Trapping Pandemis limitata (Lepidoptera: Tortricidae) moths with mixtures of acetic acid, caterpillar-induced apple-leaf volatiles, and sex pheromone

Pandemis limitata (Robinson) (Lepidoptera: Tortricidae) is one of several leaf-feeding caterpillar pests of commercial tree-fruit crops in British Columbia, Canada. Recent discovery that European Pandemis Hübner species are attracted by lures combining acetic acid and the caterpillar-induced apple-leaf volatiles, 2-phenylethanol, and phenylacetonitrile, prompted our examination of P. limitata response to these compounds. Trapping tests in organic apple orchards revealed that neither of these individual benzenoids, nor their binary combination, was attractive. Acetic acid alone was weakly attractive, but more importantly, catches increased significantly when an acetic-acid co-lure was combined with 2-phenylethanol or phenylacetonitrile, individually and together. Catches of male and female P. limitata with acetic acid+2-phenylethanol, or acetic acid+2-phenylethanol+phenylacetonitrile were similar, respectively, and both sexes were caught significantly less often in traps baited with acetic acid+phenylacetonitrile. When combined with acetic-acid co-lures, traps baited with membrane dispensers releasing 2-phenylethanol at ~1 mg/day caught significantly more moths than traps baited with rubber septa lures releasing 2-phenylethanol at ~0.6 mg/day. Moth catches in traps baited with 2-phenylethanol were unaffected when the emission of acetic-acid co-lures was increased from ~28 to 63 mg/day. Catches of male P. limitata in traps baited with sex pheromone were significantly greater than catches in traps baited with acetic acid+2-phenylethanol, or traps baited with a ternary blend of acetic acid+2-phenylethanol+sex pheromone. Catches of female P. limitata in traps baited with acetic acid+2-phenylethanol were significantly reduced when it was combined with sex pheromone. Use of the ternary acetic acid+2-phenylethanol+phenylacetonitrile blend provides an opportunity to develop multispecies bisexual trapping systems to improve management of sympatric tortricid pests currently causing economic losses in organic apples in British Columbia. More work on long-lasting release devices, nonsaturating traps, and organically acceptable killing agents are needed to develop organic mass-trapping systems.

Attraction of male Pandemis limitata (Lepidoptera: Tortricidae) to natural and synthetic pheromone sources: importance for assessing communication disruption

In flight-tunnel assays in both clean and pheromone-permeated air, we compared attraction and behavioural responses of male Pandemis limitata (Robinson) to “calling” females, female pheromone gland extract (FGE), and synthetic sources of pheromone. In clean air, female-baited traps caught significantly more males than traps baited with rubber septa lures loaded with 10 or 100 µg of the known pheromone components ((Z)-11-tetradecenyl acetate (Z11-14:Ac) and (Z)-9-tetradecenyl acetate) blended in a 91:9 or 94:6 ratio. Traps baited with septa loaded with 500 µg of the 94:6 blend caught as many males as did female-baited traps. Proportions of males engaging in wing fanning, take-off flight, locking onto the plume, and upwind flight towards a rubber septum loaded with 100 or 500 µg of the 94:6 blend were not significantly different from proportions exhibiting these behaviours in response to calling females. Only 500 µg lures elicited as much source contact in the same time as did a calling female. In clean air, traps baited with FGE applied to filter paper at 5 or 10 female equivalents caught as many males as did calling females. In air treated with Z11-14:Ac applied as a pheromone disruptant, females attracted more males and did so sooner than did five equivalents of FGE on filter paper. Consequently, disruption of male orientation to calling females was significantly shorter (74 h) than disruption of orientation to FGE (146 h). However, FGE dispensed from a piezoelectric microsprayer at a rate equivalent to 50 pg of Z11-14:Ac·min–1 caught as many males as a calling female. At this delivery rate, two-choice microsprayer bioassays revealed that FGE containing the two known components at a 91:9 ratio was more attractive than a synthetic blend of these two pheromone components alone at the same ratio. In air permeated with Z11-14:Ac, disruption of orientation to this FGE lasted 74 h, equivalent to disruption of orientation to females. These results suggest the published two-component pheromone blend for P. limitata is likely incomplete, and in the absence of suitable synthetic attractants, we recommend use of calling females or FGE delivered using a microsprayer system for any laboratory examination of communication disruption in this species.

Host-plant range and parasitoids of obliquebanded and three-lined leafrollers (Lepidoptera: Tortricidae)

Eighteen parasitoid species were found associated with obliquebanded leafroller, Choristoneura rosaceana (Harris), and three-lined leafroller, Pandemis limitata Robinson, from 1982 to 1984, on apple and other host plants in the southern interior of British Columbia. The leafroller parasitoids included a Glypta Gravenhorst species (Hymenoptera: Ichneumonidae), Diadegma eureka (Ashmead) and Diadegma interruptum pterophorae (Ashmead) (Hymenoptera: Ichneumonidae), and Hemisturmia tortricis (Coquillett) (Diptera: Tachinidae). The two leafroller species were found on 18 wild host plants from 10 plant families.

VESICAS OF SELECTED TORTRICID AND SMALL LEPIDOPTEROUS SPECIES, WITH DESCRIPTIONS OF NEW TECHNIQUES OF VESICA EVERSION (LEPIDOPTERA: TORTRICIDAE, OECOPHORIDAE, GELECHIIDAE, AND NEPTICULIDAE)

Vesicas of the following tortricid and other small lepidopterous species are described and illustrated: Tortricidae: Orthotaenia undulana (Denis and Schiffermüller), Apotomisfrigidana (Packard), Olethreutes appendiced (Zeller), Evora hemidesma (Zeller), Epinotia nanana (Treitschke), Corticivora clarki Clarke, Atchips packardiana (Fernald), Pandemis limitata (Robinson), and Aethes rutilana (Hübner); Oecophoridae: Psilocorsis quercicella Clemens; Gelechiidae: Dichomeris flavocostella (Clemens); and Nepticulidae: Obrussa ochrefasciella (Chambers).The injection and chemical induction techniques of eversion of vesicas of tortricid moths and other Lepidoptera are described.

DISTRIBUTION AND FLIGHT ACTIVITY OF OBLIQUEBANDED AND THREELINED LEAFROLLERS (LEPIDOPTERA: TORTRICIDAE) IN THE OKANAGAN AND SIMILKAMEEN VALLEYS OF BRITISH COLUMBIA

The distribution and adult flight activity of obliquebanded leafroller, Choristoneura rosaceana (Harris) and threelined leafroller, Pandemis limitata (Rob.) were studied in the Okanagan and Similkameen valleys of British Columbia using traps baited with the sex pheromone of each species. Adult activity began in early June and continued through September and the two species were distributed throughout the apple-growing region of the Okanagan and Similkameen valleys. In the northern Okanagan and in uncultivated areas at higher elevation, the trap captures indicated that both species are univoltine. In the southern Okanagan and the Similkameen Valley, large numbers of both species were captured throughout the season which may indicate more than one generation. Traps captured similar numbers of adults in orchards with known infestations and in orchards lacking infestations, suggesting that males are attracted to traps in orchards from native hosts in uncultivated sites.