Home About us Contact
|
Home About us Contact | ||
|
|
||
G Active Ingredient (g + active_ingredient)
Selected AbstractsPhytotoxicity assay for seed production using Brassica rapa L.INTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 4 2010David Olszyk Abstract Although pesticide drift can affect crop yield adversely, current plant testing protocols emphasize only the potential impacts on vegetative plant growth. The present study was conducted to determine whether a plant species with a short life cycle, such as Brassica rapa L. Wisconsin Fast Plants®, can be used to indicate potential effects on seed production of herbicides applied at relatively low levels (e.g., low field application rates [FAR]). The effects of ,0.1,×,FAR of aminopyralid, cloransulam, glyphosate, primisulfuron, or sulfometuron applied 14 d after emergence (DAE), were evaluated for B. rapa grown in mineral soil in pots under greenhouse conditions. Effects were expressed as the effective concentration of the herbicide producing a 25% reduction in a response (EC25) based on nonlinear regression. Brassica rapa seed dry weight was reduced by sulfometuron at an EC25 of 0.00014,×,a field application rate (FAR) of 53,g active ingredient (a.i.) ha,1, primisulfuron at 0.008 (experiment 1) or 0.0050 (experiment 2),×,FAR of 40,g,a.i.,ha,1, cloransulam at 0.022,×,FAR of 18,g,a.i.,ha,1, glyphosate at 0.0399,×,FAR of 834,g,a.i.,ha,1, and by aminopyralid at 0.005,×,FAR of 123,g,a.i.,ha,1, but only for 1 of 2 experiments. Reduced seed production occurred at less than the FAR that reduced shoot dry weight with sulfometuron and primisulfuron, whereas neither aminopyralid, cloransulam, nor glyphosate affected shoot dry weight. A short life cycle form of B. rapa could be used to indicate reduced seed production with plants grown only 1 week longer (,35,DAE) than as the current vegetative vigor test for nontarget herbicide effects on plants. Integr Environ Assess Manag 2010;6:725,734. © 2010 SETAC [source] Short-term assessment of dung beetle response to carbosulfan treatment against desert locust in SudanJOURNAL OF APPLIED ENTOMOLOGY, Issue 8 2009H. Eriksson Abstract The beneficial role of dung beetles (Coleoptera: Scarabaeidae) is well known. Potential risks to these beetles from the widespread use of insecticides against the desert locust, a significant plant pest in Africa, the Near East and South West Asia, have not been studied previously. Short-term responses of dung beetles to carbamate carbosulfan (Marshal®, ultra low-volume formulation, 100 g active ingredient ha,1) were assessed during desert locust control operations at five sites within two major biotopes: Acacia tortilis shrubland and cultivated wetland; on the Red Sea Coast of Sudan. The study took place during January,February 2004. At each site, fresh dung from Zebu cows was placed in areas targeted for desert locust control. Dung pats were placed in plots in two areas and left for 24 h, before and after insecticide application. Beetles were extracted by floatation. There was a significant decrease in abundance between the pre- and post-spray period in treated areas for the Scarabaeinae species Onthophagus margaritifer (a dark colour morph). In contrast, it was found that Aphodius lucidus and beetles at the subfamily level of Aphodiinae increased in numbers after insecticide treatment. Mortality and sublethal impacts as well as a repellent effect of the insecticide may explain the decrease in Onthophagus margaritifer, while the increase in Aphodiinae beetles could be an indirect response to lower numbers of Scarabaeinae beetles in competing for the same resource. These organisms and the applied methodology may be useful for environmental monitoring of desert locust control, thus further studies are suggested. The assessment also revealed a marked difference between the two biotopes with high abundance and species richness of dung beetles in A. tortilis shrubland, while these measures were low in the cultivated wetland. Five new species of dung beetles for Sudan were found in this study. [source] Orientational disruption of codling moth, Cydia pomonella (L.) (Lep., Tortricidae), by concentrated formulations of microencapsulated pheromone in flight tunnel assaysJOURNAL OF APPLIED ENTOMOLOGY, Issue 9-10 2005L. L. Stelinski Abstract:, The effects of two formulations of microencapsulated pheromone (CheckMate CM-F), containing 14.3% (E,E)-8,10-dodecadien-1-ol (codlemone), on the behaviour of the male codling moth, Cydia pomonella (L.), were evaluated in a flight tunnel after several periods of formulation ageing. The two treatments of CheckMate CM-F evaluated consisted of the label-recommended field rate of 50 g active ingredient (a.i.)/ha diluted in: (1) a standard 1000 l of water (low concentration 0.05 g/l), and (2) a low volume of 100 l of water (high concentration 0.5 g/l). The low-concentration treatment was formulated by diluting 0.071 ml of CheckMate CM-F in 500 ml of water and the high-concentration treatment contained 0.71 ml of CheckMate CM-F in 500 ml of water. Wax-paper strips (2.1 × 20 cm) were treated at 0.06 ml of solution/cm2. The mean (±SE) number of CheckMate CM-F microcapsules adhering to treated wax-paper strips in the high-concentration treatment (398 ± 38) was sevenfold greater than that (57 ± 5) counted on wax-paper strips treated with the low concentration. Both low- and high-concentration treatments prevented anemotactic orientation of male codling to an adjacent 0.1 mg codlemone lure for up to 24 h after application. These moths flew out of the release cages, but exhibited erratic and short flights not restricted to any plume and ending at the tunnel walls or the floor. This occurred with approximately 60 and 400 microcapsules per wax-paper strip in the low- and high-concentration treatments, releasing codlemone at approximately 0.15 and 1.5 ,g/h respectively. After 2 days of ageing, the low-concentration treatment no longer interfered with the ability of males to find the