Sex pheromone of pear moth, Cydia pyrivora

The sex pheromone of the pear moth, Cydia pyrivora, is (E,E)-8,10-dodecadien-yl acetate. A 5%-addition of the geometric isomers E,Z and Z,Z decreased male attraction in the field, the Z,E isomer had no significant effect. Traps baited with 10 µg E,E on grey rubber septa were attractive throughout the flight period of C. pyrivora. These traps allow specific detection of pear moth, and they are not attractive to its sibling species, codling moth C. pomonella.     

Horizontal Escape of the Novel Tc1-Like Lepidopteran Transposon TCp3.2 into Cydia pomonella Granulovirus

We characterized an insertion mutant of the baculovirus Cydia pomonella granulovirus (CpGV), which contained a transposable element of 3.2 kb. This transposon, termed TCp3.2, has unusually long inverted terminal repeats (ITRs) of 756 bp and encodes a defective gene for a putative transposase. Amino acid sequence comparison of the defective transposase gene revealed a distant relationship to a putative transposon in Caenorhabditis elegans which also shares some similarity of the ITRs. Maximum parsimony analysis of the predicted amino acid sequences of Tc1- and mariner-like transposases available from the GenBank data base grouped TCp3.2 within the superfamily of Tc1-like transposons. DNA hybridization indicated that TCp3.2 originated from the genome of Cydia pomonella, which is the natural host of CpGV, and is present in less than 10 copies in the C. pomonella genome. The transposon TCp3.2 most likely was inserted into the viral genome during infection of host larvae. TCp3.2 and the recently characterized Tc1-like transposon TC14.7 (Jehle et al. 1995), which was also found in a CpGV mutant, represent a new family of transposons found in baculovirus genomes. The occasional horizontal escape of different types of host transposons into baculovirus genomes evokes the question about the possible role of baculoviruses as an interspecies vector in the horizontal transmission of insect transposons. Received: 27 February 1997 / Accepted: 16 May 1997     

Effect of substrate formulation on the efficacy of the pea moth, Cydia nigricana, sex pheromone lures

Field experiments have shown that the activity of (E,E)-8,10-dodecadien-1-yl acetate, the sex pheromone of the pea moth, Cydia nigricana (F.) (Lepidoptera, Tortricidae), is significantly affected by the type of rubber substrate used for the preparation of dispensers. Rubber substrates cured with elemental sulphur or accelerators based on organic sulphur compounds isomerized pea moth pheromone faster than rubber substrates cured by organic peroxides. The degree of isomerization increased during field use and/or storage. Average catches of males were further dependent on the release rate of pheromone from the dispenser. In a 2×3 factorial experiment arranged in 6×6 Latin square design a statistically highly significant dispenser x dose interaction was demonstrated (P<0.01).

---

Résumé Dans la nature, l'action de (E,E)-8,10-dodécadien-1-yl-acétate, phéromone sexuelle de C. nigricana F., est significativement modifiée par le type de caoutchouc utilisé poùr la réalisation du diffuseur. Le caoutchouc vulcanisé du soufre ou avec des accélérateurs à base de composés soufrés isomérise la phéromone sexuelle de C. nigricana plus rapidement que le caoutchouc vulcanisé avec des péroxydes organiques. Le taux d'isomérisation augmente pendant l'utilisation dans la nature et/ou pendant le stockage. Les captures moyennes de mâles dépendent avant tout de la libération de la phéromone par le diffuseur. Une étude de 2×3 facteurs organisée en carré latin (6×6) a mis en évidence une interaction hautement significative entre diffuseur et dose (P<0,01).

     

Tebufenozide distorted codling moth larval growth and reproduction, and controlled field populations

The activity of the ecdysteroid agonist tebufenozide was evaluated on the codling moth, Cydia pomonella. Tebufenozide affected larval feeding and growth, showing clear symptoms of a double head capsule. Under the SEM and TEM, symptoms of precocious apolysis of the larval integument were observed. Although this process was accompanied with a great inhibition of locomotion, muscle attachment to the new cuticle seemed not to be affected confirming the primary mode of action of tebufenozide as ecdysteroid‐like. In addition, tebufenozide exerted a sterilising action in female and male adults in the laboratory. Finally, the potency of tebufenozide was evaluated in an experimental orchard for commercial apple production in Belgium being, at least, as effective as diflubenzuron.     

