EFFECT OF TEMPERATURE ON TOXICITY OF BACILLUS THURINGIENSIS TO THE OBLIQUEBANDED LEAFROLLER (LEPIDOPTERA: TORTRICIDAE)

1995 ◽  
Vol 127 (2) ◽  
pp. 271-273 ◽  
Author(s):  
S.Y. Li ◽  
S.M. Fitzpatrick ◽  
M.B. Isman

In recent years, the obliquebanded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae), has become a major pest of raspberries in the Fraser Valley, British Columbia (Anonymous 1994). Overwintering C. rosaceana larvae begin feeding on raspberry leaf buds in early April. Heavy infestation causes serious damage to raspberry plants. Larvae of the first generation hatch in late June to early July, and feed on growth terminals and berries. The occurrence of this generation usually coincides with berry harvesting time. Because the larvae are shaken from the plants by the harvesting machine, C. rosaceana can be a major contaminant of machine-harvested berries.

1986 ◽  
Vol 118 (4) ◽  
pp. 351-359 ◽  
Author(s):  
M.T. AliNiazee

AbstractSeasonal history, adult flight activity, and damage of the obliquebanded leafroller, Choristoneura rosaceana (Harris), on filbert were studied during a 7-year period between 1976 and 1984. Data from periodic field counts and moth catches in sex-attractant traps indicated two generations per year. The first-generation adult capture peak was generally higher than the second, except in 1978 when about an equal number of moths were trapped from both generations. A physiological time scale, using degree-days (DD), was devised for predicting emergence of obliquebanded leafroller adults. The first adults from overwintering larvae emerged at approximately 374 DD above a threshold of 10 °C starting 1 March. A total of 1172 DD were required between the first and the last adult emergence during the first generation and about 519 DD during the second generation. The obliquebanded leafroller causes both foliar and nut damage in filbert orchards of Oregon. Foliar damage was insignificant, but nut damage, caused exclusively by the first-generation larvae during June and early July, was highly destructive. Larval feeding on nuts caused staining and premature drop of infested nuts resulting in substantial yield reduction in heavily infested orchards.


2005 ◽  
Vol 82 (2) ◽  
pp. 73-82 ◽  
Author(s):  
J.-C. Côté ◽  
C. Vincent ◽  
K.-H. Son ◽  
S. H. Bok

DiPelTM, a registered Bacillus thuringiensis var. kurstaki (Btk)-based formulation, and experimental bio-encapsulated Btk formulations were sprayed in an apple orchard. Their persistence was assessed in the laboratory against obliquebanded leafroller (Choristoneura rosaceana) larvae for three consecutive years. In 1995, DiPel and the bio-encapsulated formulation caused significantly higher larval mortality than the control at least 1 day, and up to 27 days after treatments, respectively. In 1996, although 6.4 mm of rain fell during the day of treatments, DiPel and the bio-encapsulated formulation caused respectively 21 and 33% larval mortality immediately after treatments. DiPel caused significantly higher mortality than the control for up to 3 days while the bio-encapsulated formulation caused significantly higher mortality for up to 14 days. In 1997, two Btk strains (HD-1 and BMP123) were sprayed at different concentrations in a.i. (3 and 8%) and doses (30 and 240 g 15 L-1 applied). Higher concentrations of a.i. in the Btk formulations and higher doses sprayed increased the persistence of the insecticidal activity. Among the meteorological factors that were measured (i.e. precipitations, temperature and solar radiations), precipitations reduced the persistence of the insecticidal activity. Solar radiations may have modulated the persistence of the formulations.


1984 ◽  
Vol 116 (12) ◽  
pp. 1659-1664 ◽  
Author(s):  
H. F. Madsen ◽  
J. M. Vakenti ◽  
A. P. Gaunce

AbstractThe 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.


1999 ◽  
Vol 131 (3) ◽  
pp. 399-404 ◽  
Author(s):  
S.Y. Li ◽  
S.M. Fitzpatrick ◽  
J.T. Troubridge ◽  
M.J. Sharkey ◽  
J.R. Barron ◽  
...  

