Emergence of overwintered larvae of eye-spotted bud moth, Spilonota ocellana (Lepidoptera: Tortricidae) in relation to temperature and apple tree phenology at Summerland, British Columbia

We recorded daily appearance of overwintered larvae of eye-spotted bud moth (ESBM), Spilonota ocellana (Denis & Schiffermüller) in spring 1992, 1994, and 1996 in an unsprayed apple orchard at Summerland, British Columbia, to relate larval emergence to degree-day (DD) accumulation and apple phenology. In all years the first larva was found between mid-March and early April, and none appeared after late April. Median emergence of larvae occurred when McIntosh apple trees were at early, tight-cluster stage of fruit-bud development. Larval head capsule measurements showed that ESBM usually overwinter as fifth and sixth instars, with a small proportion (≤6%) as fourth instar larvae. In the laboratory we monitored emergence of non-diapausing overwintered larvae from apple branches incubated at 8.8, 9.4, 12.9, 15.0, 18.0, and 20.9ºC. A least-squares linear regression described emergence over this temperature range relatively accurately (r2 = 0.57, P < 0.05) and a base temperature for emergence (Tb = 1.0ºC ± 0.6) was extrapolated from this regression. Regression analysis indicated median emergence should require 154.6 ± 6.7 DD above 1ºC (DD 1ºC). Using daily airtemperature maxima and minima and 1 March to start accumulating DD1ºC, the error between predicted and observed days to median emergence in the field was -6.7 ± 3.1 d; the regression model predicted early in every case. Using observed larval appearance on apples (1992, 1994, & 1996) and an iterative process, we determined that a combination of 6ºC as the Tb and 1 January as a date to start accumulating DD6ºC, minimized the coefficient of variation for the three-year mean DD 6ºC accumulations (82.7 ± 3.5 DD 6ºC) required for 50% of the larvae to appear in the field. While this latter DD index described observed emergence of larvae accurately, and its use may help improve management of ESBM, it should be validated using independent data before growers use it routinely

First record of the Western Grape Leafhopper, Erythroneura elegantula Osborn (Homoptera: Cicadellidae), in Canada

Surveys conducted in the South Okanagan Valley, British Columbia, revealed that a new leafhopper pest of grapes, the western grape leafhopper (WGL), Erythroneura elegantula Osborn, was widespread and often abundant in Vineyards on the east side of the Valley from just north of Penticton south to the United States border. Infestations occurred on drier upland sites where most commercial grape production occurs. The largest populations of up to 40 nymphs per leaf were recorded from commercial Vineyards that had applied reduced rates of the insecticide carbaryl for control of the Virginia creeper leafhopper, E. ziczac Walsh

Temperature, irradiation and delivery as factors affecting spring-time flight activity and recapture of mass-reared male codling moths released by the Okanagan-Kootenay sterile insect programme

Laboratory flight-tunnel and field mark-release-recapture experiments were conducted to compare pheromone response, flight activity and recapture of wild codling moths, Cydia pomonella (L.), with codling moths mass-reared by the Okanagan-Kootenay Sterile Insect Release Programme. These experiments were designed to identify factors that may contribute to poor pheromone trap catches of sterile moths in the spring. Irradiation (250 Gy) had no influence on catches of n1ass-reared moths in pheromone traps at spring (16°C) or summer temperatures (25°C) in flight-tunnel assays. In field experiments however, recapture of n1ass-reared and wild moths in pheromone traps was significantly reduced after irradiation, suggesting effects of irradiation were modified by additional factors acting in the field. Catches of mass-reared moths in flight-t1mnel assays showed a nonlinear increase with increasing temperature. There was no evidence that n1ass- reared moths were less responsive to pheromone at low temperatures than wild moths. Based on x-intercepts of linear regressions of percent catch vs. temperature (15 - 25°C), flight-temperature thresholds for mass-reared (14.7°C) and wild moths (15.4°C) were similar in flight-tunnel assays. Irradiated moths carried for 4 h on all-terrain vehicles used for delivering sterile moths were less responsive to pheromone lures in subsequent flight-tunnel assays than moths that spent no time on these vehicles, but only when flown at spring-like temperatures (16°C). In field tests, moths released on the ground were caught significantly less often than moths released within the tree canopy and negative effects of ground release appeared greater when made in spring compared with autumn

Simultaneous disruption of pheromone communication and mating in Cydia pomonella, Choristoneura rosaceana and Pandemis limitata Lepidoptera:Tortricidae) using Isomate-CM/LR in apple orchards

