Prognose-Modell zur Erfassung des Rückstandsverhaltens von Metribuzin und Methabenzthiazuron im Boden und deren Auswirkungen auf Folgekulturen

A predictive model for the assessment of metribuzin and methabenzthiazuron residues in soil and their effects on succeeding crops Aus der simulierten Abbaukurve lassen sich somit für jeden beliebigen Zeitraum nach Applikation eines Herbizids die maximalen pflanzenverfügbaren Wirkstoffanteile ableiten, aus denen die Auswirkungen auf mögliche Folgekulturen prognostiziert wurden. Die relative Empfindlichkeit (im Bereich der ED₅₀) der untersuchten Kulturpflanzen in Hydroponik war bei Metribuzin: Möhre < Bohne = Salat < Erbse = Spinat und bei MBT: Bohne = Erbse = Salat < Spinat = Möhre. Weiterhin konnte gezeigt werden, dass unter Labor- und Freilandbedingungen evtl. auftretende Schäden in fast allen Fällen in den gleichen Aktivitäskategorien lagen. The degradation of the herbicides metribuzin and methabenzthiazuron (MBT) was simulated under outdoor conditions in a sandy soil by a computer model based on the dominating influence of temperature and moisture on degradation, which is measured in preceding laboratory experiments. Depending on the conditions of incubation (10–30°C, 20–90% water holding capacity) the half-life of metribuzin was 11–60 days and of MBT 42 > 1200 days. Knowing the plant available soil water, the fraction of a total herbicide residue potentially available to plants can be calculated from the distribution coefficient (K_d-value). In the soil under investigation, for metribuzin 77% and for MBT 16% of the total residue was available to plants. Thus, the maximum residue available to plants can be calculated from the simulated degradation curve for any period after the application of a herbicide and in combination with a predictive model the effect on succeeding crops can be predicted. The specific susceptibility of the crops in question has to be established in preceding hydroponic culture experiments. The relative susceptibility (about ED₅₀) of the plants in hydroponic-culture was earrot相似文献   

Zur Ausbreitung des Eukalyptusbohrers,Phoracantha semipunctata (F.), im Mediterranraum und auf den Kanarischen Inseln (Coleoptera: Cerambycidae)

It is shown how the Longhorn BeetlePh. semipunctata was introduced in the East and has penetrated in about five phases great parts of the Mediterranean Basin and the Canary Islands. The exact way of invasion is not clearly defined. The possibilities of introduction are discussed. The occurrence ofPh. semipunctata in Libya and at Gomera is new. Host plants and one hitherto known parasitoid and one predator are indicated in this part of the areal of the species.      

Untersuchungen Zum Einfluss einer Pflanzenscutzmittelspritzfolge auf das Rückstandsverhalten von Terbutryn und die mikrobielle Aktivität im Boden. Teil I. Rückstandsverhalten von Terbutryn

Studies on the effect of a pesticides spray sequence on the behaviour of terbutryn residues and on soil microbial activity. Part I. Behaviour of terbutryn residues In laboratory incubation studies (at 10 and 20°C and 30 and 60% soil water-holding capacity) terbutryn dissipated with half lives of 19–113 days at a standard rate of application (2·09 or 2·8mg kg^?1) and 62–258 days at a 10-fold higher rate. There was little difference between two soils of different sorptive properties. The water-extractable residues showed that terbutryn was extensively adsorbed by both soils with only 12–18%‘plant-available'. Persistence of terbutryn in the field was consistent with the laboratory results and was predicted satisfactorily with a mathematical simulation model. In the laboratory, terbutryn breakdown was inhibited by the simultaneous application of dinoseb acetate and stimulated by triadimefon and parathion but these results were not confirmed in the field.     

Untersuchungen zum Einfluss einer Pflanzenschutzmittelspritzfolge auf das Rückstandsverhalten von Terbutryn und die mikrobielle Aktivität im Boden. Teil II. Beeinflussung der mikrobiellen Aktivität

Studies on the effect of a pesticide spray sequence on the behaviour of terbutryn residues and on soil microbial activity. Part II. Influence on microbial activity In laboratory incubation experiments (at 10 and 20°C and 30 and 60% soil water-holding capacity) soil microbial activities (dehydrogenase, respiration after glucose amendment and nitrogen transformations) were scarcely affected by 20·9 and 28·0 mg kg^?1, respectively, of terbutryn in two soils of different sorption properties. In contrast, dinosebacetate, alone or mixed with terbulryn, triadimefon or parathion, inhibited dehydrogenase activity and respiration even at a low rate of application (2·87 mg kg^?1). Following application of a 10 times higher rate to a highly adsorbent soil there was an initial inhibition of nitrification followed by an enhanced rate of nitrogen mineralization. Triadimefon and parathion, alone and in combination with other pesticides, caused both stimulation and inhibition of microbial activity; the reason is not clear. The effects on dehydrogenase and respiration were confirmed in field experiments. Dehydrogenase activity was the most sensitive and so could be a useful test for the side-effects of pesticides on soil micro-organisms. Additional work on nitrogen transformations is needed to interpret the results.     

