Ford, G. 2015. Glyphosate-resistant kochia (Kochia scoparia L. Schrad.) in Saskatchewan and Manitoba. Can. J. Plant Sci. 95: 345Á349. Previous surveys have documented the occurrence of glyphosate-resistant (GR) kochia in Alberta in 2011 and 2012. To determine the incidence of GR kochia in Saskatchewan and Manitoba, a stratified-randomized survey of 342 sites (one population per site) in southern and central regions of Saskatchewan and a similar survey of 283 sites in southern Manitoba was conducted in the fall of 2013. Mature plants were collected, seed threshed, and progeny screened by spraying with a discriminating glyphosate dose of 900 g ae ha Á1 under greenhouse conditions. Screening confirmed 17 GR kochia populations in nine municipalities in west-central or central Saskatchewan, but only two GR populations from different municipalities in the Red River Valley of Manitoba. While the majority of GR kochia populations in Saskatchewan originated in chemicalfallow fields, some populations were found in cropped fields (wheat, Triticum aestivum L.; lentil, Lens culinaris Medik.; GR canola, Brassica napus L.) and non-cropped areas (oil well, roadside ditch). In Manitoba, the two populations occurred in fields cropped to GR corn (Zea mays L.) and soybean (Glycine max L. Merr.). Agronomic and economic impact of this GR weed biotype is compounded because of consistent multiple resistance to acetolactate synthase-inhibiting herbicides. However, GR kochia is susceptible to dicamba, an increasingly important auxinic herbicide used for control of this multiple-resistant weed biotype. Pour e´tablir l'incidence de cette adventice GR en Saskatchewan et au Manitoba, les auteurs ont proce´deá`u ne enqueˆte ale´atoire stratifie´e a`342 sites (un peuplement par site) dans le sud et le centre de la Saskatchewan, puis ont effectue´une enqueˆte similaire a`283 sites dans le sud du Manitoba, a`l'automne 2013. Ils ont recueilli des plants matures, en ont re´colte´les graines et ont pre´se´lectionne´la proge´niture en la pulve´risant avec 900 g de glyphosate par hectare, en serre, aux fins de discrimination. La pre´se´lection a confirme´la pre´sence de 17 peuplements de kochie GR dans neuf municipalite´s du centre-ouest ou du centre de la Saskatchewan, mais seulement deux populations GR dans des municipalite´s diffe´rentes de la valle´e de la rivie`re Rouge, au Manitoba. Bien que la majorite´des peuplements de kochie GR de la Saskatchewan aient e´te´observe´s dans des jache`res chimiques, quelques-uns ont e´te´retrouve´s dans des cultures (ble´, Triticum aestivum L.; lentille, Lens culinaris Medik.; canola GR, Brassica napus L.) et sur des terrains en friche (puits de pe´trole, fosse´d'une route). Au Manitoba, les deux populations ont e´te´de´couvertes dans des champs de maı¨s GR (Zea mays L.) et de soja (Glycine max L. Merr.). L'impact agronomique et e´conomique de cette adventice GR est complexe, car la kochie pre´sente une re´sistance multiple aux herbicides qui inhibent l'ace´tolactate synthase. Ne´anmoins, la kochie GR est sen...

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Phorate is an acetylcholinesterase-inhibiting organophosphate pesticide used for the control of insects, mites and nematodes. In cultivated peanut (Arachis hypogaea L.), phorate is often used as an in-furrow, systemic insecticide to reduce thrips populations which vector tomato spotted wilt tospovirus (TSWV). However, phorate-induced suppression of disease incidence and severity is not solely due to thrips control because other pesticides control thrips but not TSWV. The present research was focused on understanding the biochemical and molecular components of the phorate-induced host responses that may condition acquired resistance to TSWV in peanut. Phorate treatments adversely affected maximal quantum yield of the light reactions (F v /F m ). A dose-dependent increase in ascorbic acid content and in activities of the oxidative stress-related enzymes, catalase and superoxide dismutase was evident following phorate treatment, whereas the level of glutathione reductase was not affected. An RT-PCR differential display screen identified 35 expressed sequence tags (ESTs) responsive to phorate treatment in peanut leaves. Functional annotations revealed transcriptional regulation of ESTs implicated in primary and secondary metabolism including photosynthesis-related genes, mitigation of oxidative stress, signalling pathways and pathogenesis-and defence-related proteins. Two ESTs encoding membrane trafficking functions were downregulated, which may reflect reduced internalization and/or subsequent replication of viral particles in phorate-treated leaves. Time-course quantitative RT-PCR analyses further verified fidelity and sensitivity of the mRNA differential display screen and corroborated that systemic spread of TSWV in field-grown plants is reduced following phorate application. The m elange of differentially regulated gene functions is consistent with a model in which a phorateinduced breach of redox control culminates in hypersensitive cell death and subsequent induction of systemic acquired resistance.