Toxicity, Tunneling and Feeding Behavior of the Termite, Coptotermes vastator, in Sand Treated with Oil of the Physic Nut, Jatropha curcas

Oil of the physic nut, Jatropha curcas L. (Malpighiales: Euphorbiaceae), was evaluated in the laboratory for its barrier and repellent activity against the Philippine milk termite Coptotermes vastator Light (Isoptera: Rhinotermitidae). The study showed that J. curcas oil had anti-feeding effect, induced reduction in tunneling activity and increased mortality in C. vastator. Behavior of termites exposed to sand treated with J. curcas oil indicated that it is toxic or repellent to C. vastator. Toxicity and repellent thresholds, were higher than those reported for other naturally occurring compounds tested against the Formosan subterranean termite

The rph1 Gene Is a Common Contributor to the Evolution of Phosphine Resistance in Independent Field Isolates of Rhyzopertha Dominica

Phosphine is the only economically viable fumigant for routine control of insect pests of stored food products, but its continued use is now threatened by the world-wide emergence of high-level resistance in key pest species. Phosphine has a unique mode of action relative to well-characterised contact pesticides. Similarly, the selective pressures that lead to resistance against field sprays differ dramatically from those encountered during fumigation. The consequences of these differences have not been investigated adequately. We determine the genetic basis of phosphine resistance in Rhyzopertha dominica strains collected from New South Wales and South Australia and compare this with resistance in a previously characterised strain from Queensland. The resistance levels range from 225 and 100 times the baseline response of a sensitive reference strain. Moreover, molecular and phenotypic data indicate that high-level resistance was derived independently in each of the three widely separated geographical regions. Despite the independent origins, resistance was due to two interacting genes in each instance. Furthermore, complementation analysis reveals that all three strains contain an incompletely recessive resistance allele of the autosomal rph1 resistance gene. This is particularly noteworthy as a resistance allele at rph1 was previously proposed to be a necessary first step in the evolution of high-level resistance. Despite the capacity of phosphine to disrupt a wide range of enzymes and biological processes, it is remarkable that the initial step in the selection of resistance is so similar in isolated outbreaks

Efficacy of Major Plant Extracts/Molecules on Field Insect Pests

Insect pests are considered the major hurdle in enhancing the production and productivity of any farming system. The use of conventional synthetic pesticides has led to the emergence of pesticide-resistant insects, environmental pollution, and negative effects on natural enemies, which have caused an ecological imbalance of the predator-prey ratio and human health hazards; therefore, eco-friendly alternative strategies are required. The plant kingdom, a rich repertoire of secondary metabolites, can be tapped as an alternative for insect pest management strategies. A number of plants have been documented to have insecticidal properties against various orders of insects in vitro by acting as antifeedants, repellents, sterilant and oviposition deterrents, etc. However, only a few plant compounds are applicable at the field level or presently commercialised. Here, we have provided an overview of the broad-spectrum insecticidal activity of plant compounds from neem, Annona, Pongamia, and Jatropha. Additionally, the impact of medicinal plants, herbs, spices, and essential oils has been reviewed briefl

An In-Situ Thermogravimetric Study of Pyrolysis of Rice Hull with Alkali Catalyst of CaCO<inf>3</inf>

© Published under licence by IOP Publishing Ltd. Pyrolysis of rice hull (RH) with the presence of CaCO3 catalyst was carried out in this study to understand the effect of alkali catalyst in the thermal degradation behaviour and evaluate the kinetic parameter of rice hull for bio-oil or syngas production. Five different heating rates of the pyrolysis experiments at 10, 20, 30, 50, and 100 Kmin-1 were carried out in thermogravimetric analysis (TGA) equipment. Model fitting kinetic Coats Redfern integral method was applied in this study to estimate the activation energy (EA) and pre-exponential (A) value of catalytic pyrolysis in RH. The results showed that the maximum degradation increased from 6.69 to 52.67 wt% min-1 as heating rates increases from 10 to 100 Kmin-1. Besides that, the EA of the catalytic pyrolysis for RH using CaCO3 catalyst 60.86 kJmol-1 which is lower than other similar pyrolysis reaction reported in literature i.e. 77.4 kJ/mol. Meanwhile, the A value for the catalytic pyrolysis for RH using CaCO3 catalyst was 4.68×1010 min-1 which is significantly higher than 1.1×106 min-1 as reported in literature for non-catalytic pyrolysis of rice husk

Thermogravimetric kinetic analysis of in-situ catalytic pyrolysis of palm oil wastes with the presence of palm oil wastes ash catalyst

The thermal degradation and kinetic analysis for oil palm frond (OPF) and oil palm trunk (OPT) with its ashes were investigated using thermogravimetric approach (TGA). OPF ash, OPT ash and its mixtures are used as a natural source of catalysts in the pyrolytic conversion of the palm oil wastes to bioenergy. The TGA experiments were conducted in a range of heating rates of 10-100 K/min from the temperature of 323 K to 1173 K. Coats-Redfern model is applied in this study to evaluate the activation energy (EA) and pre-exponential factor (A). The average EA values ranged 24.27-32.36 kJ.mol−1 and 41.42-46.10 kJ.mol−1 for pyrolysis of OPF and OPT respectively. Meanwhile, the average EA values ranged 24.27-31.06 kJ.mol−1 and 31.77-43.45 kJ.mol−1 for catalytic pyrolysis of OPF and OPT respectively