AbstractFourteen species of parasitoids (13 hymenopterans, 1 dipteran) were reared from larvae or pupae of the obliquebanded leafroller, Choristoneura rosaceana (Harris), collected from commercial raspberry fields in the Fraser Valley, British Columbia, Canada, over 3 years. Levels of parasitism ranged from 5 to 15%. Among these 14 species, five represent new host records. A polyembryonic wasp, Macrocentrus nigridorsis Viereck (Hymenoptera: Braconidae), was the most abundant parasitoid. External feeding on the final host instar is obligatory for M. nigridorsis to complete development. On average, each parasitized host larva produced about 36 M. nigridorsis, in either unisexual or mixed-gender groups. Overall male to female sex ratio was 1:4. Head capsules of mature parasitized host larvae were significantly larger than those of unparasitized ones, suggesting that C. rosaceana larvae parasitized by M. nigridorsis might have an extra larval stage.


2001 ◽  
Vol 133 (1) ◽  
pp. 139-146 ◽  
Author(s):  
J.M. Vakenti ◽  
J.E. Cossentine ◽  
B.E. Cooper ◽  
M.J. Sharkey ◽  
C.M. Yoshimoto ◽  
...  

AbstractEighteen 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.


1996 ◽  
Vol 128 (4) ◽  
pp. 605-612 ◽  
Author(s):  
S.Y. Li ◽  
S.M. Fitzpatrick

AbstractThe relative toxicities of two formulations (Dipel WP and Foray 48B) of Bacillus thuringiensis Berliner var. kurstaki to the obliquebanded leafroller, Choristoneura rosaceana (Harris), were determined in the laboratory. The effects of application rate (BIU per hectare) and spray volume (litres per hectare) on the efficacy of Dipel WP and Foray 48B against C. rosaceana were determined in raspberry fields. Mortality of C. rosaceana increased with application rate, and decreased with an increase in spray volume. Bacillus thuringiensis exhibited significantly longer residual activity al higher application rates and at lower spray volumes. The half-life (time at which 50% of original activity remains) of B. thuringiensis ranged from 2.45 to 6.68 days, depending upon application rate and spray volume. Laboratory and field studies indicate that Dipel WP and Foray 48B are highly and equally effective in killing larvae of C. rosaceana.


1995 ◽  
Vol 127 (4) ◽  
pp. 577-586 ◽  
Author(s):  
Y. Carrière ◽  
S. Paré ◽  
B.D. Roitberg

AbstractThe daily pattern of oviposition, the rank order of oviposition preference for three potential hosts, and the effect of experience on oviposition preference were investigated under natural abiotic conditions in the obliquebanded leafroller, Choristoneura rosaceana. Females from the two adult cohorts occurring seasonally oviposited between 0400 and 2400 hours, with peak oviposition around 2000 hours. Both non-choice and choice oviposition trials revealed that the apple and snowberry hosts were preferred over wild rose. Oviposition preference resulted in delays in laying on the less preferred host, but seemed to have no effect on clutch size. Females caged with exclusive access to one of the three hosts appeared to have similar lifetime fecundity or longevity. A first oviposition on wild rose resulted in a delay in laying a second clutch on that host, which suggests the presence of aversive learning that could function to reduce the liklihood of laying successive clutches on a less preferred host. A first oviposition on the apple host, however, seemed to have no effect on further oviposition preference. Hence, it appears that learning would not function specifically to concentrate foraging of the females within apple orchards.


