three polyethylene tubing dispensers releasing the analog in single-tree plots (86% disruption of control catches) and in a plots of nine trees (99% disruption). Where peach fruit moth pheromone dispensers were deployed at a density of 1000/ha in two 2-ha areas, pheromone traps for guava moth were completely disrupted for an extended period (up to 470 days in peri-urban gardens in Mangonui and 422 days in macadamia nut orchards in Kerikeri). In contrast, traps in untreated areas over 100 m away caught 302.8 ± 128.1 moths/trap in Mangonui and 327.5 ± 78.5 moths/ trap in Kerikeri. The longer chain length in the pheromone analog has greater longevity than the natural pheromone due to its lower volatility. Chain length analogs may warrant further investigation for mating disruption in Lepidoptera, and screening using single-sensillum recording is recommended.

Improving the efficiency of lepidopteran pest detection and surveillance: constraints and opportunities for multiple-species trapping

Surveillance using attractants for invasive species can allow early detection of new incursions and provide decision support to response programs. Simultaneous trapping for multiple species, by baiting traps with several lures, is expected to increase the number of species that can be targeted in surveillance programs and improve the cost-effectiveness without affecting surveillance coverage. We tested this hypothesis by choosing four potential forest and urban lepidopteran pest species that are present in Europe but not yet in New Zealand and many other countries. We deployed traps in central and southern Europe with single lures or all possible species combinations (up to four lures per trap). There was only limited interference, apparently due to trap saturation, but no evidence for interspecific repellency among lures for gypsy moth, Lymantria dispar, fall webworm, Hyphantria cunea, pine processionary moth, Thaumetopoea pityocampa, and pine shoot moth, Rhyacionia buoliana. To assess what factors may be important in species compatibility/suitability for multiple-species trapping, we combined our results with those of previous studies conducted by the United States Department of Agriculture. For 75 combinations of pheromones, tested singly or in combination, 19 % showed no effect on trap catch for any of the species tested. In the other cases, either one or both species showed a reduction in trap catch. However, few lure combinations caused complete or nearly complete suppression. For most combinations, catches were still sufficiently high for detection purposes. Species from the same superfamily exhibited more interference than more distantly related species. Together, these results suggest that there are opportunities to improve the range of exotic pests under surveillance, at little additional cost, by multiple-species trapping for which compatibility has been demonstrated.

Volatiles from apple trees infested with light brown apple moth larvae attract the parasitoid Dolichogenidia tasmanica

The volatile compounds emitted from uninfested apple seedlings, cv. Royal Gala, and apple seedlings infested with generalist herbivore Epiphyas postvittana larvae were sampled using headspace collection and analyzed by gas chromatography-mass spectrometry. Nine additional compounds were only detected in infested apple seedlings [including benzyl alcohol, (E)-β-ocimene, benzyl cyanide, indole, (E)-nerolidol, and four unidentified compounds]. Infested apple seedlings produced larger amounts of (Z)-3-hexenyl acetate, linalool, 4,8-dimethyl-1,3(E),7-nonatriene, methyl salicylate, β-caryophyllene, germacrene D, (E,E)-α-farnesene, and (Z)-3-hexenyl benzoate than uninfested plants. Female parasitoids flew exclusively upwind to infested and not to uninfested apple seedlings in wind tunnel choice tests and preferred infested leaflets in still air, even after the removal of larvae. The attraction of a parasitoid to infested apple seedlings in the laboratory and in the field to apple and many other plants in at least six families supports considerable generality of the tritrophic signaling process.

