Pre- and postharvest effects of lufenuron on Epiphyas postvittana (Lepidoptera: Tortricidae)

First-, third-, and fifth-instar Epiphyas postvittana (Walker) were exposed to a range of lufenuron concentrations (0-200 ppm) incorporated into synthetic diet and their subsequent development and mortality responses were determined. For all instars the greatest change in mortality response occurred over lufenuron concentrations < or = 3 ppm. However, third and fifth instars displayed an increase in mortality earlier than first instars, and were more sensitive to the lower lufenuron concentrations in this range. Only first and third instars subjected to < or = 2.5 ppm lufenuron survived the 26-d exposure trial. No larvae first exposed to lufenuron as first or third instars survived to pupation if ingesting concentrations of > or = 1 and > or = 3 ppm, respectively. Consumption of lower lufenuron concentrations by these larvae delayed pupation and resulted in pupal deformity. In contrast, fifth instars subjected to 100 ppm were capable of surviving the 26-d trial period and displayed a slower progressive reduction in survival to pupation with increase in lufenuron concentration. Also in contrast to more immature stages, fifth instars exposed to lufenuron developed more rapidly to pupation than larvae not exposed to the insect growth regulator (IGR), and all resulting pupae were normal. Third instars were exposed to sublethal lufenuron concentrations (0-3 ppm) for 4 d and the fourth-instar survivors subjected to a controlled atmosphere cold storage treatment (2% O2, 2% CO2, 0.6 degree C). Larvae ingesting diet containing 0.5 ppm (and to a lesser extent 1 ppm) lufenuron required longer exposure to the postharvest treatment to achieve > or = 95% mortality than larvae not ingesting the IGR. However, the analogous mortality response of larvae exposed to 3 ppm lufenuron was comparable to the control.     

A chemically defined medium for rearing Epiphyas postvittana (Lepidoptera: Tortricidae)

Abstract

The endemic New Zealand genus Neolimnia is redescribed, and a key is given to the 14 species now included. Four new species are described - Neolimnia raiti, N. pepekeiti, N. ura, and N. repo. Two new synonymies are proposed; N. ocellata Tonnoir &; Malloch with N. castanea (Hutton); and N. dubiosa Tonnoir &; Malloch with N. irrorata Tonnoir &; Malloch. Lectotypes are designated for N. tranquilla (Hutton), N. castanea (Hutton), N. obscura (Hutton), and N. striata (Hutton). Male postabdomens of all species are illustrated. Character variation and generic, subgeneric, and species relationships are discussed briefly.     

Light brown apple moth (Epiphyas postvittana) (Lepidoptera: Tortricidae) colonization of California

In response to the confirmed detection of the light brown apple moth, Epiphyas postvittana, in California, approximately 53,000 pheromone-baited Jackson traps were deployed and more than 246,000 males were caught (February 2007–February 2010). Approximately 46,000 manually entered catch records were corrected for errors and converted into catch per trap per day. As empty trap data (zeros) were not recorded, we added zeros between first and last catch for each trap based on the stated servicing period (~30,000), before analyzing for trends. Residual data error rate was estimated as 1.5 %. San Francisco and Santa Cruz counties had relatively high trap catches immediately upon trap set, and remained the leading population centers, while most other counties showed a more general trend of a slow build-up in catch over time (12 counties). An exponential increase in trap catch was observed in four counties with sufficient data. The pattern of spread indicated natural, as well as anthropogenic-assisted spread rates, with populations appearing well ahead of the invasion front. This jump dispersal is probably due to movement of host plants, unsurprising since eggs of this polyphagous moth are readily laid on foliage. There was evidence of seasonality in spread, probably linked to the phenology of the insect. There was a positive relationship between catch and known host tree preference, suggesting that trap placement in preferred hosts could add sensitivity to future surveys. Recommendations include the improved provision of data acquisition by telecommunications, standardization of data input, more archiving, and frequent analysis of trap catches. The rapid rate of population growth demonstrated in two counties and spread across many others supports the hypothesis of the recent arrival of E. postvittana in California.     

