Resistance to the bacteria-derived insecticides spinosad (Conserve), abamectin (Vertimec), Bacillus thuringiensis var kurstaki (Btk) (Dipel), B thuringiensis var aizawai (Bta) (Xentari), B thuringiensis crystal endotoxins Cry1Ac and Cry1Ca, and to the synthetic insecticide fipronil was estimated in a freshly-collected field population (CH1 strain) of Plutella xylostella (L) from the Cameron Highlands, Malaysia. Laboratory bioassays at G1 indicated significant levels of resistance to spinosad, abamectin, Cry1Ac, Btk, Cry1Ca, fipronil and Bta when compared with a laboratory insecticide-susceptible population. Logit regression analysis of F1 reciprocal crosses indicated that resistance to spinosad in the CH1 population was inherited as a co-dominant trait. At the highest dose of spinosad tested, resistance was close to completely recessive, while at the lowest dose it was incompletely dominant. A direct test of monogenic inheritance based on a back-cross of F1 progeny with CH1 suggested that resistance to spinosad was controlled by a single locus.

Aim: This study aims to understand the distribution of Pomacea spp. in various rice fields of Peninsular Malaysia. Place and Duration of study: The study was conducted at twenty five rice fields from five states in Peninsular Malaysia (Selangor, Perak, Penang, Kedah and Kelantan) during the sowing and harvesting of off rice season-2013. Methodology: This study was carried out on rice fields of one acre in size which were further divided into four blocks. A 0.5m 2 quadrate was used for sampling and snails within the quadrate were collected, counted and identified based on their shell morphology by the experts. Results: Based on this study, Pomacea maculata was more abundant and widely distributed as compared to Pomacea canaliculata. Rice fields in Perak showed the highest population distribution of Pomacea spp. during both sowing and harvesting of rice.

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Children are the vulnerable group in the agricultural community due to their early exposure to pesticides through the dynamic interplay between genetic predisposition, environment, and host-related factors. This study aims to identify the possible association between the depression in blood cholinesterase level and genotoxic effect among farm children. The results of micronuclei assay and comet assay showed that the reduced blood cholinesterase level from organophosphate pesticide exposure is significantly associated with an increase in chromosome breakage and DNA strand breaks. These genotoxicity end points suggest that farm children's cells experience early DNA damage that may lead to uncontrolled cell proliferation during their adulthood. Thus, farm children who grow up near pesticide-treated farmland have a higher probability of developing cancer than children with minimal or zero exposure to pesticides.

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A nano-emulsion system was developed for pesticide formulation. Pseudoternary phase diagrams were constructed consisting emulsion system of long-chain fatty acid methyl esters (LFAMEs)/mixed surfactant/water and a quarternary component, glyphosate isopropylamine (IPA) as a herbicide active. Isotropic (L) regions were formed in the phase diagrams using mixed surfactant long-chain alkylpolyglucosides (LAPG) and ethoxylated -(3hydroxypropyl)-heptamethyltrisiloxane (organosilicone) at the ratios of 9:1, 8:2 and 7:3. Preformulation concentrates were chosen from the L regions with less than 20% (w/w) of inerts (LFAMEs + mixed surfactant) and were characterized with regard to particle size, particle aging rate and thermostability study. A pre-formulation concentrate with the lowest aging rate and stable at high temperature (54 °C) was selected for the mechanisms study of the preformulation concentrate in conjunction with the development of nano-emulsion formulation. The transmission electron microscopy (TEM) result showed that the pre-formulation concentrate appeared as a polymerized multi-connected network. Upon water dilution of the pre-formulation concentrate with gentle stirring (low-energy emulsification method), welldispersed nanoparticles were formed with no needle structure being observed. The nanoemulsion particles were incorporated well with the glyphosate IPA thus inferring that this nano-emulsion system could ameliorate the bioactivity and bioavailability of the herbicide.

Herbicidal potential of aerial parts of Tinospora tuberculata on germination and seedling growth of seven test plant species, namely rice (Oryza sativa L.); two rice weeds, barnyardgrass (Echinochloa crus-galli L.) and weedy rice (O. sativa f. spontanea); and four vegetable crops, lettuce (Lactuca sativa L.), tomato (Solanum lycopersicum L.), carrot (Daucus carota L.), and cucumber (Cucumis sativus L.) were evaluated. Six concentrations of methanol extract (3.12, 6.25, 12.5, 25, 50, and 100 g L −1 ) were compared with the control (distilled water). The rate of seed germination and the radicle and hypocotyl length of 7-day-old test plant seedlings were reduced as the concentration of extracts increased compared to the control. Generally, the degree of toxicity of extracts derived from the leaves was more than the extracts derived from the stem. Cluster analysis and the concentrations required for 50% inhibition (defined as EC 50 ) of all parameters showed that radicle growth was more suppressed than germination and hypocotyl growth. Lettuce and carrot were observed as the most sensitive plants while rice showed the highest tolerance to both extracts. Moreover, the dicot target plants were affected more severely than the monocots when treated with leaf extract. The chemical composition of the T. tuberculata methanolic extracts was analyzed by a GC-MS system. A total of 92 and 22 constituents (not previously identified) were found in the leaves and stem, respectively. The results showed that 17 of the 92 components in the leaves, as compared to 4 of 22 compounds in the stem, are known as toxic compounds. These results suggest that T. tuberculata contains a significant source of plant growth inhibitors with potential for the development of future natural herbicide.

This study aimed to improve the efficacy of azadirachtin (Azadirachta indica. A. Juss) against two serious pest species of stored products, Sitophilus oryzae (L.) and Tribolium castaneum (Herbst), through nano-emulsion formulations. Pseudoternary phase diagrams were constructed consisting of an emulsion system of an active ingredient (neem oil), surfactant (polysorbate or alkylpolyglucoside), and water. Isotropic regions were formed in the pseudoternary phase diagrams, and four formulations were selected from the isotropic regions and characterized according to particle size, particle aging, zeta potential, stability and thermostability, surface tension, viscosity, and pH. The selected formulations showed particle sizes of 208-507 nm in diameter.The result of contact toxicity demonstrated excellent mortality of S. oryzae and T. castaneum adults, with a mortality range of 85-100% and 74-100%, respectively, at a 1% azadirachtin concentration after only 2 days of exposure. Compared to non-formulated neem oil, the nano-emulsion formulations significantly increased the mortality of the tested species.