über die Wirkung von Steinkleekraut und Patschuli?lgranulat auf die KleidermotteTineola bisselliella Hum. (Lepidoptera: Tineidae)

In Wahl- und Zwangsversuchen wurde die Wirkung des Steinkleekrautes (Melilotus officinalis [L.] Pall.) und des Ölgranulates der Patschulipflanze (Pogostemon patchouly Pellet.) auf die KleidermotteTineola bisselliella Hum. untersucht. Patschuliölgranulat zeigte sowohl repellierende als auch abtötende Wirkung. Die Befallsintensität an Wollstoffproben wurde dadurch stark reduziert. Steinkleekraut zeigte nur eine kurzfristig abschreckende Wirkung auf die Falter. Längerfristig führte es dahingegen eher zu verstärktem Befall an den Wollstoffproben.Free-choice chamber- and compulsory-tests were carried out to investigate the effect of sweet clover leaves (Melilotus officinalis [L.] Pall.) and the granulated oil extract of the patchouli-plant (Pogostemon patchouly Pellet.) on the webbing clothes mothTineola bisselliella Hum. Granular patchouli oil was found to be both, repellent and toxic. Thus the intensity of infestation on woolen fabric samples had been reduced largely. Sweet clover leaves showed only a short-term repellent effect on the adults, whereas in long-term experiments an increase in infestation was found.

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Red Oak Borer, Enaphalodes rufulus (Coleoptera: Cerambycidae), in the Ozark Mountains of Arkansas, U.S.A.: An Unexpected and Remarkable Forest Disturbance

A complex interaction of multiple factors has resulted in an oak decline event in oak-hickory forests of the Ozark Mountains of Arkansas and Missouri, U.S.A. The most striking feature of this situation is an unprecedented population explosion of red oak borer, a species of cerambycid beetle, Enaphalodes rufulus (Haldeman), which appears to be causing extensive mortality to mature red oaks (Quercus, subgenus Erythrobalanus). The insect is a native species, historically a minor pest of oaks, found throughout the eastern United States. Beetles normally reproduce in living oaks, as larvae initially feed in phloem tissue and subsequently bore into xylem where pupation occurs. The life cycle is two years in length and synchronous adult emergence occurs in odd-numbered years. Data from previous research indicate average attack densities of less than four per tree with a high of 71 on a single tree. Historical emergence densities are similarly low and the highest reported was 15 adults from one tree. Our research is concerned with understanding factors contributing to this outbreak; developing sampling methods for red oak borer; assessing oak mortality; and evaluating site and stand conditions associated with the current outbreak. Results of our initial sampling reveal dramatically higher average attack densities of 244 per m2 and emergence densities of 18 per m2 of bark surface area. We confirm a three-week period of adult emergence and activity during mid-June to early July. We also report on possible management responses by federal and state agencies to this remarkable epidemic and oak mortality crisis.     

Impact of Cry3Bb1-expressing Bt maize on adults of the western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

BACKGROUND: Genetically engineered maize producing insecticidal Cry3Bb1 protein from Bacillus thuringiensis (Bt) is protected from root damage by corn rootworm larvae. An examination was made to establish whether western corn rootworm (Diabrotica virgifera virgifera) adults are affected by Cry3Bb1‐expressing maize (MON88017) when feeding on above‐ground tissue. RESULTS: In laboratory bioassays, adult D. v. virgifera were fed for 7 weeks with silk, leaves or pollen from Bt maize or the corresponding near‐isoline. Male, but not female, survival was reduced in the Bt‐leaf treatment compared with the control. Female weight was lower when fed Bt maize, and egg production was reduced in the Bt‐silk treatment. ELISA measurements demonstrated that beetles feeding on silk were exposed to higher Cry3Bb1 concentrations than beetles collected from Bt‐maize fields in the United States. In contrast to silk and pollen, feeding on leaves resulted in high mortality and low fecundity. Females feeding on pollen produced more eggs than on silk. C:N ratios indicated that silk does not provide enough nitrogen for optimal egg production. CONCLUSIONS: Direct effects of Cry3Bb1 on adult beetles could explain the observed effects, but varietal differences between Bt and control maize are also possible. The impact of Bt maize on adult populations, however, is likely to be limited. Copyright © 2011 Society of Chemical Industry     

Effects of diflubenzuron on the pupal-adult development of Tenebrio molitor L. (Coleoptera,Tenebrionidae): Growth and development,cuticle secretion,epidermal cell density,and DNA synthesis

