摘要:

AbstractA simple mathematical model of the life‐cycle ofAvena fatuaL. is described and used to consider the financial consequences to the farmer of controllingA. fatuainfestations in winter wheat. The likely economic benefits of applying herbicides in different cultivation regimes are investigated. The sensitivity of the model to variations in herbicide performance, straw burning, initial weed infestation and the value of the wheat crop is tested. The model predicts that the highest long‐term benefits will be obtained when a herbicide is applied every time wild oats exceed a density of between 2 and 3 seedlings m−2. Whether or not this results in a significant financial saving over spraying every year depends on the initial level of infestation and on the cultivation method. Whether straw is burnt or not is likely to be of little economic signifi

ISSN:0031-613X    

DOI:10.1002/ps.2780170102

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractRationally planned structural modifications were carried out on benzylphenols and benzyl‐1,3‐benzodioxoles described as fly chemosterilants and as anti‐juvenile hormones. The introduction of a prop‐2‐ynyloxy group at various sites of the molecule resulted in compounds with a moderate inhibitory action on cytochrome P‐450 mono‐oxygenases, as measured by aldrin epoxidation. One compound, 5‐(4‐methoxybenzyl)‐6‐prop‐2‐ynyloxy‐1,3‐benzodioxole, revealed chemosterilant activity onPhormia regina, but its activity was less than that of the parent compounds. 2,4‐Di‐tert‐butyl‐6‐[4‐(3‐methoxy‐3‐methylbutoxy)benzyl]phenol, which possessed a juvenoid structure, revealed no juvenile hormone (JH) activity but showed a high sterilant effect againstDysdercus cingulatus. In contrast to the parent substances, none of the tested compounds showed a detectable anti‐JH effect in theGalleriaassay. 8‐Methoxy‐2,3‐methylenedioxydibenz[b,e]oxepine, a hitherto undescribed fused heterocyclic ring system, was devoid of activity, indicating the importance of free rotation and/or molecular flexibility. In spite of the moderate activities of these compounds, the manifold biological potential of the quinone‐me

ISSN:0031-613X    

DOI:10.1002/ps.2780170103

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe efficacies of nine structural analogues of the herbicide antidote naphthalene‐1,8‐dicarboxylic acid anhydride (naphthalic anhydride, NA) for the protection of maize (Zea maysL. cv. DeKalb XL72AA and DeKalb XL67) against injury by the herbicideS‐ethyl dipropyl(thiocarbamate) (EPTC) were elevated under greenhouse conditions. The chemical analogues of NA tested were: acenaphthenequinone (ACQ); 4‐aminonaphthalene‐1,8‐dicarboxylic acid anhydride (NH2NA); 1,8:4,5‐naphthalenetetracarboxylic acid dianhydride (NDiA); naphthalene‐ 1,8‐carboximide (NHNA); 4‐chloronaphthalene‐1,8‐dicarboxylic acid anhydride (C1NA); biphenyl‐2,2′‐dicarboxylic acid anhydride (diphenic anhydride; DA); 2‐phenylglutaric anhydride (PGA); phthalic anhydride (PHA); phenalen‐1‐one (PA). Pre‐plant incorporated applications of EPTC at 2.2, 4.5, 6.7, and 9.0 kg ha−1were highly toxic to XL67 maize. Appreciable injury to XL72AA maize by EPTC was observed only with the high rates of EPTC (6.7 and 9.0 kg ha−1). Of the analogues tested PGA and PA were very toxic and inhibited germination of both maize hybrids. NA, ACQ, NH2NA, NDiA, NHNA, C1NA, DA, and PHA applied as seed dressings at 5.0 and 10 g per kg of seed offered satisfactory protection to XL72AA maize against EPTC rates higher than 6.7 kg ha−1. The same antidotes significantly antagonised the EPTC activity against XL67 maize but the overall protection obtained was partial and not agronomically important. The presence of the dicarboxylic anhydride group and of at least one aromatic ring attached directly to the anhydride appeared to be essential for the exhibition of protective activity by the structural analogues of NA. NA was slightly toxic to both hybrids of maize and chlorination of NA increased the phytotoxicity of this molecule. A genetic component that is present in the thiocarbamate‐tolerant XL72AA hybrid but absent from the thiocarbamate‐susceptible XL67 hybrid of maize appeared to be important for the phytotoxic activity of EPTC and may be involved in the protect

ISSN:0031-613X    

DOI:10.1002/ps.2780170104

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

Abstract3‐Hydroxyendrin, a minor metabolite of endrin in several mammals, has been synthesised for the first time in a three‐step procedure. The synthesis is based on the two‐step commercial manufacture of endrin, with cyclopenta‐1,3‐dienyl acetate replacing cyclopentadiene in the Diels‐Alder adduction step to isodrin formation. The adduct formed from cyclopenta‐1,3‐dienyl acetate and 1,2,3,4,7,7‐hexachlorobicyclo‐[2.2.1]hepta‐2,5‐diene, 3‐acetoxyisodrin, was purified by chromatography and sequentially deacetylated (to 3‐hydroxyisodrin) and epoxidised to yield 3‐hydroxyendrin. A comparison of this material with a sample of a metabolite, isolated from endrin‐dosed rates in 1970, showed that they were identical in all spectral properties (m.s., i.r. and n.m.r.). This has provided confirmation of the original structural assignment and has made available sufficient quantities of the metabolite as a reference material for any futur

ISSN:0031-613X    

DOI:10.1002/ps.2780170105

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe phloem translocation of an homologous series of ω‐(1‐[1‐4C]naphthoxy)alkanoic acids relative to that of applied [6,6′‐3H] sucrose was measured inRicinus communisvar. Gibsonii. Relative phloem mobility decreased with increase in octan‐l‐ol/water partition coefficients. However, non‐ionisable compounds with partition coefficients similar to the readily translocated acids were not phloem mobile. These results are explained in terms of an ion‐trap mechanism subject to limitations on the partition coefficients of the acids and pos

ISSN:0031-613X    

DOI:10.1002/ps.2780170106

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe uptake and translocation of14C‐isoproturon (3‐p‐cumenyl‐1‐1,‐dimethylurea) in wheat (tolerant) and backgrass (sensitive) following foliar treatment under controlled environmental conditions were examined. The amount of14C‐isoproturon translocated through the xylem was about 10 times that translocated through the phloem in both wheat and blackgrass. However, 25.5% of the applied14C‐isoproturon was translocated in the xylem in blackgrass, compared with 8.9% in wheat.14C‐isoproturon did not respond significantly to induced sink‐demand in either species. Leaf‐disc autoradiograms revealed the absorption of14C‐isoproturon by the minor veins and translocation into the cut vein endings. No significant differences were found in between wheat and bla

ISSN:0031-613X    

DOI:10.1002/ps.2780170107

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0031-613X    

DOI:10.1002/ps.2780170108

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0031-613X    

DOI:10.1002/ps.2780170109

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0031-613X    

DOI:10.1002/ps.2780170101

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY