Comparative Bioefficacy of Different Citrus Peel Extracts as Grain Protectant Against Callosobruchus chinensis, Trogoderma granarium and Tribolium castaneum
2 Abstract: Efficacy of essential oils extracted from peel of various citrus species; Citrus reticulata, Citrus sinensis, Citrus paradisi and Citrus grandis were determined against the adults of Callosobruchus chinensis and Tribolium castaneum as well as against the larvae of Trogoderma granarium in order to find out safe alternatives of high toxics. Four concentrations of each oil; 2%, 4%, 6% and 8% were assayed for their insecticidal activity after exposure durations of 24, 48, 120 and 168 h. The results revealed that the essential oil vapors showed variable toxicity to insects depending on concentration and exposure duration. Efficacy increased as the exposure time and concentration were increased for all insects. All the oils were found to be very successful against adults of C. chinensis. Out of which, the oil of C. sinensis was the best against C. chinensis even at lower concentrations; LD , LD and LD values were 3.49%, 4.70% and 5.91% after 72-h 50 70 90
Effect of Acorus calamus (L.) (Araceae) essential oil vapours from various origins on Callosobruchus phaseoli (Gyllenhal) (Coleoptera: Bruchidae)
The toxic effects of vapours of essential oils of Acorus calamus (L.) rhizomes obtained from three countries on the adults and eggs of Callosobruchus phaseoli (Gyllenhal) reared on seeds of Lablab purpureus (Medik.) were studied. All oils were toxic to adults and eggs depending on exposure period and dose. Indian oil showed a strong latent effect, while an acute effect was more dominant in the Yugoslavian oil, followed by Russian oil. Significant reduction of oviposition was found in Yugoslavian and Russian oil vapours at 5 and 10 μl oil per 400 ml jar after 24 h exposure. Longer exposure periods increased the differences in egg production of treated and untreated insects. The fertility of the treated females was little affected. Newly-laid eggs were more susceptible than older ones, Indian oil vapours were the most effective.
Soil organic matter and microbiological development of technosols in the South Wales Coalfield
Abstract Degraded land (formerly ‘reclaimed’) after surface-coal-mining is a serious problem in South Wales. This project uses forestation to foster soil development on opencast coal-mine spoil technosols. It compares records of humification and the soil microbiological system (microcoenosis) using paired data from the same plantings in 1998 and 2018. Statistical analysis finds no significant difference between samples collected under trees planted by the pit-planting versus trench planting method or trees planted using organic or mineral fertilizer. However, there are strong significant differences in both soil organic matter and microflora components and significant correlations with time since tree planting. Most components of the soil organic carbon (TOC) and the microflora increase, often significantly. However, compared to 2018, 1998 samples contain significantly greater maximum levels of Insoluble Carbon while the microflora had significantly more Ammonifying bacteria. Decreases in Insoluble Carbon explain the relatively small increase in TOC between 1998 and 2018. The % extracted with 0.1 N H2SO4 is significantly larger in 2018, suggesting active weathering. Similarly, both the maxima and minima of total Humic and Fulvic acids content, extracted with 0.1 M Na4P2O7 + 0.1 M NaOH, are significantly greater in 2018. Total microflora shows significant positive correlations with time-since-tree-planting as do the proportions of bacilli and actinomycetes but the correlation with ammonifying bacteria is negative. In 1998, the microflora was dominated by non-spore-forming bacteria while, in 2018, bacilli and actinomycetes prevail; both are involved in the transformation of complex organic compounds and humification. This indicates active transformation of more complex organic compounds and advancing humification. In sum, forestation of these degraded, formerly reclaimed, opencast coal-mine spoils has resulted in a massive increase in both the size and functioning of the soil organic system.