Diflubenzuron (DFB), applied by dipping on newly emerged pupae of Tenebrio molitor L., disturbs the pupal-adult development. Four main types of treated insects were obtained according to external morphology: blocked pupae, adults unable to ecdyse, adults partially ecdysed, and adults completely ecdysed. The proportion of these four types varied with the time of treatment during the pupal life. When DFB was administered by dipping at a 10 g/liter concentration to newly emerged pupae, HPLC measurements showed that the different responses were due to a difference in the levels actually incorporated. Histological and ultrastructural observations of sternal cuticles revealed that DFB disturbs the cuticle deposition: reduction of its thickness and modifications of its architecture. Tritiated thymidine incorporation and cell density measurements in sternal epidermis show that DFB affects both mitoses and DNA synthesis in blocked pupae. These findings suggest that DFB interferes with other biochemical processes besides the chitin biosynthesis; whether these effects are primary or secondary remain to be determined.     

The fungicidal activity of substituted 1, 4-naphthoquinones. Part 1: Alkylthio and arylthio derivatives

Some symmetrical and unsymmetrical 2, 3-bis(arylthio)-1, 4-naphthoquinones have been synthesised and assayed against Botrytis cinerea, Cladosporium fulvum and Venturia inaequalis. With the surprising exception of the 2, 3-bis(4-chlorophenylthio) derivative, the compounds were essentially inactive. The 2-phenylthio and lower 2-alkylthio derivatives showed a high level of activity, which was absent in the 2-pentylthio and higher homologues.     

滞育七星瓢虫酰基辅酶AΔ11去饱和酶基因的克隆及表达分析

去饱和酶（Fatty acid desaturase,FAD）是生物体不饱和脂肪酸合成中的关键酶,酰基辅酶AΔ11去饱和酶基因是其中重要的一种。本试验基于七星瓢虫Coccinella septempunctata L.转录组数据,利用RT-PCR和RACE技术从滞育七星瓢虫中克隆得到酰基辅酶AΔ11去饱和酶基因全长,并命名为CsFadΔ11（GenBank登录号：MF458996）,该基因全长1447 bp,开放阅读框（ORF）1095 bp,编码364个氨基酸,预测蛋白质分子量为42.99 kD,等电点（pI）为8.87,无信号肽。氨基酸序列分析结果表明,CsFadΔ11有3个组氨酸富集区和6个跨膜结构域,与膜翅目的内华达古白蚁Zootermopsis nevadensis同源性较高。利用实时荧光定量PCR技术研究其时间表达模式,发现CsFadΔ11基因在七星瓢虫初羽化、滞育诱导10 d、滞育诱导20 d、滞育初期、滞育后期、滞育解除期以及正常发育状态下均有所表达,且在滞育早期表达量最高,其次是在滞育解除个体中。其整体表达趋势与相应时期脂积累变化情况基本相符,推测CsFadΔ11基因参与七星瓢虫脂积累调控,并进一步影响七星瓢虫滞育。     

Comparative repellent activity of single,binary and ternary combinations of plant essential oils and their major components against Sitophilus oryzae L. (Coleoptera: Curculionidae)

Journal of Plant Diseases and Protection - In the present study, repellent activity of three plant essential oils (EOs) [anise (Pimpinella anisum&nbsp;L.), eucalyptus (Eucalyptus camaldulensis...     

Effects of Artemisia annua L. (Asteracea) on nutritional physiology and enzyme activities of elm leaf beetle, Xanthogaleruca luteola Mull. (Coleoptera: Chrysomellidae)

Methanolic extract of Artemisia annua L., a weed collected around paddy fields in north of Iran, was investigated for its toxic effects on: feeding, growth, fecundity, fertility including the biochemical characteristics of elm leaf beetle Xanthogaleruca luteola Mull. The toxicity tests indicate that insecticidal effect was 2.4-fold higher in 3rd instar larvae than in adults. The LC₅₀ was 48% and 43.77% of a methanolic leaf extract at 24 and 48 h, respectively. The feeding deterrence was highest at 10% concentration and lowest at 0.625% for 3rd instar larvae and adults during the first 24 h and decreased thereafter. Larval duration significantly increased at higher concentrations. Larval treatment with 10% methanolic extract resulted in deformed adults (adultoids) with drastic changes in gross morphology of female reproductive system. Food digestion and assimilation significantly decreased in adults. Larval duration and adult fecundity and fertility were also significantly reduced. Twenty-four hours after treating 3rd instar larva with the extract the levels of glucose, protein, urea, uric acid, α-amylase, alkaline phosphatase, alanine amino transferase and aspartate amino transferase significantly changed. However, at 48 h the extract lost its potency. The extract did not effect the level of cholesterol in treated larva. These results indicate that Artemisia annua L. extract contains inhibitors of key metabolic pathways that may be useful in future control of the elm leaf beetle.