Bark beetles kill apparently vigorous conifers during epidemics by means of pheromone-mediated aggregation. During non-endemic conditions the beetles are limited to use trees with poor defense, like wind-thrown. To find olfactory cues that help beetles to distinguish between trees with strong or weak defense, we collected volatiles from the bark surface of healthy felled or standing Picea abies trees. Furthermore, living trees were treated with methyl jasmonate in order to induce defense responses. Volatiles were analyzed by combined gas chromatography and electroantennographic detection (GC-EAD) on Ips typographus antennae. Compounds eliciting antennal responses were characterized by single sensillum recording for identification of specific olfactory sensory neurons (OSN). Release of monoterpene hydrocarbons decreased, while oxygenated compounds increased, from spring to early summer in felled trees. In both beetle sexes particular strong EAD activity was elicited by trace amounts of terpene alcohols and ketones. 4-Thujanol gave a very strong response and the absolute configuration of the tested natural product was assigned to be (+)-trans-(1R,4S,5S)-thujanol by stereoselective synthesis and enantioselective gas chromatography. One type of OSN responded to all ketones and five other OSN were characterized by the type of compounds that elicited responses. Three new OSN classes were found. Of the eight EAD-active compounds found in methyl jasmonate-treated bark, the known anti-attractant 1,8-cineole was the one most strongly induced. Our data support the hypothesis that highly active oxygenated host volatiles could serve as positive or negative cues for host selection in I. typographus and in other bark beetles.
- MeSH
- acetáty farmakologie MeSH
- brouci fyziologie MeSH
- cyklopentany farmakologie MeSH
- elektrofyziologické jevy účinky léků MeSH
- kůra rostlin chemie účinky léků metabolismus MeSH
- monoterpeny chemická syntéza chemie farmakologie MeSH
- oxylipiny farmakologie MeSH
- plynová chromatografie s hmotnostně spektrometrickou detekcí MeSH
- smrk chemie metabolismus MeSH
- stereoizomerie MeSH
- styren chemie farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
Phenacoccus solenopsis is an economically important insect pest of different agronomic and horticultural field crops. In Pakistan, the cotton crop was severely attacked by P. solenopsis during 2007 and since then a varied group of insecticides are used by farmers to manage this pest. As a result, insecticide resistance has become a barrier in control of P. solenopsis. The current study was designed to explore the basics of genetics, realized heritability and possible genetic mechanisms of resistance against spirotetramat in P. solenopsis. Before selection, the wild population (Wild-Pop) showed 5.97-fold resistance when compared with lab-reared susceptible strain (Susceptible Lab-Pop). The P. solenopsis was selected with spirotetramat to 21 generations, called Spiro-SEL Pop, which showed 463.21-fold resistance as compared with the Susceptible Lab-Pop. The values of LC50 for F1 (Spiro-SEL Pop ♂ × Susceptible Lab-Pop ♀) and F1 (Spiro-SEL Pop ♀ × Susceptible Lab-Pop ♂) populations were statistically similar and values of dominance level were 0.42 and 0.54, respectively. Reciprocal crosses between Susceptible Lab-Pop and Spiro-SEL Pop showed that resistance was of autosomal in nature with incomplete dominant traits. According to the fit test, monogenic model estimation of the number of genes, which are responsible for the development of spirotetramat resistance in a population of P. solenopsis, showed that multiple genes are involved in controlling the resistance levels in tested strains of P. solenopsis. The value of heritability for resistance against spirotetramat was 0.13 in P. solenopsis. Our results suggested the presence of a metabolic-based resistance mechanism associated with the monooxygenases in P. solenopsis, while testing the synergism mechanism. These results will provide the baseline to design an effective control strategy to manage P. solenopsis in the field.
