Wild radish (Raphanus raphanistrum L.) is a problematic and economically damaging dicotyledonous weed infesting crops in many regions of the world. Resistance to the auxinic herbicides 2,4-D and dicamba is widespread in Western Australian R. raphanistrum populations, with the resistance mechanism appearing to involve alterations in the physiological response to synthetic auxins and in plant defense. This study aimed to determine whether these alterations cause inhibition in plant growth or reproduction that could potentially be exploited to manage 2,4-D–resistant populations in cropping areas. Therefore, the morphology and seed production of resistant and susceptible populations were compared in an outdoor pot study, with plants grown in the presence and absence of competition by wheat (Triticum aestivum L.). The susceptible and resistant R. raphanistrum populations were equally suppressed by wheat competition, with plant growth and seed production being decreased by approximately 50%. Although resistant populations produced less vegetative biomass than susceptible populations, there was no negative association between resistance and seed production. Therefore, it is unlikely that any nonherbicidal management practices will be more efficacious on 2,4-D–resistant than 2,4-D–susceptible R. raphanistrum populations.

In Senegal, damage caused by insect pests is a major obstacle to seasonal stability and an increase in cabbage production. Little is known about the spatial and temporal distribution of cabbage pests, which makes the design of management recommendations to small-scale farmers challenging. The objectives of this study were to: (i) evaluate the status of insect pests observed in cabbage farmers’ fields; (ii) give information on the spatial and temporal distribution of key pests and (iii) assess the effect of temperature, insecticide applications, and host crop abundance on their incidence. A total of 116 cabbage fields were monitored for insect pests and related damage over four crop cycles, from October 2012 to May 2014, in the main vegetable producing area of Senegal (Niayes). The diamondback moth Plutella xylostella (L.) was by far the most important pest present in all the fields and with high levels of incidence (37.1% infested plants), particularly in the latter part of the dry season in the South of Niayes (50% infested plants). The cabbage webworm Hellula undalis (F.) was mainly observed in the early dry season in the south of Niayes, with an incidence of up to 12.5% infested plants. More surprising was the detection of the tomato fruit worm Helicoverpa armigera (Hübner), with damage of up to 9.4% of cabbage heads. The incidence of sucking pests such as whiteflies Bemisia tabaci (Gennadius), or aphids (including Lipaphis pseudobrassicae (Davis, 1914), Myzus persicae (Sulzer) or Brevicoryne brassicae (L.)) was generally low. The incidence of P. xylostella increased significantly with the number of insecticide applications, indicating that control deployed by growers was ineffective. The incidence of H. undalis did not depend on the number of insecticide applications, but significantly increased with host crop abundance and decreased with temperature. This study is a first step towards developing alternative pest management strategies in the framework of sustainable vegetable production systems.

Defatted seedmeals from 15 glucosinolate-containing plant species were analyzed for herbicidal activity by determining inhibition of seedling emergence when added to a sandy loam soil containing wheat and sicklepod seeds at concentrations of 0.1, 0.5, and 1% (w/w). In general, the seedmeals were more phytotoxic to wheat than sicklepod. For wheat, all of the seedmeals significantly inhibited seedling emergence at the 1.0% concentration. At the 0.1% concentration three of the seedmeals (Indian mustard, money plant, and field pennycress) completely inhibited wheat emergence. For sicklepod emergence, eight of the seedmeals were completely inhibitory at the 1% level (Indian mustard, field pennycress, garden rocket, Siberian wallflower, English wallflower, garden cress, sweet alyssum, and evening stock) and four were completely inhibitory at the 0.5% level (brown mustard, garden rocket, English wallflower, and sweet alyssum). Intact glucosinolates and their corresponding hydrolysis products varied among the seedmeals with the highest activity. Major hydrolysis products produced by the seedmeals with the most phytotoxicity, respectively, included 2-propenyl (allyl) isothiocyanate (AITC) by brown mustard seedmeal, allyl thiocyanate and AITC by field pennycress seedmeal, erucin (4-methylthiobutyl isothiocyanate) by arugula seedmeal, 3-butenyl isothiocyanate and lesquerellin (6-methylthiohexyl isothiocyanate) by sweet alyssum seedmeal, and isopropyl isothiocyanate by money plant seedmeal. From our data it appears that both the type and concentration of glucosinolates and their hydrolysis products present in the seedmeals affect seed-emergence inhibition.

