Effects of the invasive plant Xanthium strumarium on diversity of native plant species: A competitive analysis approach in North and Northeast China.

Xanthium strumarium is native to North America and now has become one of the invasive alien species (IAS) in China. In order to detect the effects of the invader on biodiversity and evaluate its suitable habitats and ecological distribution, we investigated the abundance, relative abundance, diversity indices, and the number of the invasive and native plants in paired invaded and non-invaded quadrats in four locations in North and Northeast China. We also analyzed the effects of monthly mean maximum and minimum temperatures, relative humidity (%), and precipitations (mm). Strong positive significant (P < 0.01) correlation and maximum interspecific competition (41%) were found in Huailai between invaded and non-invaded quadrats. Shannon's Diversity Index showed that non-invaded plots had significantly (P < 0.05) more diversified species than invaded ones. The significant (P < 0.05) Margalef's Richness Index was found in Huailai and Zhangjiakou in non-invaded recorded heterogeneous nature of plant communities. Similarly, significant (P < 0.05) species richness found in Huailai and Zhangjiakou in non-invaded quadrats compared to invaded ones. Maximum evenness of Setaria feberi (0.47, 0.37), Seteria viridis (0.43) found in Fushun and Zhangjiakou recorded more stable in a community compared to other localities. Evenness showed positive relationship of Shannon Entropy within different plant species. The higher dissimilarity in plant communities found in Huailai (87.06%) followed by Yangyuan (44.43%), Zhangjiakou (40.13%) and Fushun (29.02%). The significant (P < 0.01) value of global statistics R (0.943/94.3%) showed high species diversity recorded in Huailai followed by Zhangjiakou recorded by non-metric multidimensional scaling and analysis of similarity between invaded and non-invaded plots. At the end it was concluded that the diversity indices reduced significantly (P < 0.05) in invaded quadrats indicated that native plant species become less diverse due to X. strumarium invasion. The degrees of X. strumarium invasion affected on species richness resulted to reduce diversity indices significantly in invaded quadrats.

Species diversity of different insect families trapped under beer-based volatile fermentation.

BACKGROUND: Insect species composition is an important phenomenon playing a significant role in the ecosystem. Chemical control of insects and pests releases toxic materials to the environment. These chemicals are dangerous to human populations. In this situation, there is a dire need to develop strategies to overcome the haphazard use of chemicals. The present investigations were carried out to explore the diversity of different insects attracted through bait fermentation. METHODS: The traditionally prepared bait fermentation was used to attract different insect populations both in treated (traps installed near field crops) and control traps (traps installed near invasive weed). Abundance, evenness, richness and equitability of these trapped insects were calculated. The chemical screening of bait fermentation was done using Gas Chromatography and Mass Spectrometry (GC-MS). RESULTS: Significant difference (P < 0.05) in abundance of insect populations was found in treated compared to control trap. The insects of Noctuidae family recorded high Shannon- Wiener's diversity index followed by Muscidae. Margalef's index was recorded maximum in the treated traps (10.77) compared to those of control (8.09). The yielded index indicated that maximum richness was found in bait treated compared to control. The Shannon's equitability's values were investigated higher in Noctuidae (1.48), while, maximum evenness was observed in Muscidae (2.05) in treated trap. This fermentation was dried at room temperature and ground at 0.1 micron size. Our result showed significant (P < 0.05) effects of extraction times, with high yield in first extraction by polar solvents. Co-efficient of determination (R 2 = 0.87) recorded similar results in both extractions, however high root mean square error (0.97) recorded with bait + distilled water solvent showed linear arc line gave better performance. Finally, this fermentation was analyzed using GC-MS and recorded volatile compounds that were involved in the attraction of major and minor pests. CONCLUSION: Fermentation can help for the attraction of different families of insects of various crops. The field experiment suggested that this fermentation is economical, easily installed and consumed only 0.64 RMB/0.09 USD, including infrastructures per location. Bait fermentation is safe biochemical constituents and did not spread any toxic chemicals to the environment.

Insecticidal activity and biochemical composition of Citrullus colocynthis, Cannabis indica and Artemisia argyi extracts against cabbage aphid (Brevicoryne brassicae L.).

Plant extracts contain many active compounds, which are tremendously fruitful for plant defence against several insect pests. The prime objectives of the present study were to calculate the extraction yield and to evaluate the leaf extracts of Citrullus colocynthis (L.), Cannabis indica (L.) and Artemisia argyi (L.) against Brevicoryne brassicae and to conduct biochemical analysis by gas chromatography-mass spectrometry (GC-MS). The results suggested that when using ethanol, C. colocynthis produced a high dry yield (12.45%), followed by that of C. indica and A. argyi, which were 12.37% and 10.95%, respectively. The toxicity results showed that A. argyi was toxic to B. brassicae with an LC50 of 3.91 mg mL-1, followed by the toxicity of C. colocynthis and C. indica, exhibiting LC50 values of 6.26 and 10.04 mg mL-1, respectively, which were obtained via a residual assay; with a contact assay, the LC50 values of C. colocynthis, C. indica and A. argyi were 0.22 mg mL-1, 1.96 and 2.87 mg mL-1, respectively. The interaction of plant extracts, concentration and time revealed that the maximum mortality based on a concentration of 20 mg L-1 was 55.50%, the time-based mortality was 55% at 72 h of exposure, and the treatment-based mortality was 44.13% for A. argyi via the residual assay. On the other hand, the maximum concentration-based mortality was 74.44% at 20 mg mL-1, the time-based mortality was 66.38% after 72 h of exposure, and 57.30% treatment-based mortality was afforded by A. argyi via the contact assay. The biochemical analysis presented ten constituents in both the A. argyi and C. colocynthis extracts and twenty in that of C. indica, corresponding to 99.80%, 99.99% and 97% of the total extracts, respectively. Moreover, the detected caryophylleneonides (sesquiterpenes), α-bisabolol and dronabinol (Δ9-THC) from C. indica and erucylamide and octasiloxane hexamethyl from C. colocynthis exhibited insecticidal properties, which might be responsible for aphid mortality. However, A. argyi was evaluated for the first time against B. brassicae. It was concluded that all the plant extracts possessed significant insecticidal properties and could be introduced as botanical insecticides after field evaluations.