The occurrence and distribution of resistance of codling moth to Cydia pomonella granulovirus in Europe

Thirty‐five codling moth (CM, Cydia pomonella L., Lepidoptera, Tortricidae) populations collected in different commercial orchards in six European countries were tested for their susceptibility to Cydia pomonella granulovirus (CpGV‐M). Including previously published data on CpGV‐M resistance, a total of 38 CM colonies showed considerably elevated LC₅₀ values, independent of the country origin. When only few test individuals are available, determination of mortality of neonate larvae at a discriminating concentration range of 10⁴ to 10⁶ OB/ml (>log4) as a direct measure of percentage susceptible individuals in a CM population is more advisable than calculation of LC₅₀ values. The >log4 mortality alone or in combination with the LC₅₀ value can be used for identification of resistance in a population. Results indicated a locally separated but widely spread occurrence of CM populations with low susceptibility to CpGV‐M. The most plausible hypothesis for the emergence of CpGV‐M resistance is its selection by repeated use of CpGV products.     

Combined approaches using sex pheromone and pear ester for behavioural disruption of codling moth (Lepidoptera: Tortricidae)

Attractive properties of pear ester, ethyl (E,Z)‐2,4‐decadienoate, and codlemone, (E,E)‐8,10‐dodecadien‐1‐ol, the sex pheromone of codling moth, Cydia pomonella (L.), were utilized in experiments on behavioural disruption of mating. Standard dispensers loaded with codlemone alone or in combination with pear ester (combo) were applied at 500–1000/ha. Larger (10‐fold) combo dispensers (Meso) were evaluated at a rate of 80/ha. The addition of microencapsulated pear ester, PE‐MEC, sprayed with insecticides at 30 ml/ha was also evaluated. Male moth catches in unmated female‐baited traps were lower in standard combo dispenser than in codlemone dispenser–treated plots. Female moth catch in traps baited with the combination of pear ester, codlemone and acetic acid was lower in standard combo dispenser than in codlemone dispenser–treated plots. In 12 comparative experiments spanning from 2006 to 2012, male moth catch in unmated female‐baited traps was consistently and significantly lower in combo than in codlemone dispenser–treated plots. Male catch in codlemone‐baited traps did not differ between dispenser treatments in eight studies from 2006 to 2009. These results emphasize the benefit of alternatively using traps baited with unmated females over codlemone lures for the analysis of dispenser activity. Fruit injury was significantly reduced with the addition of PE‐MEC to insecticide applications across untreated and dispenser treatments. Proportion of unmated females trapped was higher in standard combo dispenser than in codlemone dispenser–treated and untreated plots. Similarly, the proportion of unmated females caught was higher in the Meso combo dispenser than in nearby or distant codlemone dispenser–treated plots. These field studies conducted in apple over 3 years demonstrate that adding pear ester both to pheromone dispensers, either standard or Meso, and to supplementary insecticide sprays can provide a significant increase in the disruption of sexual communication, reductions in female mating and reductions in fruit injury.     

Monitoring oriental fruit moth and codling moth (Lepidoptera: Tortricidae) with combinations of pheromones and kairomones

Experiments were conducted in North and South America during 2012–2013 to evaluate the use of lure combinations of sex pheromones (PH), host plant volatiles (HPVs) and food baits in traps to capture the oriental fruit moth, Grapholita molesta (Busck), and codling moth, Cydia pomonella (L.), in pome and stone fruit orchards treated with sex pheromones. The combination of the sex pheromone of both species (PH combo lure) significantly increased G. molesta and marginally decreased C. pomonella captures as compared with captures of each species with either of their sex pheromones alone. The addition of a HPV combination lure [(E,Z)‐2,4‐ethyl decadienoate plus (E)‐β‐ocimene] or acetic acid used alone or together did not significantly increase the catch of either species in traps with the PH combo lure. The Ajar trap baited with terpinyl acetate and brown sugar (TAS bait) caught significantly more G. molesta than the delta trap baited with PH combo plus acetic acid in California during 2012. The addition of a PH combo lure to an Ajar trap significantly increased catches of G. molesta compared to the use of the TAS bait or PH combo lure alone in 2013. Female G. molesta were caught in TAS‐baited Ajar traps at similar levels with or without the use of additional lures. Ajar traps baited with the TAS bait alone or with (E)‐β‐ocimene and/or PH combo lures caught significantly fewer C. pomonella than delta traps with sex pheromone alone. Ajar traps with 6.4‐mm screened flaps caught similar numbers of total and female G. molesta as similarly baited open Ajar traps, and with a significant reduction in the catch of non‐targets. Broader testing of HPV and PH combo lures for G. molesta in either delta or screened or open Ajar traps is warranted.     

