bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long‐term effects of insecticides on diaeretiella rapae (m'intosh), a parasite of the cabbage aphid
Authors: El‐Ghar Gamal E. S. Abo , El‐Sayed Abd 
Published: November 2006

AbstractFive insecticides were tested in the laboratory for their selective activities between the cabbage aphid, Brevicoryne brassicae (L.), and its associated parasitoid, Diaeretiella rapae (M'Intosh). Based on the concentration/mortality regressions, the synthetic pyrethroids tralomethrin and cypermethrin were the most active insecticides against both the cabbage aphid and the parasitoids within the mummified aphids, whereas the carbamate methomyl was the least active. Selectivity ratios, at LC50, for B. brassicae vs. D. rapae in the mummified aphids showed that all insecticides tested were more active against B. brassicae than against the parasitoids. All insecticides used at the recommended field rates reduced the emergence of adult parasitoids from mummified aphids by 55–97% of that of control. Survival and longevity of emerged D. rapae were significantly reduced by all insecticides and rates used.Consequently, the latent effects of these insecticides applied at and below the recommended field rates were estimated on the parasitoids through two successive generations. The recommended rates used for both methomyl and cypermethrin reduced fecundity of D. rapae recorded at the F1‐generation by 75% of that of control. The emergence of F1‐progeny D. rapae was not significantly affected in any treatment, whereas the survival and longevity of adult parasitoids were reduced by most treatments.At the F2‐generation, the fecundity of parasitoid females was still lower than in the untreated control. Emergence and survival of adult parasitoids seemed to be slightly affected, whereas the adult longevity was highly affected in all treatments.Methomyl, tralomethrin and cypermethrin might be preferred because they had minimal adverse effects on emergence of parasitoids from the mummified aphids and their subsequent survival, longevity and fecundity, when applied at rates little below the recommended field rates.
Cytochrome P‐450 Inducers and Inhibitors Interfering with Ecdysone 20‐Monooxygenases and Their Activities during Postembryonic Development of Neobellieria bullata Parker
Authors: Darvas Béla , Rees Huw H. , Hoggard Nigel , El‐Din Mahmoud H. Tag , Kuwano Eiichi , Bélai Iván , Timár Tibor 
Published: November 2006

AbstractThe cytochrome P‐450‐dependent microsomal and mitochondrial ecdysone 20‐monooxygenase systems convert ecdysone into 20‐hydroxyecdysone. The microsomal fraction of fat bodies of zero h wandering stage fleshfly larvae (Neobellieria bullata; Diptera: Sarcophagidae) has a high ecdysone 20‐ monooxygenase activity. The effects of cytochrome P‐450 inhibitors were investigated in vitro on microsomal ecdysone 20‐monooxygenase. Metyrapone, fenarimol and certain imidazole derivatives (KK‐42, KK‐110, KK‐135 and PIM) are strong inhibitors. The IC50 value of KK‐110, which is the strongest inhibitor, is 2 × 10−7 M. A triazolyl and two cyclopropylamine derivatives have low activity. The activities of different NADPH‐cytochrome c (P‐450) reductase inhibitors were also assessed; diquat dibromide is a moderate inhibitor of microsomal ecdysone 20‐monooxygenase, while paraquat dichloride has no activity.In‐vivo experiments with cytochrome P‐450 inducers and inhibitors gave the following results: (a) fenarimol, FI‐121, precocene‐2 caused “permanent” first‐instar larvae; (b) barbital, phenobarbital and their sodium salts caused significant delay in larval development; (c) PIM, PTM, metyrapone, KK‐42, KK‐135, J‐2710, RH 5849 and colchicine caused moulting disturbances; (d) J‐2710, PIM, PTM, KK‐42, KK‐135, RH 5849 and colchicine caused lethal spiracle and mandible malformation; (e) KK‐110, fenarimol, barbital and phenobarbital caused precocious pupariation.
QSAR and Expert Systems in the Prediction of Biological Activity
Authors: Judson Philip N. 
Published: November 2006