- MeSH
- aza sloučeniny farmakologie MeSH
- biotest MeSH
- Hemiptera účinky léků enzymologie metabolismus MeSH
- insekticidy farmakologie MeSH
- oxygenasy se smíšenou funkcí genetika metabolismus MeSH
- rezistence k insekticidům MeSH
- spirosloučeniny farmakologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Pákistán MeSH
The housefly, Musca domestica L. (Diptera: Muscidae), is a major medical and veterinary insect pest. It serves as a vector of many pathogenic microorganisms causing spoilage of food and diseases in human and animals. Use of chemical insecticides is adapted as a principal tool to manage housefly. Insecticides have many unforeseen ecological consequences including effects on non-target organisms. In the present study, we have assessed the effects of 10 different synthetic insecticides on the growth of mycoflora associated with the external body of the housefly by using poison food technique. Our results reveled that all synthetic insecticides enhanced the growth. Surprisingly, in most of the cases, mycelial growth of fungi was significantly increased at high concentration as compared with lower concentration. This study provides useful information about the dangerous effects of synthetic insecticides on environment by increasing the spread of various non-target pathogenic, mycotoxigenic, and food spoiling fungi, carried by houseflies.
- MeSH
- hmyz - vektory mikrobiologie MeSH
- houby klasifikace účinky léků růst a vývoj MeSH
- insekticidy farmakologie MeSH
- moucha domácí mikrobiologie MeSH
- společenstvo účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
The onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a polyphagous pest that causes serious damage to agricultural crops, vegetables, and ornamental plants worldwide. Farmers rely on the extensive usage of synthetic chemical insecticides to control T. tabaci. There is a dire need to develop alternative control strategies to overcome the problems posed by chemical insecticides. Efficient traps would allow sensitive monitoring and possibly mass trapping. A field experiment was conducted to evaluate the potential of three plant compounds with known release rates (ranging from 6-30 mg/d); eugenol (Eug), 1, 8-cineole (eucalyptol), and linalool in all possible combinations with a thrips attractant, ethyl iso-nicotinate (EI). A combination of EI with Eug increased the effect of EI by attracting 100% more thrips (effect size, 1.95) as compared to the control of EI alone. Catches in remaining treatments were lower and or not significantly different from EI alone. The results from our study could be used to develop improved volatile blends to be used for monitoring traps. Our data suggests that these traps could be effective even at very low populations.
- MeSH
- eugenol farmakologie MeSH
- feromony farmakologie MeSH
- kyseliny isonikotinové farmakologie MeSH
- monoterpeny farmakologie MeSH
- synergismus léků MeSH
- Thysanoptera účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
Mosquitoes are known to be vectors of numerous diseases leading to human morbidity and mortality at large scale in the world. Insecticide resistance has become a serious concern in controlling the insect vectors of public health importance. Dimethoate is an organophosphate insecticide used to control different insect pests including mosquitoes. Biological parameters of susceptible, unselected, and dimethoate-selected strains of Culex quinquefasciatus Say were studied in the laboratory to recognize resistance development potential and associated fitness cost. The dimethoate-selected strain showed 66.48-fold resistance to dimethoate compared with the susceptible strain after three continuous selections of generations. Realized heritability estimates of dimethoate resistance in Cx. quinquefasciatus yielded a value of 0.19. In dimethoate-selected strain, the biological traits including larval weight, survival from first instar to pupae, fecundity, number of next-generation larvae, relative fitness, net reproductive rate, intrinsic rate of natural increase, and biotic potential were significantly reduced as compared with the unselected strain. However, adult longevity, mean relative growth rate, weight of egg raft, female ratio, pupal duration, and emergence rate of the dimethoate-selected strain did not differ significantly compared with that of the unselected strain. This study provides useful information to devise retrospective management strategy for dimethoate resistance in Cx. quinquefasciatus.
- MeSH
- Culex účinky léků genetika růst a vývoj MeSH
- dědičnost * MeSH
- dimethoát farmakologie MeSH
- genetická zdatnost * MeSH
- insekticidy farmakologie MeSH
- kukla účinky léků genetika růst a vývoj MeSH
- larva účinky léků genetika růst a vývoj MeSH
- rezistence k insekticidům * MeSH
- selekce (genetika) * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