Simultaneous disruption of pheromone communication and mating of codling moth, Cydia pomonella (L), and four leafroller (Lepidoptera:Tortricidae) species, Choristoneura rosaceana (Harris), Pandemis limitata (Robinson), Archips rosanus (L.) and Archips argyrospilus (Walker ) using an incomplete mixture of their individual pheromone components was studied in organic apple orchards, in Cawston, BC, 1997. Multi-species disruption with a single 500 'rope' dispenser / ha application of Isomate-CM/LR was compared to a single 500 dispenser / ha application of Isomate-C. Season-long disruption was assessed using synthetic pheromone traps and laboratory-reared females in mating tables. Mean seasonal recaptures of sterile male C. pomonella, using 10 mg codlemone lures in orchards receiving releases of 1000 males / ha / week, were not significantly different in half-orchard plots (0.5 - 1 ha) of Isomate-CM/LR or Isomate-C. Mating of C. pomonella in Isomate-C- and Isomate-CM/LR-treated plots was negligible. Isomate-CM/LR significantly reduced catches of C. rosaceana and P. limitata relative to catches in Isomate-C-treated plots. Few A. rosanus and no A. argyrospilus were caught in any orchard. Mating of C. rosaceana and P. limitata in Isomate-CM/LR treated plots was significantly less than in Isomate-C-treated plots. Our results indicate Isomate-CM/LR will disrupt mating of C. pomonella equivalent to Isomate-C and may provide sufficient disruption of leafrollers to supplement biological control in organic orchards. Further studies are needed to show impacts of mating disruption on leafroller populations and damage when applied to larger areas and for several seasons sequentially

Leafhopper host plant associations for Anagrus parasitoids (Hymenoptera: Mymaridae) in the Okanagan Valley, British Columbia

Anagrus spp. are important natural regulators of leafhoppers infesting grapes, tree fruits, and other crops in south central British Columbia (BC). Predominantly four species of these egg parasitoids, A. atomus (L.), A. avalae Soyka, A. daanei Triapitsyn, and A. erythroneurae Triapitzyn and Chiappini, were reared from dormant host plants and from summer host plants in the Okanagan Valley. The largest numbers of Anagrus specimens were collected from roses, Rosa spp; blackberry, Rubus spp; apple, Malus domestica; and other members of the rose (Rosaceae) family. Species of mint, family Lamiaceae, were important host plants for several species, with lavender, Lavendula angustifolia, and garden sage, Salvia oficinalis, being both a summer and winter host plant for some species. The most likely leafhopper host on these plants is the mint leafhopper, Eupteryx melissae Curtis. This study contributes to our knowledge of the biology of Anagrus species in south central BC and could contribute to future efforts to preserve or enhance populations of these beneficial insects

Antennal detection of sex pheromone by female Pandemis limitata (Robinson) (Lepidoptera: Tortricidae) and its impact on their calling behaviour

Previous observations lead us to believe that female Pandemis limitata (Robinson) (0 to 24 h old) are as attractive as their pheromone gland extract to males in clean air, but are more attractive in an environment permeated with their major pheromone component(Z)-11-tetradecenyl acetate. Therefore, in this study, we tested the hypothesis that females can detect and/or respond to their pheromone components. Using electroantennographic detection, we found female P. limitata able to perceive both of their known pheromone components, (Z)-11-tetradecenyl acetate and (Z)-9-tetradecenyl acetate. Female antennal response was found to be 46.3% weaker than that of males, under identical conditions, with male antennae producing significantly higher deflections to the higher pheromone doses tested and to the plant volatile,(E)-2-hexanal. Observations of females in clean air versus (Z)-11-tetradecenyl acetate-permeated air showed no significant differences with respect to onset time, frequency or duration of calling. Females moved significantly less often in a (Z)-11-tetradecenyl acetate-permeated portion of a flight tunnel than in the corresponding clean-air portion

Almond volatiles attract neonate larvae of Anarsia lineatella (Zeller) (Lepidoptera: Gelechiidae)

Post-diapause overwintered larvae and neonates of any generation of the peach twig borer, Anarsia lineatella (Zeller), seek suitable sites to bore into and mine tissue of their host plants, including almond and peach. We tested the hypothesis that larvae are attracted to the same almond volatiles that elicit antennal responses from adult moths. Of five candidate almond semiochemicals [β-bourbonene, (E,E)-α-farnesene, (E)-β-ocimene, nonanal, decenal] tested singly or in binary combination (nonanal, decenal) in laboratory Y-tube olfactometers, only β-bourbonene attracted neonate larvae. β-bourbonene in combination with (EE)-α-farnesene was as attractive as the complete almond volatile blend, indicating that they are key semiochemicals for foraging larvae