AbstractTraditional quantitative structure‐activity relationship (QSAR) approaches and expert system approaches to the prediction of biological activity on the basis of chemical structure have concentrated on different aspects of the problem. The key aim of QSAR studies has been to create models that can predict activity–in a sense, to discover the rules that govern the relationships between the presence of structural features and biological activity. Expert systems developed in recent years, on the other hand, seek to apply rules that encompass existing human knowledge about the links between key, complex structural features and particular toxicological end‐points. It is now becoming possible to provide automated help with the discovery of rules that are suitable for use in the knowledge‐based expert systems. Some examples of this are discussed.
Effects of Ampropylfos (RS)‐1‐aminopropylphosphonic acid) on zoospore formation, repeated zoospore emergence and oospore formation in Aphanomyces spp.
Authors: Cerenius Lage , Rufelt Snorre , Söderhäll Kenneth 
Published: November 2006

AbstractThe effects on growth, asexual and sexual reproduction of different Aphanomyces species by the new fungicide ampropylfos ((RS)‐1‐aminopropylphosphonic acid) were tested using highly synchronized cultures. Ampropylfos reduced mycelial growth in Aphanomyces astaci, A. euteiches and A. stellatus. The fungicide was found to reduce zoospore numbers in all Aphanomyces species tested except A. euteiches. In one species, A. stellatus, zoospore production was inhibited at much lower fungicide concentrations than in the other species tested. In the pea pathogen A. euteiches, ampropylfos reduced the number of oospores, whereas the fungicide had little effect on asexual reproduction.
Analysis of foliar uptake of pesticides in barley leaves: Role of epicuticular waxes and compartmentation
Authors: Schreiber Lukas , Schönherr Jörg 
Published: November 2006

AbstractUptake of pesticides into barley leaves was measured under controlled conditions. Leaves detached from plants were submerged in aqueous solutions of 14C‐labelled (2,4‐dichlorophenoxy)acetic acid, triadimenol, bitertanol and pentachlorophenol. Uptake was biphasic. A short (30‐min) period with high rates of uptake was followed by uptake that proceeded more slowly and was steady over hours. Compartmentation of pesticides was studied by desorbing pentachlorophenol from leaves previously loaded with [14C]pentachlorophenol. From the uptake and desorption kinetics it was concluded that penetration of pesticides proceeds as follows: the compounds are first sorbed at the surface of epicuticular wax aggregates where they are in contact with the donor solutions. Solutes then diffuse through the surface wax aggregates into the cuticle. Equilibrium between donor solutions, surface wax and cuticle is established in about 30 min. After this time the amounts of solutes in these compartments no longer increase. Uptake after this time represents penetration into the leaf cells. This fraction of the pentachlorophenol is retained irreversibly, while that sorbed in wax and cutin can be desorbed again. All compounds were sorbed in cuticular waxes and partition coefficients wax/water were determined. On a mass basis only 5 to 10% of the amounts sorbed in cutin are sorbed in wax. This comparatively low solubility in wax contributes to the barrier properties of cuticular waxes. The other determinant of permeability is the very low mobility of solutes in cuticular waxes.
Synthesis, structure and herbicidal activity of pyrazol‐4‐yl alkyl ketone derivatives
Authors: McFadden Helen G. , Huppatz John L. , Couzens Michelle , Kennard Colin H. L. , Lynch Daniel E. 
Published: November 2006

AbstractNovel 5‐amino‐1‐phenylpyrazol‐4‐yl alkyl ketones were synthesised and their herbicidal properties evaluated. Active compounds in the series induced accumulation of protoporphyrin IX in etiolated cucumber cotyledons and caused light‐dependent herbicidal effects in 21‐day‐old cucumber plants. Structural features of the pyrazoles that contributed to herbicidal potency were found to be a high degree of halogen substitution in the 1‐phenyl ring, no substitution in the pyrazole 3‐position, and an ethyl group as the alkyl component of the ketone. The structure of 1‐[5‐amino‐1‐(2,4,6‐trichlorophenyl)pyrazol‐4‐yl]‐2‐methylpropan‐1‐one was determined by X‐ray crystallography.
Similarities in the antifungal activities of fenpiclonil, iprodione and tolclofos‐methyl against Botrytis cinerea and Fusarium nivale
Authors: Leroux Pierre , Lanen Catherine , Fritz René 
Published: November 2006