Development of Epiphyas postvittana (Lepidoptera: Tortricidae) on leaves and fruit of orange trees

Development of Epipyas postvittna (Walker) (Lepidoptera: Tortricidae), on leaves and fruit of 'Valencia', 'Washington navel', and 'Navelina' orange trees was studied under constant and fluctuating temperatures. E. postvittna was able to complete its life cycle feeding exclusively on leaves or fruit of orange trees. However, larval survival rate was very low (< 20%) on orange tissues compared with that on noncitrus hosts. Among the four types of orange tissues, young orange leaves and fruit afforded larvae higher survival rates than mature orange leaves and fruit. Fruit (young or mature) produced heavier pupae than leaves (young or mature). Larvae developed more slowly on mature orange fruit than on other orange materials and more slowly on orange leaves than on leaves of most noncitrus hosts. Degree-day accumulations based on the fastest developmental rates obtained in this study suggested that E. postvittna is capable of completing 4.4-4.7 generations per year in orange orchards in the Riverina region of New South Wales, Australia. Implications of the results in the management of the insect in citrus are discussed.     

Patterns of mitochondrial haplotype diversity in the invasive pest Epiphyas postvittana (Lepidoptera: Tortricidae)

The light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), is a horticultural pest of Australia and New Zealand that has more recently invaded Hawaii, Europe, and California. A 2,216-bp region of the mitochondrial genome containing the cytochrome oxidase I and II genes was sequenced from 752 individuals. Haplotype network analyses revealed a major split between a predominantly Western Australian clade and all other samples, suggestive of either a deep genetic divergence or a cryptic species. Nucleotide and haplotype diversity were highest in the country of origin, Australia, and in New Zealand populations, with evidence of haplotype sharing between New Zealand and Tasmania. Nucleotide and haplotype diversity were higher in California than within the British Isles or Hawaii. From the total of 96 haplotypes, seven were found in California, of which four were private. Within California, there have been at least two introductions; based on genetic diversity we were unable to assign a likely source for a single moth found and eradicated in Los Angeles in 2007; however, our data suggest it is unlikely that Hawaii and the British Isles are sources of the major E. postvittana population found throughout the rest of the state since 2006.     

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.     

Pheromone binding proteins of Epiphyas postvittana (Lepidoptera: Tortricidae) are encoded at a single locus

The light brown apple moth, Epiphyas postvittana (Tortricidae: Lepidoptera) uses a blend of (E)-11-tetradecenyl acetate and (E,E)-9,11-tetradecadienyl acetate as its sex pheromone. Odorant binding proteins, abundant in the antennae of male and female E. postvittana, were separated by native PAGE to reveal four major proteins with distinct mobilities. Microsequencing of their N-terminal residues showed that two were general odorant binding proteins (GOBPs) while two were pheromone binding proteins (PBPs). Full length cDNAs encoding these proteins were amplified using a combination of PCR and RACE-PCR. Sequence of the GOBPs revealed two genes (EposGOBP1, EposGOBP2), similar to orthologues in other species of Lepidoptera. Eleven cDNAs of the PBP gene were amplified, cloned and sequenced revealing two major phylogenetic clusters of PBP sequences differing by six amino acid substitutions. The position of the six amino acid differences on the protein was predicted by mapping onto the three-dimensional structure of PBP of Bombyx mori. All six substitutions were predicted to fall on the outside of the protein away from the inner pheromone binding pocket. One substitution does fall close to the putative dimerisation region of the protein (Ser63Thr). Expression of three of the cDNAs in a baculovirus expression system revealed that one class encodes an electrophoretically slow form (EposPBP1-12) while the other encodes a fast form (EposPBP1-2, EposPBP1-3). A native Western of these expressed proteins compared with antennal protein extracts demonstrated that PBP is also expressed in female antennae and that PBP may be present as a dimer as well as a monomer in E. postvittana. The fast and slow forms of EposPBP1 are allelic. Westerns on single antennal pair protein extracts and allele-specific PCR from genomic DNA both show a segregating pattern of inheritance in laboratory and wild populations. Radio labelled (E)-11-tetradecenyl acetate binds to both fast and slow PBP forms in gel assays. Taken together, the genetic and biochemical data do not support the hypothesis that these PBPs are specific for each component of the E. postvittana pheromone. However, duplication of this PBP locus in the future might allow such diversification to evolve, as observed in the other species.     