Plant Disease ◽  
2013 ◽  
Vol 97 (4) ◽  
pp. 559-559 ◽  
Author(s):  
J. F. Elmhirst ◽  
B. E. Auxier ◽  
L. A. Wegener

Boxwoods (Buxus spp.) are common woody ornamental hedging plants in Europe and North America, typically propagated by cuttings. In October 2011, shoot dieback and defoliation was observed on Buxus sempervirens ‘Suffruticosa’ (dwarf English boxwood) and ‘Green Balloon’ in outdoor, 10-cm pots at a wholesale nursery in Chilliwack, British Columbia. Circular leaf spots with black rings occurred on leaves and black, water-soaked, cankers girdled the stems and petioles. Leaf and stem samples were collected on November 21, 2011, and incubated for 48 h in a moist chamber at room temperature. In addition to Volutella buxi, a Cylindrocladium species producing conidia on white sporodochia was observed on host tissue under the microscope. Leaves with lesions were surface-sterilized in 10% bleach for 30 to 60 s, rinsed in sterile water, and lesions were cut out and plated on PDA and carnation leaf media. The species was identified as Cylindrocladium pseudonaviculatum Crous, J.Z. Groenew. & C.F. Hill 2002 by comparison of conidia and phialide morphology to published descriptions. Conidia were hyaline, one-septate, cylindrical with rounded ends and 38 to 76 μm (mean 51 μm) × 4 to 6 μm on carnation leaf media and 41 to 66 μm (mean 52 μm) × 4 to 6 μm on B. sempervirens ‘Suffruticosa’ leaves, comparable to the reported range of 40 to 75 × 4 to 6 μm (1,2,3,4). Conidia were produced in clusters on terminal, ellipsoid vesicles at the tips of penicillate conidiophores. Vesicles were 10.2 (7.6 to 12.8 μm) at the widest point, consistent with the 6 to 11 μm reported in (2,3) and tapered to a rounded point; stipe extensions were septate and measured an average of 130 μm (107 to 163 μm) in length to the tip of the vesicle, consistent with the 95 to 155 μm reported in (1), 89 to 170 μm reported in (2), and 95 to 165 μm in (3). Chlamydospores were not observed on host tissue but appeared in older PDA cultures as dark brown microsclerotia. DNA was extracted from single-spore colonies on PDA and the internal transcribed spacer (ITS) region of rDNA was amplified with primers ITS1 and ITS4. The ITS sequence (GenBank Accession No. KC291613) was 100% identical to C. buxicola strain CB-KR001 (HM749646.1) and Calonectria pseudonaviculata strain ATCC MYA-4891 (JX174050.1). In early December 2011, box blight was identified on container-grown B. sinica var. insularis × B. sempervirens ‘Green Velvet,’ ‘Green Gem’, and ‘Green Mountain’ and B. sempervirens L. (common or American boxwood). The pathogen was identified by microscopic examination at three wholesale nurseries in the eastern Fraser Valley and one landscape planting. The isolate has been deposited in the Canadian Collection of Fungal Cultures in Ottawa, Canada (DAOM 242242). References: (1) B. Henricot and A. Culham. Mycologia 94:980, 2002. (2) K. L. Ivors, et al. Plant Dis. 96:1070, 2012. (3) C. Pintos Varela, et al. Plant Dis. 93:670, 2009. (4) M. Saracchi, et al. J. Plant Pathol. 90:581, 2008.


1994 ◽  
Vol 126 (4) ◽  
pp. 1061-1065 ◽  
Author(s):  
Kees van Frankenhuyzen

AbstractThe relationship between temperature and pathogenesis of Bacillus thuringiensis Berliner var. kurstaki in infected larvae of the eastern spruce budworm, Choristoneura fumiferana Clem., was investigated to determine if more rapid death of larvae with an increase in temperature could be accounted for by enhanced bacterial growth. Cumulative mortality of larvae force-fed with a lethal dose of HD-1-S-1980 peaked within 2 days at 25 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C. The progress of bacterial growth in the larvae was followed from spore germination to cell lysis, and was completed within 4 days at 25 °C, 6 days at 22 °C, 12 days at 19 °C, 14 days at 16 °C, and > 28 days at 13 °C. Peak abundance of vegetative cells in the larvae was observed after 1 day at 25 °C, 2 days at 22 °C, 3 days at 19 °C, 7 days at 16 °C, and 21 days at 13 °C, and thus coincided almost exactly with the time required for maximum larval mortality. This correlation suggests that the observed effect of temperature on progression of larval mortality was due to its effect on the proliferation of vegetative cells in the infected larvae, and that bacterial septicemia makes an important contribution to death.


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