Worldwide host plants of the highly polyphagous, invasive Epiphyas postvittana (Lepidoptera: Tortricidae)

The light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is a highly successful biological invader. It was accidentally introduced to several countries including New Zealand, Hawaii, England, and California. Light brown apple moth attacks a wide range of crop plants and other woody and herbaceous plants, but a more comprehensive analysis of its host range is needed for risk assessments, to evaluate the likely economic and environmental impacts, and to enable targeting of particular plant species for detection surveys and treatments. We reviewed and synthesized the host range and host selection behavior of light brown apple moth by using information from Australia and invaded countries. The host range of light brown apple moth is determined by the behavior of both adult females and larvae. Females use visual, chemical and physical cues to choose host plants. Larvae are capable of limited active dispersal by walking and longer range dispersal by ballooning on silken strands; therefore, larvae also may need to select host plants. We review larval performance indicators across a range of plants. Based on our review, there are at least 545 plant species in 363 genera from 121 families that have been reported as hosts of light brown apple moth. Some plants were reported only once and need verification. Nevertheless, many host plant species and their wide phylogenetic range (from ferns to higher dicotyledons) indicates that light brown apple moth is one of the most polyphagous insects known. This information and our categorization of frequency of host use are valuable for incursion response and pest management activities.

Invasion biology, ecology, and management of the light brown apple moth (Tortricidae)

Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), the light brown apple moth (LBAM), is an important leafroller pest with an exceptionally wide host range that includes many horticultural crops and other woody and herbaceous plants. LBAM is native to southeastern Australia but has invaded Western Australia, New Zealand, Hawaii, much of England, and in 2007, it was confirmed as established in California. The discovery of this pest in California has led to a major detection and regulatory effort because of concerns about economic and environmental impacts. Its recent discovery in Sweden is also of note. LBAM has often been intercepted on imports of fruit and other plant parts, and it has the potential to become a successful invader in temperate and subtropical regions worldwide. The importance of the insect has prompted development of classical biological control programs together with a wide variety of other management interventions that can be used in integrated pest management or integrated pest eradication.

Potential of "lure and kill" in long-term pest management and eradication of invasive species

"Lure and kill" technology has been used for several decades in pest management and eradication of invasive species. In lure and kill, the insect pest attracted by a semiochemical lure is not "entrapped" at the source of the attractant as in mass trapping, but instead the insect is subjected to a killing agent, which eliminates affected individuals from the population after a short period. In past decades, a growing scientific literature has been published on this concept. This article provides the first review on the potential of lure and kill in long-term pest management and eradication of invasive species. We present a summary of lure and kill, either when used as a stand-alone control method or in combination with other methods. We discuss its efficacy in comparison with other control methods. Several case studies in which lure and kill has been used with the aims of long-term pest management (e.g., pink bollworm, Egyptian cotton leafworm, codling moth, apple maggot, biting flies, and bark beetles) or the eradication of invasive species (e.g., tephritid fruit flies and boll weevils) are provided. Subsequently, we identify essential knowledge required for successful lure and kill programs that include lure competitiveness with natural odor source; lure density; lure formulation and release rate; pest population density and risk of immigration; and biology and ecology of the target species. The risks associated with lure and kill, especially when used in the eradication programs, are highlighted. We comment on the cost-effectiveness of this technology and its strengths and weaknesses, and list key reasons for success and failure. We conclude that lure and kill can be highly effective in controlling small, low-density, isolated populations, and thus it has the potential to add value to long-term pest management. In the eradication of invasive species, lure and kill offers a major advantage in effectiveness by its being inverse density dependent and it provides some improvements in efficacy over related control methods. However, the inclusion of insecticides or sterilants in lure and kill formulations presents a major obstacle to public acceptance.

