Effect of adding mineral oil to the effectiveness of Permethrin Emulsion spray droplets on plutella xylostella larvae

The effectiveness of permethrin emulsion spray droplets with (10% v/v) and without mineral oil was evaluated in the laboratory by bioassay using larvae ofPlutella xylostella. A microtip nozzle was used to produce spray droplets ranging from 52 - 274 ~m in volume median diameter. The 2nd instar larvae were placed on treated leaf discs, and knockdown and mortality were recorded after 1 hand 24 h respectively. In both treatments, as droplet size decreased the dose also decreased without losing the effectiveness ofpermethrin indicating that small droplets were more ejjicient than large droplets. VVhen sprayed using droplet size between 70 ~m to 100 ~m, there was no increase in the effectiveness ofpermethrin from emulsion spray droplets plus mineral oil compared to emulsion spray droplets alone. However, for droplet sizes greater than 125 ~m, the effectiveness was reduced

Effect of thiobencarb formulations on freshwater shrimp, macrobrachium lanchesteri (De Man)

The effect of com-cob controlled-release formulations (CRF) of thiobencarb ( TAl and T A2) and alginate CRF (TAL 70192) to the freshwater shrimp, Macrobrachium lanchesteri (De Man), in comparison to a conventional granular formulation was studied in the laboratory. Mortality ofthe shrimps 24 h after exposure to the conventional formulation was significantly higher (P <= 0.05), and increased to 93.3% after 120 h. The CRF of TAl, TA2 and TAL 70192 caused mortality of 19.2,5.8 and 8.5%, respectively, 120 h after exposure. This difference is due to the slower release of thiobencarb using CRF

Ketoksikan Beberapa Racun Hamama dan Piretroid Timan terhadap Hamama Lelabah Merah, Tetranychus urticae Koch Kompleks

The toxicity of four acaricides and five synthetic pyrethroids against red spider mite, Tetranychus urticae Koch complex, was evaluated in the laboratory using the slide-dip technique. Mortality was recorded at 48 h post treatment and data were subjected to probit analysis. Based on the LC50 values, the order of toxicity of the chemicals tested was as follows: amitraz > deltamethrin = cypermethrin (CymbushR ) = fenvalerate > cypermethrin (RipcordR) > permethrin > bromopropylate = chinomethionate > azocyclotin. The LC50 value for amitraz was 2.5 ppm while for chinomethionate it was 37.5 ppm. Repeated tests on the toxicity of the pyrethroids using leaf dip technique at the LC50 and LC95 values obtained earlier from the slide-dip technique revealed a lower level of mortality. The highest mortality obtained was 21.0% from fenvalerate treatment at the LC95 value. Thus test techniques were found to give different toxicity values on the red spider mite

The future of pesticides technology in agriculture: maximum target kill with minimum collateral damage

Pesticides are widely used in agricultural production and have on human existence. They have been credited with increasing crop yields, protecting land and property, and even saving human lives. At the same time, pesticides are associated with some of the problems in agricultural production particularly those pertaining to pollution of the environment. The new paradigm in socio-environmental consciousness imposes on agricultural production to not only generate income but to be socially-responsible, sustainable and have minimum impact on the environment. In principle, sustainable agriculture espouses minimum use of pesticides, and only a last resort. However in practice, this seldom happens and pesticide usage is deemed a necessary evil especially in areas of heavy pest infestation. There is therefore a cogent need to reconcile the necessity of pesticide application with the damage visited on the ecosystem. Towards this end, this lecture will present the options of effective pesticide application with respect to choice, formulation and delivery technology for maximum impact with minimum collateral damage. Optimal dosage delivery that maximizes the biological effect on the target through the concept of controlled-release is one of the options to minimize the environmental impact of pesticides. Controlled-release of pesticides utilizes a depot system that continuously releases the active ingredient into the environment over a specified period of time. This would reduce the frequency of pesticide applications. Another novel approach to pest control is the use of biological pesticides or biopesticides. These are biorational (biologically rational) or ecorational substances that, when used for specific pests, have very limited or no effect on non-target organisms or the environment. The US Environmental Protection Agency defines them as any substances of natural origin that have a detrimental effect on specific target pests, possess a unique mode of action, and are non-toxic to man and the environment. They can either be living microbes and invertebrates, biochemical derived from living organisms The Future of Pesticides Technology in Agriculture or plant-incorporated protectants (eg transgenic Bt corn). The botanical insecticide, rotenone, extracted from the root of the tuba plant, Derris ellipfica has been shown to perform similarly to the standard synthetic compound. Similarly, entomopathogenic fungi from the Hyphomycetes, which are naturally responsible for epizootics (disease epidemics) in insect pest populations, Have good myco-insecticidal properties. Formulating the natural compound of entomopathogenic fung efficacy and ease of application in the field, minimizing handling hazards and accommodating the operational practices of Malaysian represents monumental allenges. The microemulsion of rotenone and water sible mefarhizium spores have been successfully formulated. A major problem in the application of pesticides is that a large proportion of the pesticide does not reach the target, with spray efficiency, particularly with insecticides, estimated to be less than 1%. Research in finding a solution that would have far reaching commercial and environmental implications has been directed to the spray volume application rate, selection of an appropriate atomizer and equipment calibration. The final product would be a precision equipment, calibrated to deliver the recommended dosage Of pesticide with an optimum spray droplet size and exact number dropletsper given area. This technology would vastly improve the efficiency of utilization of the active ingredients of the pesticide. The above development and research findings pave the way for the future not only in ensuring the most effective application of pesticides for crop protection, but also in enhancing food safety and protecting the ecosystem

Biotype and insecticide resistance status of Bemisia tabaci populations from Peninsular Malaysia

Bemisia tabaci, a resistance-prone insect pest, is a cryptic species complex with important invasive biotypes such as B and Q. The biotype and resistance statuses of this pest in Malaysia remain unclear. This study assessed the biotype and resistance status of a number of contemporary populations of B. tabaci based on the mtCO1 marker and the dose-response method, respectively. The Pahang (PHG) population was labelled as the Q biotype, while the remainder of the populations belonged to the Asia 1 biotype. A very low level of resistance for profenofos, cypermethrin, and imidacloprid was detected for all populations [resistance factor (RF) 100). All populations showed a very low level of resistance against pymetrozine except Q-type PHG population, which exhibited a very high level of resistance. For most insecticides, the highest level of resistance was detected in the PHG population. The implications of these findings for better management of this noxious pest are discussed