AbstractFenpiclonil [4‐(2,3‐dichlorophenyl)pyrrole‐3‐carbonitrile], a new agricultural fungicide, is a structural analogue of the antibiotic pyrrolnitrin used as an antimycotic in animals. Its spectrum of antifungal activity is similar to that of iprodione and tolclofos‐methyl, which are representatives of dicarboximide and aromatic hydrocarbon fungicides. Laboratory mutants of Botrytis cinerea and Fusarium nivale were simultaneously resistant to fenpiclonil, iprodione and tolclofos‐methyl and they showed an increased susceptibility to high osmotic pressure (sodium chloride, glucose). Strains of B. cinerea, collected in Champagne vineyards, which were resistant to dicarboximides were not resistant to fenpiclonil and tolclofos‐methyl. The antioxidant α‐tocopheryl acetate, and the cytochrome P‐450 inhibitors piperonyl butoxide and tebuconazole antagonized the fungitoxicity of fenpiclonil and iprodione in a wild‐type strain of B. cinerea. The uncoupling activity of fenpiclonil, iprodione and tolclofos‐methyl was detected in mitochondria from both a wild‐type strain and a laboratory mutant of B. cinerea. The concentrations effective towards this process were greater than those inhibiting the mycelial growth of wild‐type strains. These results suggest that fenpiclonil, iprodione, tolclofos‐methyl and related fungicides have the same biochemical mode of action. However, a primary effect on respiration, previously considered for pyrrolnitrin, seems to be improbable.
The susceptibility of a cereal aphid pest and its natural enemies to Deltamethrin
Authors: Wiles John A. , Jepson Paul C. 
Published: November 2006

AbstractThe intrinsic toxicity of deltamethrin to the grain aphid Sitobion avenae (F.) (Hemiptera: Aphididae) and a range of its important natural enemies was determined by laboratory topical bioassay. The natural enemies included polyphagous predators such as Pterostichus melanarius (Illiger), Harpalus rufipes (Degeer), Nebria brevicollis (F.), Agonum dorsale (Pont.), Demetrias atricapillus (L.), Trechus quadristriatus (Schrank), Bembidion obtusum (Serville), and B. lampros (Herbst.) (Coleoptera: Carabidae), Tachyporus hypnorum (F.) (Coleoptera: Staphylinidae) and Erigone atra (Blackwall) (Araneae: Linyphiidae), as well as the aphid‐specific ladybird Coccinella septempunctata (L.) (Coleoptera: Coccinellidae). Dose–response relationships were compared between species by probit analysis and maximum likelihood procedures to determine trends of susceptibility, measured in terms of ng a.i. arthropod−1 and μg a.i. g−1 body weight. The range of LD50 values varied between 0.8 and 232 ng arthropod−1 and 0.76 and 66.17 μg g−1 body weight for the species tested. The linyphiid spider E. atra (♀) was the most intrinsically susceptible species and had the narrowest tolerance distribution of the predators tested, whereas the small carabid beetle D. atricapillus was the least intrinsically susceptible predator species. There were significant differences in susceptibility between species of different orders, i.e. the Araneae, Hemiptera and Coleoptera. Differences within the Coleoptera were closely related to body weight, with the exception of the carabid beetle D. atricapillus, which seemed to be tolerant to deltamethrin. Knockdown time studies indicated that D. atricapillus had a higher survival rate after being knocked down than other species of predator. Aphid susceptibility per unit body weight was not significantly different from that of the predators. The aphid did, however, demonstrate a broader tolerance distribution than most of the predators, which may be related to its herbivorous nature. The use of laboratory susceptibility data to determine selectivity and to predict pesticide hazard is discussed.
Influence of organic matter and its clay complexes on metolachlor adsorption on soil
Authors: Pusino Alba , Liu Weiping , Gessa Carlo 
Published: November 2006