Floral scent of Canada thistle and its potential as a generic insect attractant

The flowers of Canada thistle, Cirsium arvense (L.), attract a wide range of insects, including pollinators and herbivorous species. This attraction is primarily mediated by floral odor, which offers potential for developing generic insect attractants based on odor. In this study, we have analyzed the chemical composition of the volatiles produced by Canada thistle flowers. Nineteen floral compounds were identified in the headspace, including phenylacetaldehyde (55%), methyl salicylate (14%), dimethyl salicylate (8%), pyranoid linalool oxide (4.5%), and benzaldehyde (3.5%). Other minor compounds include benzyl alcohol, methylbenzoate, linalool, phenylethyl alcohol, furanoid linalool oxide, p-anisaldehyde, 2,6-dimethyl-1,3,5,7-octatetraene, benzylacetate, benzyl tiglate, (E,E)-alpha-farnesene, benzyl benzoate, isopropyl myristate, and 2-phenylethyl ester benzoic acid. The relative attractiveness of various doses of the main floral volatile compound phenylacetaldehyde (i.e., 10, 100, 200, and 400 mg) was tested for insect attraction. Both the total catch and the biodiversity of insect species trapped increased as the loading of phenylacetaldehyde increased. Volatiles were chosen from the odors from the flowers of Canada thistle and formulated and tested in the field. An 11-component blend was the most attractive of several floral blends tested. These findings indicate that chemical components of flower odors of Canada thistle can serve as a generic insect attractant for monitoring of invasive pest species.

Floral scent of Canada thistle and its potential as a generic insect attractant

The flowers of Canada thistle, Cirsium arvense (L.), attract a wide range of insects, including pollinators and herbivorous species. This attraction is primarily mediated by floral odor, which offers potential for developing generic insect attractants based on odor. In this study, we have analyzed the chemical composition of the volatiles produced by Canada thistle flowers. Nineteen floral compounds were identified in the headspace, including phenylacetaldehyde (55%), methyl salicylate (14%), dimethyl salicylate (8%), pyranoid linalool oxide (4.5%), and benzaldehyde (3.5%). Other minor compounds include benzyl alcohol, methylbenzoate, linalool, phenylethyl alcohol, furanoid linalool oxide, p-anisaldehyde, 2,6-dimethyl-1,3,5,7-octatetraene, benzylacetate, benzyl tiglate, (E,E)-alpha-farnesene, benzyl benzoate, isopropyl myristate, and 2-phenylethyl ester benzoic acid. The relative attractiveness of various doses of the main floral volatile compound phenylacetaldehyde (i.e., 10, 100, 200, and 400 mg) was tested for insect attraction. Both the total catch and the biodiversity of insect species trapped increased as the loading of phenylacetaldehyde increased. Volatiles were chosen from the odors from the flowers of Canada thistle and formulated and tested in the field. An 11-component blend was the most attractive of several floral blends tested. These findings indicate that chemical components of flower odors of Canada thistle can serve as a generic insect attractant for monitoring of invasive pest species.

Positive interaction of a feeding attractant and a host kairomone for trapping the codling moth, Cydia pomonella (L.)

Codling moths are attracted to acetic acid and to ethyl-(E,Z)-2,4-decadienoate, the pear ester, when presented individually. The attraction to acetic acid is thought to be a food finding behavior, whereas the pear odorant, ethyl-(E,Z)-2,4-decadienoate, may be a host kairomone. We found, in a flight tunnel study, that more male and female codling moths were captured in traps when the compounds were presented together compared to tested separately. The combination of odorants provides a stronger lure for female codling moths than exists with pear ester alone and increases the potential for using lures in managing this pest of pome fruits and walnuts.

Can ménage-a-trois be used for controlling insects?

We propose a new cross-species disruption approach that might be capable of interrupting mating of one species that uses another insect species as the mercenary agent. We argue that insects treated with a sufficiently powerful attractant for a second species might interfere with mating of one or both species, for example, by leading males astray in pursuit of the false trails created by suitably dosing individuals of the first species. Our reciprocal test systems used (1) methyl eugenol, an attractant for male oriental fruit flies (Bactrocera dorsalis), applied to melon flies (B. cucurbitae) and (2) cuelure, a lure for male melon flies, applied to B. dorsalis. There was no mortality 1 week after either attractant was applied to individual flies at doses up to 100 ng, which was effective in attracting insects in a field cage and in the field. In wind tunnel choice tests, 100 ng of either lure topically applied to tethered flies attracted fruit fly males of the second species, which exhibited prolonged bouts of physically disruptive behaviors including chasing and bumping. In small cages, treatment of males did not reduce mating of either species, with one group of three (ménage) per cage. However, in large field cages with multiple pairs of both species present, there was a significant reduction in the mating of melon flies resulting from methyl eugenol applied to males compared to untreated controls. The treatment of oriental fruit flies with cuelure also reduced their mating to a lesser extent. These results do not yet provide the practical proof of this new concept for pest management, but other model systems may be more appropriate. This work is novel in presenting attractants on a moving target, in this case, another insect species.