codlemone lure. However, the number of males contacting the lure was significantly reduced for up to 6 days with the high-concentration treatment relative to the control and low-concentration treatments. The high-concentration treatment no longer impeded normal orientational flight after 2,6 days of ageing; but, it diverted males from the codlemone lure by causing them to land on the adjacent treated wax-paper strips. This occurred at a release rate of approximately 0.7 ,g codlemone/h from approximately 400 microcapsules per wax-paper strip distributed as clumps of approximately 30 microcapsules per 14 mm2. We suggest that an initial but short-lived disruption mechanism like camouflage is followed by a longer period of false-plume following to clumps of microcapsules. The low-volume, concentrated application method for disseminating pheromone microcapsules warrants further investigation for moth codling, as well as other pests because this approach may improve the efficacy without the need for increasing the field application rate. [source] Effect of triflumuron on brood development and colony survival of free-flying honeybee, Apis mellifera L.JOURNAL OF APPLIED ENTOMOLOGY, Issue 4 2004O. G. Amir Abstract:, The effect of the insect growth regulator (IGR) triflumuron (Alsystin® 25 WP) on honeybee, Apis mellifera L. (Hym., Apidae), was studied in a semi-field test. Free-living colonies were fed one litre per hive of sucrose syrup containing 0, 0.025, 0.25 or 2.5 g of triflumuron. A significant reduction in flight activity was noted 6,10 weeks post-treatment at the two higher doses. These colonies reared less brood than before treatment. While the comb area occupied by uncapped brood was as high as [0.025 and 0.25 g active ingredient (a.i.)] or higher (2.5 g a.i.) than before treatment, there was a significant decline in capped brood at the two higher doses, indicating enhanced larval mortality. No capped brood was reared in the hive treated at the highest dose from 3,9 weeks post-treatment. Yet there was a significant accumulation of pollen and honey in the brood compartment at all doses. All colonies except the one treated at the highest dose survived the following winter. However, at 43 weeks post-treatment, hives treated at intermediate and low doses showed a significant increase in uncapped brood and a significant decrease in capped brood. This study revealed a strong residual toxicity of triflumuron to brood and substantiated its classification as hazardous to honeybee. [source] Identification and Regulation of Genes from a Biocontrol Strain of Fusarium oxysporumJOURNAL OF PHYTOPATHOLOGY, Issue 9 2007D. R. Fravel Abstract Differential display with three time points revealed that thiram altered expression of numerous genes in the biocontrol fungus Fusarium oxysporum CS-20. Of the 101 bands purified from the differential display gel, 86 were successfully cloned, and 64 sequenced. Based on nucleic acid sequences, homology to known products was found using BLASTn for 26 sequences and homology to hypothetical proteins was found for six sequences, also from Gibberella zeae. One band (BM1 24-1) showed homology to an ABC transporter from three different fungi. Because of its association with detoxification functions, the ABC transporter was selected for further study. Mycelia of CS-20 were exposed to 25 ,g active ingredient (a.i.) thiram in liquid culture for various times from 0 to 8 h. Quantitative real-time PCR was used to evaluate gene expression. At 30 min after treatment with thiram, the ABC transporter was upregulated 20- to 25-fold relative to the control treatment. The ABC transporter was upregulated 15-fold at 1 h after treatment and 10-fold at 2 h. At 8 h after treatment, there was no difference between treated and non-treated for expression of the ABC transporter. Transcription of the gene encoding EST BM1 24-1 is induced in response to thiram treatment and may function in providing resistance in F. oxysporum isolate CS-20 to fungicides and other toxins. Tolerance to toxins may be critical to the successful inclusion of CS-20 in disease control strategies in cropping systems. [source] Variation of Fungicide Resistance in Czech Populations of Pseudoperonospora cubensisJOURNAL OF PHYTOPATHOLOGY, Issue 3 2007J. Urban Abstract During the growing seasons between the years 2001 and 2004, 98 isolates of Pseudoperonospora cubensis from nine regions of Czech Republic were collected and screened for tolerance/resistance to the three frequently used fungicides (propamocarb, fosetyl-Al, metalaxyl). Fungicides were tested in five different concentrations, using a floating disc bioassay. Fungicide effectiveness varied considerably. Propamocarb appeared most effective and all the isolates collected in the years 2001,2003 were found sensitive to all tested concentrations [607,9712 ,g active ingredient (a.i.)/ml]. In 2004, some strains with increased resistance to propamocarb were detected. These strains were characterized by tolerance at the lowest concentrations (607 ,g a.i./ml, eventually on 1214 ,g a.i./ml); however, they were controlled by 2428 ,g a.i./ml. Fosetyl-Al was effective at the recommended concentration of 1600 ,g a.i./ml against all isolates. However, the occurrence of isolates (collected in 2001) which sporulated at low concentrations (400 and 800 ,g a.i./ml) indicated that the selection for tolerance occurs in the pathogen population. Nevertheless, this phenomenon was not confirmed with the P. cubensis isolates collected between the years 2002 and 2004. Metalaxyl was found ineffective, because 97% of the isolates showed the resistance to the recommended concentration (200 ,g a.i./ml), and the other 3% of isolates expressed tolerant response. The majority of the isolates showed profuse and/or limited sporulation at higher concentrations (400 and 800 ,g a.i./ml). A substantial shift to highly metalaxyl resistant strains was evident in the Czech P. cubensis populations during 2001,2004. [source] | ||||||||||