The allelopathic potential of hoary cress was evaluated by exposing the seeds and the germinated seeds of winter wheat, alfalfa, crested wheatgrass, bluebunch wheatgrass, and hoary cress to a water extract of dried, hoary cress roots under controlled conditions in an environmental chamber. Germination for all species was reduced in the hoary cress root extract when compared with distilled water, with winter wheat and hoary cress being more tolerant than the other species. Root length of all species was reduced by the extract when compared with distilled water. These data show the presence of phytotoxic chemical(s) that may inhibit germination and initial seedling growth in natural environments. Three glucosinolate compounds were identified in hoary cress root extracts.

The allelopathic potential of wild radish was evaluated in controlled environments by determining if an aqueous extract from oven-dried wild radish shoots suppressed germination and radicle growth of some crops and weeds common to the southeastern United States. In addition, phytotoxicity from topical applications of the aqueous extract was assessed, along with crop and weed suppression by soil incorporated, air-dried wild radish residues. Germination and radicle growth of all species were reduced by the extract compared with distilled water. However, topical applications of the aqueous extract failed to induce injury on any species by 7 d after treatment. Emergence and shoot fresh weight of the bioassay plants were reduced by wild radish residue incorporated into soil, with the level of suppression dependent on the quantity of residue incorporated. Sicklepod and prickly sida were extremely sensitive to incorporated wild radish residues, with > 95% fresh weight reduction at 0.5% (wt/wt) residue, compared with an untreated control. Conversely, yellow nutsedge showed a high degree of tolerance in all trials. Of the crops evaluated, cotton emergence and growth were most sensitive to incorporated wild radish residues. These data indicate that wild radish aqueous extract or incorporated residues (or both) suppress seed germination, radicle growth, seedling emergence, and seedling growth of certain crops and weeds and these responses are attributed to an allelochemical effect.

Plutella xylostella (L.) is the most important pest of Brassicaceae worldwide, with a recent estimate of US$ 4–5 billion expenditure for the control of this insect. A case of very high resistance of this pest to chlorantraniliprole was recently associated with reduced efficacy in a Brazilian field of Brassica spp. Although diamide resistance has been characterized, the fitness of insects due to such resistance has yet to be examined. Therefore, in this study, biological parameters were assessed in both susceptible and resistant strains of P. xylostella subjected to sublethal chlorantraniliprole concentrations. The field strain showed high resistance to chlorantraniliprole (RR50=27,793-fold), although resistance rapidly decreased in the first generations, showing instability. The exposure of susceptible and resistant larvae to their respective LC1, LC10, and LC25 values led to an increased duration of the larval and pupae phases and reduced weight in both strains; however, no significant differences in pupal viability across the treatments were observed. The resistant insects presented significantly lower larval weight and fecundity and higher larval and pupal periods, hatchability, and male longevity when not exposed to chlorantraniliprole, suggesting a fitness cost associated with resistance. In addition, resistant females showed a significantly higher egg-laying period and longevity at LC25, whereas the males lived longer at LC1. Chlorantraniliprole negatively impacted the biological parameters of both strains tested, although these effects were more relevant to the resistant insects. Resistant P. xylostella showed negative and positive biological trade-offs when compared with the susceptible individuals in both the absence and presence of chlorantraniliprole. Despite the important role that these trade-offs may play in the evolution of resistance to chlorantraniliprole, practical applications still depend on such information as the dominance of fitness costs and resistance.