Potential of mass trapping for long-term pest management and eradication of invasive species

Semiochemical-based pest management programs comprise three major approaches that are being used to provide environmentally friendly control methods of insect pests: mass trapping, "lure and kill," and mating disruption. In this article, we review the potential of mass trapping in long-term pest management as well as in the eradication of invasive species. We discuss similarities and differences between mass trapping and other two main approaches of semiochemical-based pest management programs. We highlight several study cases where mass trapping has been used either in long-term pest management [e.g., codling moth, Cydia pomonella (L.); pink bollworm, Pectinophora gossypiella (Saunders); bark beetles, palm weevils, corn rootworms (Diabrotica spp.); and fruit flies] or in eradication of invasive species [e.g., gypsy moth, Lymantria dispar (L.); and boll weevil, Anthonomus grandis grandis Boheman). We list the critical issues that affect the efficacy of mass trapping and compare these with previously published models developed to investigate mass trapping efficacy in pest control. We conclude that mass trapping has good potential to suppress or eradicate low-density, isolated pest populations; however, its full potential in pest management has not been adequately realized and therefore encourages further research and development of this technology.

Identification of sex pheromone components of a New Zealand geometrid moth, the common forest looper Pseudocoremia suavis, reveals a possible species complex

Gas chromatography-electroantennographic detection analysis of sex pheromone gland extracts of the common forest looper Pseudocoremia suavis (Lepidoptera: Geometridae), a polyphagous defoliator of introduced Pinaceae and many New Zealand trees, revealed four compounds that elicited antennal responses. The two major active compounds (6Z)-cis-9,10-epoxynonadec-6-ene and (3Z,6Z)-cis-9,10-epoxynonadeca-3,6-diene were identified by comparison with known standards. Of the two minor active compounds, one was tentatively identified as (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene, whereas the other could not be identified because of insufficient amounts in extracts. (6Z)-cis-9,10-Epoxynonadec-6-ene, (3Z,6Z)-cis-9,10-epoxynonadeca-3,6-diene, and (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene were present in P. suavis gland extracts from Eyrewell Forest, a Pinus radiata plantation in the South Island of New Zealand, in a ratio of 35:65:5, respectively. Trapping trials in Eyrewell Forest established that (6Z)-cis-9,10-epoxynonadec-6-ene attracted male P. suavis. However, addition of (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene to the lure at <10% of (6Z)-cis-9,10-epoxynonadec-6-ene reduced capture of male moths, suggesting that one of its enantiomers was acting as a behavioral antagonist. During January-March of 2005, a blend trial involving single, binary, and ternary mixtures of the three components at Eyrewell Forest and at three other sites (two in the South Island and one in the North Island) revealed the existence of a second taxon of P. suavis at the three additional sites that was attracted to lures containing (3Z,6Z)-cis-9,10-epoxynonadeca-3,6-diene, either singly or in binary and ternary mixtures with (6Z)-cis-9,10-epoxynonadec-6-ene and (3Z,6Z)-cis-9,10-epoxyhenicosa-3,6-diene. This second taxon was not attracted to lures loaded solely with (6Z)-cis-9,10-epoxynonadec-6-ene.