A multiplex real-time polymerase chain reaction assay to diagnose Epiphyas postvittana (Lepidoptera: Tortricidae)

A molecular assay for diagnosis of light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), in North America is reported. The assay multiplexes two TaqMan real-time polymerase chain reaction (RT-PCR) probe systems that are designed to target DNA segments of the internal transcribed spacer region 2 (ITS2) and 18S rRNA gene. The RT-PCR probe designed for the 18S target recognizes a DNA sequence conserved in all of the moths included in the study and functions as a control in the assay. The second probe recognizes a segment of the ITS2 specifically found in E. postvittana and not found in the other moths included in the study, i.e., this segment is not conserved. Inclusion of the two markers in a single multiplex reaction did not affect assay performance. The assay was tested against 637 moths representing > 90 taxa in 15 tribes in all three subfamilies in the Tortricidae. The assay generated no false negatives based on analysis of 355 E. postvittana collected from California, Hawaii, England, New Zealand, and Australia. Analysis of a data set including 282 moths representing 41 genera generated no false positives. Only three inconclusive results were generated from the 637 samples. Spike experiments demonstrated that DNA contamination in the assay can affect samples differently. Contaminated samples analyzed with the ITS2 RT-PCR assay and DNA barcode methodology by using the cytochrome oxidase I gene can generate contradictory diagnoses.     

Multiple mating and its effect on the reproductive success of female Epiphyas postvittana (Lepidoptera: Tortricidae)

Abstract.

• 1 Multiple mating and its effect on reproductive performance of female Epiphyas postvittana (Walker) moths were studied under controlled conditions.
• 2 The age at which the moths mated for the first time ranged from the first to the tenth day after emergence, but 71% of first matings were during the first 3 days.
• 3 The majority (63%) of females had one or two spermatophores in the bursa copulatrix. Some (24%) were found with three to five spermatophores, whereas no successful mating occurred among 13% of individuals. The number of matings was partly dependent on the number of mates available to the female. Between the range of sex ratios of one male to one female and four males to one female maximal mating success occurred at the ratio of three males to one female.
• 4 Virgin females were capable of egg-laying, but mating stimulated and accelerated oviposition. Mated individuals laid twice as many eggs as unmated ones.
• 5 The level of copulatory activity did not influence the longevity of females irrespective of the number of males available to them.
• 6 Sex ratios with greater than one male to a female improved the reproductive success by marginally increasing fecundity and fertility.
• 7 It is concluded that multiple mating would enhance population growth, and is of particular benefit to populations with a preponderance of females, as is known to occur naturally in this species.

     

The hymenopteran parasitoids of light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae) in Australia

Abstract  Epiphyas postvittana (Walker) is a serious pest of a number of horticultural crops including grapes in Australia and New Zealand. This study brings together information on the parasitoid complex associated with E. postvittana that previously was fragmented and largely inaccessible. We include species reared during a 3-year study of the parasitoids of E. postvittana in the vineyards of the Coonawarra region, South Australia, material from several Australian agricultural insect collections and records from the literature. An illustrated key is presented for 25 species of parasitoids and hyperparasitoids associated with E. postvittana , along with information on the taxonomy, identification, distribution and biology of each species. Taxa newly recorded from this host are Perilampus sp. (Perilampidae), and six species of Ichneumonidae: Euceros sp., Labium sp., Netelia sp., Plectochorus sp., Temalucha minuta (Morley) and Eriborus epiphyas sp. n., the latter species being described in full.     