AbstractThe absorption of metolachlor, 2‐chloro‐6′‐ethyl‐N‐(2‐methoxy‐1‐methylethyl)acet‐o‐toluidide was studied on three soils of various physical and chemical properties. Adsorption isotherms conformed to the Freundlich equation. The kf values increased with increasing organic carbon content of the soils. However, variations in koc values by a factor of four were observed within three natural soils. For a given soil, the koc values remained essentially unchanged after lowering the carbon content by hydrogen peroxide oxidation. These results suggest that the contribution of organic matter to total metolachlor adsorption process is influenced by association mechanisms between organic and inorganic soil constituents. Studies with mixtures of clay and organic matter indicate that the interaction between the two soil components reduces the surfaces available for metolachlor adsorption.
Investigation of the possible vapour action of α‐endosulfan on Glossina morsitans morsitans
Authors: Smith Sandra C. 
Published: November 2006

AbstractAn all‐glass apparatus was set up whereby insects were brought into contact with α‐endosulfan vaporized from a heated bulb. The attribution of the initial high mortality to vapour action was not substantiated by subsequent chemical analysis. Use of reduced amounts of x‐endosulfan to provide more nearly the calculated saturated vapour concentration resulted in little kill. The α‐endosulfan vaporized transiently then condensed onto the surrounding surfaces; any mortality resulted from contact action. These observations do not support the contention that α‐endosulfan acts via the vapour phase at long range in the field.
Chemicals in integrated control
Authors: Oomen Pieter A. 
Published: November 2006

AbstractThe objective of Integrated Control (IC) is to provide economic and competitive cropping with as few undesirable effects of crop‐protection measures on the environment, the user or the consumer as possible. A general scheme of relevant variables, characteristics and their interrelationships is defined and those relations and aspects critical for realising the objective are identified. Particular attention is given to the function of pesticides and their adverse effects on beneficial organisms.Chemical control is least preferred of all effective measures because of possible undesirable effects. Nevertheless, chemical and biological measures are very much complementary and there is no reason to expect a major change in this situation.Apart from the general requirements for environmental, user and consumer safety, pesticides for use in IC schemes should be effective against target organisms but (largely) harmless to the beneficial organisms used in the biological measures, i.e. intrinsically selective or suitable for selective application. Because different profiles of pesticides are required to cover the needs of IC, the availability of a number of different pesticides and, especially, reliable information on their activity spectra is important.The need for, and development of, a database covering all possible effective measures for crop protection which might fill this need in The Netherlands, as an aid to scientists developing schemes for integrated control and for extensionists advising growers, is presented as a solution to the main constraint identified for IC in protected and other crops.
Novel approaches to integrated pest and disease control in glasshouse vegetables in the Netherlands
Authors: Van Steekelenburg Nico A. M. 
Published: November 2006

AbstractAs a result of government policy and consumers' attitudes to environmentally compatible growing systems, research is focused on reduction of pesticide input into the environment. This aim is approached in different ways.With so‐called “closed growing systems”, soil fumigants are no longer needed, resulting in an estimated 60% reduction in the total use of pesticides. Further, far smaller quantities of (systemic) pesticides need to be added to plants, via the nutrient solution, than with soil‐grown crops. Water disinfestation is essential to minimize the spread of diseases and heat treatment and ozonization are already used under commercial conditions. Filtration appears to be neither reliable nor practical. Other disinfestation methods are under investigation.Ventilators may be provided with insect‐proof screens to minimize infection pressure, especially on young plant material. Air filters in combination with mechanical ventilation may be an option for the future to raise healthy plants.A further reduction in the use of pesticides can be achieved by developing biological and integrated control of insects and fungi. Simultaneous application of several biocontrol methods in the fruit vegetable area has increased the complexity of IPM. Open rearing systems of parasitoids on alternative hosts to control cotton aphids and leaf miners are promising. IPM is highly dependent on the availability of selective chemicals.Biological control of root‐infecting fungi in substrate crops shows promise. Integrated control of powdery mildew in cucumbers using a combination of nutritional and climatic management and varieties showing partial resistance will be studied.Improvement of application techniques for pesticides is being studied by plant pathologists in cooperation with technical experts. The aim is to reduce pesticide application rates, to minimize losses to the environment and to avoid health risks for the worker.By developing decision‐support systems for crop protection, optimal use of beneficial insects is achieved and unnecessary applications of chemicals are avoided. A programme to develop such a system for the sweet pepper crop is under way.
IPM in protected crops: Concerns, challenges and opportunities
Authors: Van Oosten Henk J. 
Published: November 2006