(Z)-7-tricosene and monounsaturated ketones as sex pheromone components of the Australian guava moth Coscinoptycha improbana: identification, field trapping, and phenology

Pheromone gland extracts of the Australian guava moth Coscinoptycha improbana (Lepidoptera: Carposinidae), contained four compounds that elicited responses from male moth antennae in gas chromatography-electroantennogram detection (GC-EAD) analyses. These were identified by GC-mass spectrometry as (Z)-7-tricosene (Z7-23Hy), (Z)-7-octadecen-11-one (Z7-11-one-18Hy), (Z)-7-nonadecen-11-one (Z7-11-one-19Hy), and (Z)-7-tricosen-11-one (Z7-11-one-23Hy) at a ratio of 65:23.5:1.5:10, respectively. Z7-23Hy, Z7-11-one-18Hy, and Z7-11-one-23Hy have not previously been reported as lepidopteran sex pheromone components. Z7-11-one-18Hy was active as a single component, and was synergized by Z7-11-one-23Hy but not Z7-11-one-19Hy, although the latter compound was weakly attractive as a single component. Addition of Z7-23Hy further increased attraction. The amount of the major pheromone component, Z7-11-one-18Hy in female pheromone gland extracts was estimated to be 16.4 ng/female (N = 8). Phenological data gathered over a 12-mo period in 2002 and 2003 using the binary blend indicated that moths are active throughout the year. The pheromone has already been employed to monitor the spread of C. improbana in New Zealand and detect its presence in Queensland, Australia.

Sex pheromone of the citrus flower moth Prays nephelomima: pheromone identification, field trapping trials, and phenology

Analysis of sex pheromone gland extract of the citrus flower moth, Prays nephelomima (Lepidoptera: Yponomeutidae) by coupled gas chromatography-electroantennogram detection, revealed one electrophysiologically active compound. Structural analysis using gas chromatography, gas chromatography-mass spectrometry, and dimethyldisulfide derivatization identified this as the monounsaturated aldehyde (Z)-7-tetradecenal. Field trials in commercial citrus orchards on the North Island of New Zealand showed that (Z)-7-tetradecenal was highly attractive to male P. nephelomima. Phenology data, collected over 19 months in three commercial orchards, from traps baited with the sex pheromone at a lure loading of 300 microg on a red rubber septum, indicated that male moths may be present throughout the year, with numbers peaking in late summer and autumn.

Performance of irradiated Teia anartoides (Lepidoptera: Lymantriidae) in urban Auckland, New Zealand

The Australian moth Teia anartoides Walker has been the target of a major eradication program in Auckland, New Zealand. Information on cold torpor and dispersal was needed to help interpret catches of sterile and wild males in female-baited delta traps operated in a grid of up to 1,696 traps at 500-m spacings across the city. Laboratory experiments indicated male flight was enabled at temperatures above 17 degrees C (confirmed by field trapping of wild and recaptured moths). Male survival in the field or in field cages was determined to be limited to approximately 4 d. Sterilization of males for dispersal studies was achieved by exposing male pupae to either 160 or 100 Gy by using 1.25 MeV gamma rays from a Cobalt source, before release as fluorescent-dyed emerged adults. Dispersal was determined by recapture of males in the trapping grid of 1,696 delta traps baited with virgin female moths and placed at spacings of 50-500 m. Irradiated sterile males dispersed up to a maximum recorded distance of 4,500 m (160 Gy) and 10,000 m (100 Gy). At 100 Gy, the median dispersal distance was 300 m, with 90% of males dispersing 1,600 m or less.

