Characterization of Triazine-Resistant Biotypes of Common Lambsquarters (Chenopodium album), Hairy Fleabane (Conyza bonaeriensis), and Yellow Foxtail (Setaria glauca) Found in Spain

Abstract

Triazine-resistant (R) biotypes of common lambsquarters, yellow foxtail, and hairy fleabane were found in the Province of Córdoba (Andalusia, Southern Spain). The former two R biotypes came from atrazine-treated cornfields, whereas the latter came from simazine-treated nontilled olive orchards. The R biotypes of common lambsquarters and yellow foxtail and the R biotype of hairy fleabane survived at doses up to 5 kg ai/ha of soil-applied atrazine or simazine, respectively. Photosynthetic electron transport in R biotypes was unaffected by atrazine and simazine but was inhibited by diuron, as shown by fluorescence induction measurements in whole leaves. In Hill reaction assays, the R biotypes showed high resistance to atrazine and simazine (resistance factors in the range of 350 to 550), medium to high resistance to ametryn, terbumeton, metribuzin, and monolinuron (resistance factors in the range of 80 to 250), slight resistance to diuron and methabenzthiazuron (resistance factors in the range of 1.1 to 15.7), and reverse resistance to swep, ioxynil, and DNOC (resistance factors less than 1). It is concluded that the R biotypes have a chloroplast mode of resistance similar to that previously described for other triazine-resistant weed biotypes.

Triazine resistance in biotypes of Solanum nigrum and four Amaranthus species found in Spain

“…Seeds of susceptible (S) biotypes of these weed species were collected from adjacent areas that had never been treated with triazine herbicides. Seed germination and plant growth conditions were as described previously (De Prado et al, 1989).…”

“…However, there were no reports on the occurrence in Spain of weeds resistant to triazines. We have recently reported the appearance of triazine-resistant biotypes of Chenopodium album, Conyza bonariensis and Setaria glauca in the province of C6rdoba (Andalusia, Southern Spain) (De Prado et al, 1989). Later surveys carried out in maize fields and non-tiUage olive orchards, where atrazine or simazine had been applied continuously for the last 8 years, showed the presence oi Amaranthus albus, A. blitoides, A. hybridus, A. retroflexus and Solanum nigrum populations which were no longer controlled by these herbicides.…”

Effects of chloroacetamides and phytosynthesis‐inhibiting herbicides on growth and photosynthesis in sunflower (Helianthus animus L.) and Amaranthus hybridus L.

“…Isolated broken chloroplasts were obtained from leaves of 4-week-old sunflower and S and R A. hybridus plants as described by De Prado et al (1989). The Hill reaction (ferricyanide as electron acceptor) was measured in a Clark-type teflon-coated O2 electrode in the presence of the photosynthesis-inhibiting herbicides linuron.…”

Photosynthetic activity and chloroplast structural characteristics in triazine‐resistant biotypes of three weed species

“…Plants were grown in a fertilized peat-sandy loam mixture io the greenhouse under natural sunlight (maximum photoo flux density of around 2 ODD [xmol m~-s"'). Seed germination and other plant growth conditions were as described elsewhere (De Prado et al 1989). Leaves from 28-day-old plaots were used.…”

“…We recently reported the first appearance of triazine resistance in Spain, describing the insensitivity to triazine herbicides of biotypes of Ckenopodium album, Cortyza bonaeriensis and Setaria glauca found in the province of Cordoba (Andalusia, Southern Spain;De Prado et al 1989). To further characterize these resistant (R) biotypes, we have in the present paper studied their photosyothetic activity, chloroplast structure aod lipid composition.…”