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
Bioefficacy of single and mixed applications of Citrus paradisi Maef and Citrus aurantifolia Swingle peel extracts against seed beetle, Callosobruchus maculatus (F.) (Coleoptera:Chrysomelidae).
The present study was conducted to determine the effects of grapefruit, Citrus paradisi Maef and lime, Citrus aurantifolia Swingle peel extracts on the storability of cowpea seeds. Cowpea samples were treated with various concentrations of single application (0.6, 0.8 and 1.0%) of extracts and their mixtures in the ratios of 1:1; 1:2; 2:1; 1:3; 3:1; 3:2 and 2:3 was applied at 5% level of concentration. Increasing extract concentrations resulted in better cowpea protection as recorded in oviposition where the control had mean number of 4.33 eggs, while oviposition was inhibited in 0.6 and 0.8% lime-treated sample at 7 days after treatment (DAT). Generally, better results were obtained with higher extract concentrations in single application. The bioassay revealed that grapefruit : lime mixture (1:2) gave 27.8% adult mortality at 24 hours post treatment (HPT) which increased to 50% 72 HPT. However, peel extracts applied in the ratios of 2:1 and 1:1 also gave 50% adult mortality during the same period. Adult emergence of Callosobruchus maculatus in the seeds showed significant differences while the percentage emergence of beetle was highest in seeds treated grapefruit : lime applied at 3:2 (12.67%), lowest percentage emergence of beetle was obtained in extracts mixture at 2:1 (0.33%). The mean fecundity in the mixtures showed that C. maculatus was most fecund (27.00 eggs) in the ratio (3:2) and least fecund in the ratio of 2:1(0.67 eggs). Maximum deterrent activity in oviposition, adult emergence and seed damage was observed at 2:1 (grapefruit : lime) peel extracts in all the treatment mixtures. Based on this study, grapefruit : lime ratio (2:1) peel extracts could be suggested for the use to suppress populations of C. maculatus for short period of storage.
Chemical, biological, and immunological characterization of mono- and diiodothyrotropin releasing factor.
Abstract Iodination of thyrotropin releasing factor (TRF) with chloramine-T and NaI at pH 7.5 produces both mono- and diiodo-TRF as well as unreacted TRF and I − . The four compounds can be separated by ion-exchange chromatography on SP-Sephadex C-25, using a stepwise gradient of 0.01 m MH 4 OAc at pH 3.5, 5.2 and 7.2. The monoiodo-TRF was characterized by nuclear magnetic resonance, mass spectra, and elemental analysis as [Im-5-iodo-His 2 ]-TRF while the diiodo-TRF was similarly characterized as [Im-2,5-diiodo-His 2 ]-TRF. Both iodination products showed no thyrotropin releasing activity at doses up to 1 μg in the in vivo mouse bioassay. The specific binding of mono- and diiodo-TRF was measured against three different TRF antisera. In the absence of TRF, antisera A and C bound more diiodo-TRF than monoiodo-TRF while antiserum B seemed to bind both tracers equally. In all cases steeper curves were produced when diiodo-TRF was displaced by synthetic TRF.