Identification of sex pheromone components of the painted apple moth: a tussock moth with a thermally labile pheromone component

The sex pheromone of the painted apple moth, Teia anartoides (Lymantriidae) was investigated using GC-EAD and GC-MS analysis, derivatization, TLC analysis, and field cage and field trapping bioassays. The major sex pheromone components were identified as (6Z,9Z)-henicosa-6,9-dien-11-one and (6Z,9Z)-henicosa-6,9-diene. Other minor components of pheromone gland extracts included (6Z)-9R, 10S-epoxyeicos-6-ene, (6Z)-9R,10S-epoxyhenicos-6-ene, (6Z,9Z)-henicosa-6,9-dien-11-ol, (6Z)-henicos-6-en-11-one, and (6Z, 8E)-henicosa-6,8-dien-11-one, but the roles of these minor components remain equivocal. In field cage and field experiments, a blend of all seven identified components [(6Z,9Z)-henicosa-6,9-dien-11-one (relative amount 100), (6Z,9Z)-henicosa-6,9-diene (100), (6Z)-9R,10S-epoxyeicos-6-ene (5), (6Z)-9R,10S-epoxyhenicos-6-ene (10), (6Z,9Z)-henicosa-6,9-dien-11-ol (5), (6Z)-henicos-6-en-11-one (1), and (6Z,8E)-henicosa-6,8-dien-11-one (25)] was as attractive to males as calling females, but tests with blends of the major component(s) with subsets of the minor components did not produce consistent results that unequivocally showed the various minor components to be critical components of the active blend. (6Z,9Z)-henicosa-6,9-dien-11-one is thermally labile and rearranges to (6Z,8E)-henicosa-6,8-dien-1-one and other products at ambient temperature, rendering the synthetic pheromone lure inactive after two days of field exposure.

Uraba lugens (Lepidoptera: Nolidae) in New Zealand: pheromone trapping for delimitation and phenology

A synthetic sex pheromone trapping survey of the leaf skeletonizer Uraba lugens Walker (Lepidoptera: Nolidae) demonstrated the unexpectedly widespread distribution of the insect across > 40,000 ha of urban Auckland, New Zealand. A survey of eucalyptus trees planted in parks and other public areas showed a significant spatial correlation between trap catch and breeding populations, validating the trap survey results. Traps in trees showing damage had four-fold higher catches than traps placed in undamaged or nonhost trees, and < 1% of damaged trees with traps failed to catch adult moths. Damage by larval feeding was correlated with male trap catch in the previous generation, offering good prospects for a pest management decision support system, provided that an economic threshold is developed. Catches increased by 3.4-fold in the same georeferenced trapping grid between November and December 2003 and between March and April 2004 across two generations, over the summer. A vertical transect showed that catches increased with height up to the top trap at 13 m (60% of mean tree height). Options for managing the insect will need to overcome the high rate of increase, the rate of spread, and the vertical distribution of the insect on tall eucalyptus trees.

Effects of substerilizing doses of gamma radiation on adult longevity and level of inherited sterility in Teia anartoides (Lepidoptera: Lymantriidae)

The effects of substerilizing doses of gamma radiation on the longevity and level of inherited sterility in the Australian moth Teia anartoides Walker were determined. Six day-old male pupae were treated with 0, 100, and 160 Gy of gamma radiation by using a 1.25 MeV Cobalt60 irradiation source. Laboratory studies of male longevity showed that radiation had little impact in adult moths of the P1, F1, and F2 generations. Inherited deleterious effects resulting from irradiation were observed in the progeny of F1 and F2 generations. Outcrosses between substerile parental males or their highly sterile male progeny to wild-type females did not affect female fecundity. However, adverse effects were observed for these crosses in the rates of successful egg hatch and postembryonic development. Fertility was always greater in out-crosses involving a P1 male than in any of the F1 out-crosses. F1 males were always more sterile than F1 females, and the level of sterility for the F1 and F2 generations was higher than that of the controls. The incidence of larval and pupal mortality was higher in the F2 than the F1 generation. A dose of 100 Gy had the highest success in inducing deleterious effects that were inherited through to the F2 generation. Our results indicated that the use of partially sterilizing doses of radiation has good potential as a selective strategy for management or eradication of T. anartoides.

