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Vers-gris ravageurs des cultures dans les Prairies canadiennes: Guide d’identification et mesures de lutte applicables
Abstract and Figures
Le présente guide a pour objet d’aider les producteurs à identifier les espèces nuisibles de vers-gris que l’on retrouve dans les cultures de céréales et d’oléagineux des Prairies canadiennes et à lutter contre ces ravageurs. Le présent document comprend des renseignements généraux sur la biologie et les méthodes de lutte contre ces organismes nuisibles ainsi que des renseignements propres à l’espèce. Nous n’avons pas fourni de liste de produits de lutte chimique homologués contre les vers-gris, car les produits offerts changent fréquemment.
Pour obtenir ces renseignements, les lecteurs sont invités à prendre connaissance des guides de protection des cultures publiés chaque année par les provinces; les liens vers les dernières versions en ligne sont indiqués dans la section Ressources internet à la fin du présent guide.
On trouve également dans ce guide des résumés de recherches menées antérieurement sur le ver-gris, d’anciennes méthodes de lutte et les raisons pour lesquelles certaines méthodes de lutte ne sont plus
recommandées. Des sources de renseignements, dont plusieurs sont accessibles sur le Web, sont citées tout au long du texte. Le contexte historique jumelé aux renseignements à jour permet de relever les lacunes et d’orienter les prochaines recherches. Le suivi des références permet également de simplifier la mise à jour du guide à l’avenir.
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... Peridroma saucia (Hübner, [1808]) (Noctuidae: Noctuinae: Agrotini: Austrandesiina), also known as variegated cutworm, is an owlet moth species that represents potential risk for many cultivated crops around the world (e.g. Crumb 1956;Biezanko et al. 1974;Rings 1977aRings , 1977bHeppner 2003;Pastrana 2004;Lafontaine 2004;Silva et al. 2004;Floate 2017). Their larvae are polyphagous, eat mostly leaves and fruits, and are already associated with more than 130 of herbaceous and tree species (Lafontaine 2004). ...
... Their larvae are polyphagous, eat mostly leaves and fruits, and are already associated with more than 130 of herbaceous and tree species (Lafontaine 2004). Population studies suggest the presence of the species throughout the year (Chittenden 1901;Crumb 1929;Oliver & Chapin 1981;Lafontaine 2004;Moreno & Serna 2006;Floate 2017), and several outbreaks have been occasionally recorded (Chittenden 1901;Crumb 1929Crumb , 1956Walkden 1950;Tietz 1972;Shields et al. 1985;Floate 2017). ...
... Their larvae are polyphagous, eat mostly leaves and fruits, and are already associated with more than 130 of herbaceous and tree species (Lafontaine 2004). Population studies suggest the presence of the species throughout the year (Chittenden 1901;Crumb 1929;Oliver & Chapin 1981;Lafontaine 2004;Moreno & Serna 2006;Floate 2017), and several outbreaks have been occasionally recorded (Chittenden 1901;Crumb 1929Crumb , 1956Walkden 1950;Tietz 1972;Shields et al. 1985;Floate 2017). ...
Peridroma saucia
(Hübner, [1808]) or ‘variegated cutworm’ is a cosmopolitan owlet moth pest resilient and abundant in agroecosystems. However, the morphology of their immatures is only briefly described, and information from distinct life stages is fragmentary. This study describes in detail all immature stages of the species based on a Neotropical population and compares it with populations from other continents and with other cutworm pests found in the Neotropical region. The eggs present useful characters to distinguish P. saucia from other noctuinae pests, such as the number of micropylar openings, and the number and location of aeropyles. The larvae also have unique characters, concentrated on the head capsule (mainly mandibles and spinneret), general color pattern and several aspects on the chaetotaxy. On the other hand, the pupae are remarkably similar to those of cutworms species, although the number of spines on cremaster is potentially a diagnosable character. In general, immature characters can therefore be useful to identify P. saucia regardless of the life stage. These results confirm the relevance of detailed morphological studies on immature of pest species that may be useful to identify and distinguish these individuals without the need of obtaining adults.
The distribution and spread of Noctua pronuba in the eastern United States is reviewed using data collected until the end of the 1994 season. Diagnostic features of the genitalia in both sexes are discussed and illustrated. The rate of spread of N. pronuba in the eastern United States averaged approximately 80 miles per year from 1985-1994.
Wheat leaf consumption by the true armyworm, Pseudaletia unipuncta Haworth, was determined in the laboratory in 1993, 1994, and 1995. Total mean wheat leaf area consumed per larva from eclosion to pupation varied significantly from year to year (77.4-135.4 cm2) with an overall mean leaf area consumed of 103.2 cm2. Wheat field plots were infested with third-instar armyworms and allowed to consume wheat foliage at boot and anthesis stages until preset defoliation levels were met (0, 10, 25, and 50% defoliation in 1993, and 0, 35, 50, 65, and 75% defoliation in 1994, 1995, and 1996). Overall, no significant differences were seen between treatments in number of heads or mean weight of seeds per head in any year suggesting that at boot and anthesis stages Arkansas wheat can sustain up to 75% defoliation by armyworms with little loss in yield. Even at population levels that resulted in 75% defoliation head cutting was negligible.