Modeling the potential global distribution of light brown apple moth Epiphyas postvittana (Lepidoptera: Tortricidae) using CLIMEX

Light brown apple moth Epiphyas postvittana is a significant horticultural pest native to Australia that currently has a limited global distribution. However, this pest can tolerate very heterogeneous climates and has a wide host range. It has recently established in California with considerable consequences for US international and domestic trade. It has resulted in increasing calls for targeted risk assessment so that appropriate quarantine measures can be put in place to prevent its entry into new regions and further spread. Potential global distribution has been predicted by comparing the climatic conditions of its native (Australia) and long-established (New Zealand) ranges to the rest of the world using CLIMEX. It was suggested that E. postvittana has potential to establish mainly in countries in Central and South America, southern Africa, Western Europe and Southeast Asia. The study provides basic information for further assessment of the establishment capacity of this species in new habitats, and adds to the knowledge required to make science-based decisions in biosecurity.     

Effect of temperature and treatment conditions on the mortality of Epiphyas postvittana (Lepidoptera: Tortricidae) exposed to ethanol

Morality responses were determined for 5th-instar lightbrown apple moth, Epiphyas postvittana (Walker), in the presence and absence of apples to immersion in ethanol solutions and exposure to ethanol vapor at a range of concentrations, treatment times, and temperatures. Ethanol may have caused an initial knock-down effect in E. postvittana larvae because there was a trend for larval mortality to reduce with increased periods between treatment and assessment time when immersed at 20 degrees C in 30 or 50% ethanol solutions. Mortality for larvae immersed on apples in a range of ethanol concentrations was higher than for larvae in the absence of apples. Increasing treatment temperature from 20 to 45 degrees C during ethanol immersion significantly increased larval mortality. During ethanol vapor exposure, longer treatment times were required to achieve 99% E. postvittana mortality for larvae on apples compared with those in the absence of apples.     

Morphogenetic and physiological effects of a juvenile hormone analogue on the light brown apple moth,Epiphyas postvittana (Lepidoptera: Tortricidae)

Abstract

The juvenile hormone analogue ZR-619—ethyl 11-methoxy-3,7,11-trimethyl-(2E,4E-dodecadienethiolate) —produced morphological and physiological effects when fed via artificial diet to larvae of Epiphyas postvittana (Walker). Morphological effects included changes in larval head and antennal structures after instar V (supernumerary instars); deformation of pupal and adult structures, particularly in genitalia and wings; and development of individuals with varying mixtures of larval and pupal structures. Physiological effects included prolongation of larval life, increase in larval weight, increase in larval instars, and decrease in fecundity. Effects were directly related to dosage concentrations.     

Host Plants Affect the Foraging Success of Two Parasitoids that Attack Light Brown Apple Moth Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae)

The light brown apple moth, Epiphyas postvittana is a key pest of wine grapes in Australia. Two parasitoids, Dolichogenidea tasmanica and Therophilus unimaculatus, attack the larval stage of this pest. D. tasmanica is dominant in vineyards, whereas T. unimaculatus is mainly active in native vegetation. We sought to understand why they differ in their use of habitats. Plants are a major component of habitats of parasitoids, and herbivore-infested plants influence parasitoid foraging efficiency by their architecture and emission of volatile chemicals. We investigated how different plant species infested by E. postvittana could affect the foraging success of the two parasitoid species in both laboratory and field experiments. Four common host-plant species were selected for this study. In paired-choice experiments to determine the innate foraging preferences for plants, both parasitoid species showed differences in innate search preferences among plant species. The plant preference of D. tasmanica was altered by oviposition experience with hosts that were feeding on other plant species. In a behavioral assay, the two parasitoid species allocated their times engaged in various types of behavior differently when foraging on different plant species. For both parasitoids, parasitism on Hardenbergia violacea was the highest of the four plant species. Significantly more larvae dropped from Myoporum insulare when attacked than from the other three host-plant species, which indicates that parasitism is also affected by interactions between plants and host insects. In vineyards, parasitism by D. tasmanica was significantly lower on M. insulare than on the other three host-plant species, but the parasitism rates were similar among the other three plant species. Our results indicate that plants play a role in the habitat preferences of these two parasitoid species by influencing their foraging behavior, and are likely to contribute to their distributions among habitats.     