Volatile constituents of fermented sugar baits and their attraction to lepidopteran species

The volatile compounds emanating from four fermented sugar baits, palm sugar, golden cane syrup, port wine, and molasses, were isolated by headspace sampling and analyzed by gas chromatography-mass spectrometry. Three classes of compounds including esters, alcohols, and aromatic compounds were identified in the headspace of the four fermented sugar baits. There was a high degree of qualitative similarity between the headspace contents of the four fermented sugar baits, although quantitatively they varied considerably. Ethyl acetate, 3-methylbutanol, ethyl hexanoate, 2-phenylethanol, ethyl octanoate, ethyl (E)-4-decenoate, ethyl decanoate, and ethyl dodecanoate were the major compounds identified in the headspace of the four fermented sugar baits. The efficacy of the four fermented sugar baits was investigated in field trapping experiments. Fermented palm sugar and golden cane syrup were superior in attracting significant numbers of moths as compared to port wine and molasses. Fermented molasses was the least attractive among the four baits. Over 90% of the insects caught were noctuids with Graphania mutans and Tmetolophota spp. being the main noctuids captured (over 55%) in the four fermented sugar baits. Male and female G. mutans were equally attracted to the four sugar baits. A number of tortricid species were also trapped.

Optimization of Pheromone Lure and Trap Characteristics for Currant Clearwing, Synanthedon tipuliformis

Currant clearwing Synanthedon tipuliformis (Sesiidae) has been a pioneering and successful target of mating disruption in New Zealand, with virtually universal black currant industry adoption since c. 1990. Recent unexplained control failures using mating disruption lead to questions about pheromone efficacy. In this study, we have investigated the possible reasons for reduced control from mating disruption, and report improvements in trap catch based on pheromone loading and trap color. No differences were found in electrophysiological responses to pheromone components from two New Zealand populations. Male moth catches in traps baited with synthetic lures were disrupted in the presence of mating disruption dispensers ( > 99.99%) indicating no apparent barrier to efficacy from the pheromone formulation. Field behavioral observations confirmed this result. Male attraction to yellow delta traps was equivalent to green delta traps, but was greater than to red, black, blue, or white traps. Solid yellow delta traps were more attractive than black traps with yellow stripes, the latter designed to mimic the color pattern of the insect. Solid yellow funnel traps were less attractive than a composite of green, yellow, and white funnel traps. Trap catch increased as a function of pheromone loading, and trap color. In another experiment conducted in Tasmania, there was no difference in catch with single component [(E,Z)-2,13-octadecadienyl acetate] or two component lures [97% (E,Z)-2,13-octadecadienyl acetate:3% (E,Z)-3,13octadecadienyl acetate], refuting the suggestion of a different pheromone strain there.

Behavioral and electrophysiological responses of Arhopalus tristis to burnt pine and other stimuli

The exotic longhorn beetle Arhopalus tristis is a pest of pines, particularly those damaged by fire, and a major export quarantine issue in New Zealand. Actinograph recordings of caged individuals showed that males and females were most active from dusk to midnight. Olfactometer experiments indicated that females moved upwind toward odors from burnt pine (80%, N = 75), compared to unburnt pine (20%). Oviposition choice tests showed that eggs were predominantly laid on burnt logs (79%, N = 20), compared to unburnt logs. Beetles were trapped by funnel traps baited with burnt (mean catch per trap 7.8) and unburnt (mean catch 4.1 per trap) pine bark from inside a screen cage (4 x 3 m), while unbaited traps had a mean catch 0.1 beetles (N = 8 replicates). The treatment of burnt pine bark with a 1:1:2 mixture of green leaf volatiles (E)-2-hexen-1-ol and (E)-2-hexenal) in mineral oil as a repellent reduced trap catch by fivefold in a similar experiment (mean catches of 1.2 beetles per trap to burnt pine bark plus repellent treatment and 6.2 beetles per trap to burnt pine bark alone). The treatment of burnt pine bark with this solution also reduced oviposition by 98.5% (mean eggs per log of 11.1 on burnt pine and 0.3 on burnt pine plus repellent), indicating that oviposition cues have the potential to be significantly disrupted. The electrophysiological responses of adult beetles were recorded to a range of odorants. Normalized responses to monoterpenes known to occur in Pinus radiata ranged from about 20 to about 150, with alpha-terpineol giving the greatest responses in both sexes. Green leaf volatiles also gave high responses. The potential exists to improve the management of this insect using chemical cues in various ways.