Zea mays L. (maize) hybrids producing the Cry1F protein from Bacillus thuringiensis were first commercialized in the United States in 2003. These products demonstrated varying levels of moderate control, but not immunity to Striacosta albicosta (Smith) (Lepidoptera: Noctuidae) (western bean cutworm). Susceptibility of western bean cutworm to Cry1F protein was assessed in field populations collected in the mid- and western United States in 2003, 2004, 2013, and 2014 using diet bioassay. A meta-analysis of 32 western bean cutworm field collections assessed for susceptibility to Cry1F was conducted to investigate changes in susceptibility over time. Based on meta-analysis results, these data suggest a 5.2-fold increase in median lethal concentration (LC50) response to Cry1F in the 2013-2014 populations compared with collections that were assessed 10 yr earlier. Widespread use of Cry1F-producing maize hybrids over the past 10 yr may have contributed to favoring western bean cutworm populations with tolerance to the Cry1F protein.
The beet armyworm Spodoptera exigua (Hübner), the black cutworm Agrotis ipsilon (Hufnagel), the silver "y" moth, Phytometra gamma L. (Lepidoptera: Noctuidae) and the diamondback moth Plutella xylostella L. (Lepidoptera: Plutellidae) are serious insect pests of cruciferous crops, particularly oilseed rape in Egypt. Three species of entomopathogenic nematodes (EPN) (Steinernema carpocapsae, Steinernema feltiae and Heterorhabditis bacteriophora) were evaluated against last instar larvae of the previous pest species in laboratory and greenhouse. In the laboratory, the larvae were treated with Infective Juveniles (IJs) at the concentrations of 0, 50, 100, 200, 400 and 600 IJs/larva. Mortality was recorded 72 hours after infection. Data clearly indicated that S. carpocapsae and S. feltiae were more virulent against the four lepidopteran pests, than H. bacteriophora at the all concentrations. At the density of 600 IJs/ larva, S. carpocapse and S. feltiae caused 100% mortality to A. ipsilon, S. exigua and P. xylostella. LC50 values of (EPN) were significantly different depending on the nematode and insect species. Lowest LC50 was obtained by S. carpocapsae with 25.25 IJs/ A. ipsilon larva, 62.98.IJs/ S. exigua larva and 67.90 IJs/ P. xylostella larva, while the highest LC50 was obtained by H. bacteriophora. Results proved that S. carpocapsae was highly efficient under greenhouse conditions when applied at the concentration of 6000 IJs/ 25 ml water directed to larvae on oilseed rape leaves. It caused 74, 72 and 68% mortality to A. ipsilon, P. xylostella and S. exigua, respectively. ©, 2014 Egyptian Society for Biological Control of Pests, All right reserved.
Turfgrass ecosystems contain a variety of generalist predators that may contribute to the regulation of pest insect populations. The black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), is frequently a pest of short-mown golf course greens and fairways and may be a candidate for management by conservation biological control tactics. However, little is known about the susceptibility of different instar A. ipsilon to the many species of carabids, staphylinids, and spiders that inhabit greens, fairways, and roughs. These ecosystems also contain nonpest arthropods that could serve as alternative prey for generalist predators and help bolster their populations. In these laboratory experiments, 12 species of predators, commonly found on golf courses, were evaluated for their ability to consume five different instars of A. ipsilon and for their feeding voracity. The palatability of five potential alternative prey items, to a subset of predators, was also tested. All predator species tested were able to consume at least one instar of A. ipsilon. Two of the most common predators found on golf courses, Amara impuncticollis (Say) (Coleoptera: Carabidae) and Philonthus sp. (Coleoptera: Staphylinidae), could consume all A. ipsilon instars and were also among the most voracious predators tested. In addition, all five alternative prey items were readily eaten by the predator species that were tested. These results suggest that these generalist predators play a role in the regulation of A. ipsilon larval populations on golf courses and that several nonpest arthropod taxa could contribute to attracting and maintaining predator populations.
This volume (71 chapters), the fifth in a series documenting biological control programmes in Canada, presents new information on specific insect, weed or plant diseases, some of which are updates of on-going studies on historical biological control projects while other chapters report on biological control efforts for new emerging invasive alien species. In each case, information is presented in a consistent and logical manner, starting with the pest status in Canada, followed by a comprehensive background on previous studies, review of the use of biological control in these programmes, and an evaluation of the biological control efforts and future needs in research or implementation activities. A total of 64 chapters is dedicated to biological control case studies over the past 11 years - 36 on insect pests of agricultural importance and forestry or ornamental pests; 18 on the control of weeds for crops, rangeland, pastures or aquatic areas; and 10 on the biological control of plant disease causal agents. This book is intended for researchers and students in biological control, pest management, ecology and risk assessment.