Defining Interaction between Electroantennogram Responses of Epiphyas postvittana (lepidoptera: Tortricidae) to Pheromone and Other Volatiles

The potential for electroantennograms (EAGs) to assist in the measurement of atmospheric pheromone concentrations was examined in laboratory and field experiments by using multiple stimuli, the main component of the pheromone of Epiphyas postvittana, (E)-11-tetradecenyl acetate, its Z-isomer (a behavioral antagonist), and alpha-terpineol (a representative host-plant odor) were presented to the antenna simultaneously to simulate field conditions. The EAG results were compared with predictions from two models describing responses to combined stimuli. Responses are defined as log-additive if they can be described with the equation [EAG((total)) =a (log ([P(x)]+[B(y)])+c] and as linear-additive if the EAG follows the equation [EAG((total)) =a (log [P(x)])+c+a'(log [B(y)])+c'] where [B(y)] is the concentration of the stimulant background odor and [P(x)] is the concentration of an additional odor stimulus. The EAGs elicited by the added stimuli were inversely related to the concentration of the volatile in the background. EAGs elicited by all combined stimuli followed the log-additive model. Our laboratory results were validated in field tests; alpha-terpineol represents the volatiles present in orchard air. In spite of this interaction between the perception of pheromone and plant volatiles, the field EAG can be used for the measurement of atmospheric pheromone concentrations, where background odor concentrations are relatively constant.     

Increasing vineyard floral resources may not enhance localised biological control of the leafroller Epiphyas postvittana (Lepidoptera: Tortricidae) by Dolichogenidea spp. (Hymenoptera: Braconidae) parasitoids

In agroecosystems, the efficacy of biological control exerted by many parasitoids is predicted to be enhanced where the availability of floral resources is increased. Such resources may attract parasitoids and enhance their longevity and fecundity. In Hawke's Bay, New Zealand, this prediction was tested by adding varying quantities of potted flowering alyssum (Lobularia maritima) (Brassicaceae) to plots containing apple plants (Malus domestica) inoculated with larvae of the leafroller, Epiphyas postvittana (Lepidoptera: Tortricidae). In two replicated trials, over 90% of the parasitoids from recovered larvae were Dolichogenidea spp. (Hymenoptera: Braconidae). In both trials increasing the percentage of alyssum did not result in a corresponding increase in the leafroller parasitism rate. Instead, the primary influence on parasitism rates was due to Dolichogenidea spp. dispersing from a nearby orchard. A significant negative correlation was observed in leafroller parasitism as a function of distance from this orchard. A vineyard to the north of the study site also influenced parasitism rates. Our results suggest the orchard was a regional source population for this parasitoid, and the abundance of local resources such as alyssum did not influence parasitoid foraging. At the level of our entire study block, our effective area of resource provision was 0.1%. A level of resource provision higher than that used in this study may be necessary to test for a positive influence on local parasitism rates. From our results, it appears that for parasitoids with relatively high dispersal rates, the availability of local resources may not be as important as a regional source population.     

Radiation biology and inherited sterility in false codling moth (Lepidoptera: Tortricidae)

False codling moth, Cryptophlebia leucotreta (Meyrick), male and female mature pupae and newly emerged adults were treated with increasing doses of gamma radiation and either inbred or out-crossed with fertile counterparts. For newly emerged adults, there was no significant relationship between dose of radiation and insect fecundity when untreated females were mated to treated males (N female by T male). However, fecundity of treated females mated to either untreated (T female by N male) or treated males (T female by T male) declined as the dose of radiation increased. A similar trend was observed when mature pupae were treated. The dose at which 100% sterility was achieved in treated females mated to untreated males (T female by N male) for both adults and pupae was 200 Gy. In contrast, newly emerged adult males treated with 350 Gy still had a residual fertility of 5.2% when mated to untreated females, and newly emerged adult males that were treated as pupae had a residual fertility of 3.3%. Inherited effects resulting from irradiation of parental (P1) males with selected doses of radiation were recorded for the F1 generation. Decreased F1 fecundity and fertility, increased F1 mortality during development, and a significant shift in the F1 sex ratio in favor of males was observed when increasing doses of radiation were applied to the P1 males.