Simulating the impact of cross resistance between Bt toxins in transformed clover and apples in New Zealand

Simulation were conducted to guide development of resistance management strategies aimed at prolonging the usable life of B. thuringiensis (Bt) endotoxins in multiple cropping situations, where different crops expressing Bt endotoxins are host plants for a common pest. We used the New Zealand apple and clover model ecosystem to explore the relative impact on the rate of resistance development of varying levels of cross-resistance between different toxins expressed in these 2 potentially Bt-transformed crops. These 2 crops are hosts for a complex of leaf-rollers in New Zealand, including the light-brown apple moth, used here as the model pest. Cross-resistance was varied between 0.0 and 0.5 (zero to partial cross-resistance) to allow for the case in which selection by one plant has a potential effect on resistance to the toxin in another plant. The largest factor affecting the evolution of resistance was the total habitat area occupied by transgenic orchards. The proportion of the clover habitat that was transformed was also an important factor, even in the absence of cross-resistance. The effect of increasing the proportion of the second transformed crop (clover) acted on resistance evolution mainly by reducing the external refuge of susceptibility for the transgenic orchards. Hence, the ecological implications of reducing the available source of susceptible insects from clover, which can help to slow resistance development in the orchard ecosystem, had a more significant impact than the presence of cross-resistance. Partial cross-resistance between different toxins in the separate crops was overall of relatively minor importance. These simulations have implications for deployment decisions for individual transformed crops in multiple cropping systems, where there is the potential for the crops to serve as refugees for each other. These decisions may need to focus less on cross-resistance between toxins, than on economic trade-offs between the relative roles of individual crops as refugia maintaining susceptibility in the system as a whole.

Disruption of Light-Brown Apple Moth Epiphyas-Postvittana (Walker) (Lepidoptera, Tortricidae) Trapping in Nelson, New-Zealand

Disruption of lightbrown apple moth trapping was tested as a prelude to assessment of mating dis- ruption; polyethylene dispensers releasing the known sex pheromone components, (E)-11-tetradecenyl acetate and (E,E)-9,ll-tetradecadien-l-yl acetate, at an estimated rate of 25 mg ha-' per hour in apple orchards in Nelson, New Zealand. A total of 2953 wild and 850 laboratory-reared males were marked and released at 16 sites in two pheromone-treated and two untreated blocks. No captures were recorded in sticky traps baited with virgin females or synthetic pheromones in pheromone-treated blocks, but 455 males were caught in untreated blocks, indicating complete prevention of trapping in the presence of the dispensers releasing synthetic pheromone. Individual dispensers released an estimated 4000-fold more pheromone per hour than females. Recapture of wild and laboratory-reared males averaged 28% and 31% respectively, in untreated blocks and surrounding traps. Removal of dispensers resulted in renewed capture inside previously treated blocks. Dispersal distances of wild and laboratory-reared males were not significantly different inside untreated blocks, but the mean time taken before recapture was twice as great for laboratory-reared moths (P<O.05). Wild males showed a greater tendency to disperse out of blocks (P<O.05). Dispersal distances exceeded 400 m for several moths. The daily survival or retention rate of wild moths inside release blocks was estimated to be 63%, although this rose to 74% when external traps were included. A maximum age of 19 days was recorded. Female moths mated with equal frequency when caged with males in pheromone-treated or untreated blocks.