Glass is inert, can be cleaned with solvents and heat, so it can be reused. But plastic petri-dishes, vials, centrifuge tubes are omnipresent in laboratories, are disposable and can easily be modified. Of course one cannot use an aceton solution on polystyrene dishes or vials, but what are the disadvantages of coating plastic surfaces with insecticides for single use?
It is more likely that the pesticide will get bound in the plastic. Most likely adsorbed, but possibly chemically bound or diffused into the plastic. This may be good or bad.
Good: the dose that you apply is likely the dose experienced by the insect.
Bad: the dose that you apply in the field can be adsorbed, absorbed, or bound to the leaf surface. What you would like is a petri dish that mimics the physical/chemical properties of a real plant. Then you have a more realistic dose transfer model as the pesticide gets from the plant to the target insect.
Ugly: pesticides are seldom applied as a pesticide+diluent. Typically there are a range of adjuvants that are included in the formulation. These adjuvants will affect the physical and chemical interactions between the pesticide and the petri dish as well as the transfer of pesticide from the petri dish to the insect.
To make life simple, use glass because you don't know what you are getting with plastic.
You might argue that a plastic dish assay is more relevant because your application is to baseboards and floors for pest management in homes. This seems reasonable, so long as you are using the same plastics. The effect on HDPE will likely be different than the effect on polystyrene (or any other class of plastic).
If you can, match the application method to the expected application method in the field. The distribution of deposits on a surface (any surface) matters. What looks like a uniform coating to a person might have large gaps to an ant.
Dr Timothy A Ebert is right, the glass gives maximum exposure and minimal hindrance during bioassay that gives you better estimation of the pesticide effect and drive you to design better experiment strategy according to your object.
This paper may be of your interest: http://www.chowyang.com/uploads/2/4/3/5/24359966/206-1.pdf
plastic can react with your insecticide so it might change the toxicity of your insecticide consequently this will affect your results.
Perfectly explained by #Timothy A Ebert
Though, plastics have pushed their way into the formerly glass-dominated domain of the labware and now the need for glassware has been reduced with the introduction of unbreakable or single- use disposable plastic items , but the following qualities of Glass cannot be overlooked while evaluating and experimenting insecticide under bioassay.
1. Unlikely any other surface, Glass surface provide least hindrance and much transparency for clear observation while experimenting insecticide against testing insects, in bio-assay.
2. Surface of glass containers containing trace metals very often at high levels, reduces the chances of contamination of insecticide samples and chemical stress on to it.
3. Glass being completely oxygen impermeable, and leachables to the inorganic substances as compared to the plastics (i.e., O2 impermeable and leachables to the organic substance) supports the holding the toxicity of insecticide while experimentation or its storage.
4. Being hard towards the toxicity of insecticide, glass provide least opportunity for the stock solution of insecticide for reaction with its surface.
5. Being easy sterilizable, can be re-used after thorough washing.
5. Glass equipment are very much reliable in wall strength, temperature endurance, radiation stability, and chemical compatibility.
Moreover, due to the above mentioned potentials of Glass materials, these are preferred for handling insecticide in bioassay viz., bottle bioassay, paper-based bioassay, and biochemical and molecular methods while broader insecticide resistance monitoring strategy under Insecticide Vector Management Program, as prescribed by the World Health Organization (WHO) .
Therefore, answering #Rik Clymans, due to the above headed reasons, glass equipments (whether single use or multiple use following thorough washing and sterilization) should be preferred rather than the plastic coated surfaces with insecticides for single use.
Good Luck..!!!
RT
- Badges
- Science topic
- Similar topics
- Agricultural Science
- Agronomy
- Crop Science
- Crop