AbstractThe Dutch government has a coherent, long‐term policy regarding attainment of a sustainable development affecting agriculture and horticulture, the requirements of which are very strict and will be difficult to satisfy. The growers of protected crops try to meet these requirements by developing so‐called closed growing systems. Two other approaches in the policy are a substantial reduction of the volume of pesticides used and a very critical evaluation of the pesticides permitted. In this governmental policy, Integrated Pest Management has shown prospects in horticulture; it will play a very important role in the near future but is now considered as part of the broader concept of Integrated Production Systems.The glasshouse industry is very actively developing its own strategy to satisfy government targets and market demands for high‐quality products produced by environmentally safe methods. The vegetable auctions have developed a policy of environmentally conscious production which should put the vegetable industry into a strong marketing position for its produce.
Control of seedborne pathogens and diseases of soybean seeds and seedlings
Authors: Sinclair James B. 
Published: November 2006

AbstractThe control of pathogens, including two bacteria, nine fungi and a virus that cause diseases of soybean seeds and seedlings is discussed. Control methods include general management practices, biocontrol agents, fungicides applied to seeds and foliage, and thermotherapy. Guidelines for the use of seed treatment and foliar fungicides are given. The fungicides commonly used are listed and the interaction between certain fungicides and Bradyrhizobium inoculant is discussed.
The fate and insecticidal activity of pirimiphos‐methyl in stored wheat grain
Authors: Matthews Wendy A. , Maliphant Paula 
Published: November 2006

AbstractThe degradation of [14C]pirimiphos‐methyl was investigated on a 1‐kg bulk of grain stored in the laboratory at 15°C for 28 weeks. Breakdown of pirimiphos‐methyl was slow, leaving 77% of the applied dose unchanged at the end of the experiment. The major degradation product was the hydroxypyrimidine (up to 12.5% of the applied dose) with the remainder of the residue (up to 12.1%) remaining within the grain tissues after solvent extraction. The efficacy of the treatment was assessed in a parallel experiment by bioassay of a 5‐kg bulk of grain dosed with unlabelled pirimiphos‐methyl. 100% Mortality of an organophosphateresistant strain of Oryzaephilus surinamensis L. was maintained throughout the experiment whereas some survival of an organophosphate‐resistant strain of Tribolium castanewm (Herbst) occurred after 12 weeks of storage. This increased to give a 20% survival rate at the end of the experiment.
Interaction between optical isomerism and plant pharmacological action, change of modes of action and chirality of 1‐(α‐methylbenzyl)‐3‐p‐tolylurea
Authors: Omokawa Hiroyoshi , Kawata Yoshinori , Konnai Makoto 
Published: November 2006

AbstractThe optical isomers, (R)‐1(α‐methylbenzyl)‐3‐p‐tolylurea ((R)‐MBU) and (S)‐1‐(α‐methylbenzyl)‐3‐p‐tolylurea ((S)MBU), which are analogues of daimuron [1‐(α,α‐dimethylbenzyl)‐3‐p‐tolylurea], a herbicide for Cyperaceae weeds and a safener for paddy rice, exhibited different biological responses. These two physiological properties of daimuron were observed separately in (R)‐MBU and (S)‐MBU. Only (R)‐MBU had herbicidal activity against Cyperaceae weeds, while the (S)‐isomer was a more effective safener against bensulfuron‐methyl (BSM) injury of rice seedlings than was (R)‐MBU. (S)‐MBU promoted root growth of rice seedlings, but the (R)‐enantiomer inhibited root growth. (S)‐MBU was a more potent inhibitor than (R)‐MBU on PS II reaction of spinach broken chloroplasts. Furthermore, (S)‐MBU and (R)‐MBU showed cross intergenus selective phytotoxicity among the Gramineae plants, Oryza sativa L. (rice, cv. Tsukinohikari, japonica), Triticum aestivum L. (wheat, cv. Norin No. 61) and Echinochloa crusgalli var. frumentacea Wight, on root growth inhibition in the dark.