Cocoon-spinning larvae of Oriental fruit moth and Indianmeal moth do not produce aggregation pheromone

1 Mature larvae of the Oriental fruit moth (OFM) Grapholita molesta (Lepidoptera: Tortricidae) and the Indianmeal moth (IMM) Plodia interpunctella (Lepidoptera: Pyralidae) leave their food source in search of suitable pupation sites in which to spin cocoons. These sites are typically well-concealed cracks and crevices within the environment. Such cocooning behaviour is also observed in larvae of the codling moth (CM) Cydia pomonella (Lepidoptera: Tortricidae), which aggregate prior to pupation in response to a pheromone blend produced by cocoon-spinning conspecific larvae.
2 In laboratory experiments, we tested whether cocoon-spinning OFM and IMM larvae produce aggregation pheromones and whether CM larvae are cross-attracted to closely-related OFM larvae.
3 Fifth-instar OFM and IMM larvae were not attracted to, or arrested by, cocoon-spinning conspecifics. Moreover, fifth-instar CM larvae were not cross-attracted to either cocoon-spinning OFM or IMM larvae.
4 Analyses of volatiles released from cocoon-spinning OFM and IMM larvae revealed that both OFM and IMM lack components that are present in the aggregation pheromone of CM larvae. This information may help explain why CM larvae are not cross-attracted to cocooning OFM or IMM larvae.     

Does aggregation behavior of codling moth larvae,Cydia pomonella,increase the risk of parasitism by Mastrus ridibundus?

Mastrus ridibundus is a specialist hymenopteran parasitoid that parasitizes last-instar larvae or prepupae of the codling moth, Cydia pomonella. Foraging females eavesdrop on an aggregation pheromone produced by cocooning larvae. We investigated whether larvae that cocoon in aggregation experience a greater rate of parasitism than larvae that cocoon in isolation. In wind tunnel experiments, 10 larvae in aggregations were more readily located by female M. ridibundus than 10 larvae well separated from each other. Similarly, aggregations of 30 larvae were more attractive to female M. ridibundus than those of 3 larvae. In cage experiments, larval cocooning in aggregation or isolation had no effect on the mean rate of parasitism and the mean number of eggs deposited per parasitized host. In Petri-dish experiments, the location of larvae within an aggregation significantly affected their rate of parasitism, with those in the center of an aggregation completely shielded from parasitism. Our data suggest that aggregation behavior by C. pomonella larvae does not appear to increase the rate of parasitism. The increased risk of aggregated larvae to be detected by M. ridibundus is likely offset by diluted parasitism risk and structural refugia effects that larvae in aggregation experience. As an egg-limited parasitoid, female M. ridibundus can parasitize on average only one larva in an aggregation, with the likelihood of parasitism for each larva being inversely proportional to the number of larvae in that aggregation.     

Effect of host egg viability on reproduction and development of Trichogramma cacoeciae and T. principium (Hymenoptera: Trichogrammatidae)

A combination of a sterile insect technique, resulting in infertile eggs, and of an egg parasitoid, should provide better control of codling moth than either alone. Non-choice laboratory experiments were conducted with infertile and fertile codling moth eggs to evaluate the potential parasitism and reproduction of Trichogramma cacoeciae Marchal and T. principium Sug. et Sor. The tendency of T. cacoeciae females to attack infertile eggs was similar to that for fertile eggs, whereas T. principium showed a greater preference for infertile eggs than fertile eggs. The fertility status of the host did not affect the number of eggs that were parasitized but fewer F₁ progeny emerged from infertile eggs when parasitized than from fertile eggs. When T. cacoeciae and T. principium parasitized infertile host eggs their mean developmental time was prolonged but the viability and quality of parasitoid progeny was not influenced by the fertility status of the host eggs. The study demonstrates the compatibility of use of T. cacoeciae and T. principium in an integrated program employing the sterile insect technique for codling moth management.