The genus Stubendorffia (Brassicaceae) is distinguished from Lepidium solely by the dehiscent vs. indehiscent angustiseptate fruits. By contrast, Winklera is separated from Lepidium by a combination of perennial habit, pinnatisect leaves, yellow flowers, and wingless fruits, characters all of which occur individually and in various combinations within Lepidium. Extensive molecular studies strongly show that Winklera and polyphyletic Stubendorffia are nested within the earlier-published Lepidium and, therefore, the three genera are herein formally united. The new name Lepidium pavlovii and 10 new combinations, L. afghanicum, L. apterum, L. botschantzevii, L. curvinervium, L. lipskyi, L. olgae, L. orientalis, L. patrinoides, L. pterocarpum, and L. silaifolium, are proposed. Lepidium apterum is lectotypified. A complete generic synonymy of Lepidium and an expanded generic description are presented.

Rechinger, in his 1968 Flora Iranica account, considered Sterigmostemum to contain nine species in Iran. In 1980 Léonard excluded S. purpurascens from Sterigmostemum and transferred it to the new genus Petiniotia as P. purpurascens. Subsequently, in 1988 Jacquemoud retained this species in Sterigmostemum, but as subgenus Petiniotia. In 2000 Sonboli et al. excluded S. laevicaule from Sterigmostemum and considered it to be a synonym of Erysimum crassicaule. Phenetic analysis of morphological and anatomical characters from herbarium and fresh specimens supports the recognition of five species in Sterigmostemum (S. incanum, S. sulphureum, S. acanthocarpum, S. ramosissimum and S. longistylum). The results of cluster analysis and ordination based on these characters confirm Léonard's exclusion of S. purpurascens and transfer to the genus Petiniotia as P. purpurascens. A key is provided to distinguish Petiniotia from Sterigmostemum, followed by descriptions of the two genera and a conspectus of species.

A new species of Alyssum L. (Cruciferae) from Western Turkey is described and illustrated: Alyssum dudleyi N. Adıgüzel & R.D. Reeves.

Under defined laboratory conditions it was shown that two glucosinolate-containing plant species, Tropaeolum majus and Carica papaya, were colonized by arbuscular mycorrhizal (AM) fungi, whereas it was not possible to detect AM fungal structures in other glucosinolate-containing plants (including several Brassicaceae). Benzylglucosinolate was present in all of the T. majus cultivars and in C. papaya it was the major glucosinolate. 2-Phenylethylglucosinolate was found in most of the non-host plants tested. Its absence in the AM host plants indicates a possible role for the isothiocyanate produced from its myrosinase-catalysed hydrolysis as a general AM inhibitory factor in non-host plants. The results suggest that some of the indole glucosinolates might also be involved in preventing AM formation in some of the species. In all plants tested, both AM hosts and non-hosts, the glucosinolate pattern was altered after inoculation with one of three different AM fungi (Glomus mosseae, Glomus intraradices and Gigaspora rosea), indicating signals between AM fungi and plants even before root colonization. The glucosinolate induction was not specifically dependent on the AM fungus. A time-course study in T. majus showed that glucosinolate induction was present during all stages of mycorrhizal colonization.

The generic name Microsisymbrium O.E. Schulz was illegitimate when described because it included the type of Guillenia Greene. The monotypic Ianhedgea is proposed to include one of the 12 species previously assigned to Microsisymbrium, i.e. M. minutiflorum (Hook.f. & Thomson) O.E. Schulz. The proper generic placement of the remaining 11 species of Microsisymbrium is presented. The following new combinations are made: Ianhedgea minutiflora (Hook.f. & Thomson) Al-Shehbaz & O'Kane, I. minutiflora subsp. brevipedicellata (Hedge) Al-Shehbaz & O'Kane, and Neotorularia quingshuiheense (Ma & Z.Y. Zhu) Al-Shehbaz, O'Kane & G. Yang.