May 18, 2011 – If You Can’t Stand The Heat……
QUESTION:
I have questions about the degradation of pesticides in the heat. How does heat affect concentrates, such as being in the compartment of a truck bed? I have the same concerns about the final mixtures. Is it a problem if leftover mixed material heats up going from one job to another? I also am having problems with bait separation, such as Maxforce ant gel. It becomes a problem applying the bait after it has separated. Is the active ingredient being compromised? Does more stay in the gel part of the bait than the liquid that separates, or vice versa?
ANSWER:
These are some good questions, and two resources that are very important reading are the Product Label and the Product MSDS. I think we often overlook the importance of that MSDS, and just keep it on the vehicle or in the office to comply with regulations. But, the MSDS has vital Storage information on it specific to that product. I picked at random 3 products and looked at the label and msds for each one to see what guidelines or precautions they had specific to temperatures (we need to keep in mind COLD temps too).
Termidor SC - states on the Label only "protect from heat", but on the MSDS states that it should not be stored below 0 degrees Centigrade (= 32 degrees F) or above 40 degrees C (= 104 degrees F). It does not go on to say what the consequences would be if you did store it at that too high of a temperature, but the assumption is that it will affect the integrity of the product in some way - degradation of the active ingredient or a negative effect on the concentrate solution with respect to diluents and solvents in the product.
Dragnet SFR - states to store it above 40 degrees F, and further only states to store it in a "cool, dry location", without specifying higher temperature limits. Maxforce FC Ant Gel "recommends" a maximum storage area of 81 degrees F, and that the 30-day average temperature MUST not exceed that 81 degrees.
So this shows us that there may be no hard and fast rule for storage limits. Certainly the ideal storage will be room temperature, and temps that start getting above 100 degrees F can begin to cause problems for the material. We have been taught that heat is one of the enemies of pesticide molecules, hastening the breakdown of that molecule and reducing its life. Water is another enemy of the molecules, so leaving pesticides mixed in a tank in water is going to cause loss of the active ingredient. This may have been a greater concern with the old organophosphates, which were very susceptible to "hydrolysis", and less so with pyrethroids and newer chemical families, but good policy would be to never leave insecticide mixed up overnight, and certainly not over a weekend. Mix what is needed and use it on the job at hand.
The slight warming of the mixed material from one job to the next would not seem to be a serious concern. If you used cool or cold water initially it just should not warm to over 100 degrees in the next half hour. However, so much better to store that spray tank in an enclosed locker if at all possible.
With respect to the bait gels, you can see the warnings on the product documents, and this probably does have to do with thinning and separation of the gel. I suspect that the active ingredient is still just fine at these lower temps (below 100 F), but that the use of the gel to apply it properly would be hard if it is too runny. To be honest, I don't know if the liquidy part contains more of the a.i., but it would seem to me that the liquid part is exactly the same as that which is still a gel, but the gel part just has not melted yet. Over time if it stays liquid there could be some separation of the ingredients, but not right away. A good practice in the summer heat would be to store all materials like this in a small cooler in the storage compartment - perhaps a small styrofoam cooler and start with some ice in it.
View past Ask Mr. Pest Control questions.
I have questions about the degradation of pesticides in the heat. How does heat affect concentrates, such as being in the compartment of a truck bed? I have the same concerns about the final mixtures. Is it a problem if leftover mixed material heats up going from one job to another? I also am having problems with bait separation, such as Maxforce ant gel. It becomes a problem applying the bait after it has separated. Is the active ingredient being compromised? Does more stay in the gel part of the bait than the liquid that separates, or vice versa?
ANSWER:
These are some good questions, and two resources that are very important reading are the Product Label and the Product MSDS. I think we often overlook the importance of that MSDS, and just keep it on the vehicle or in the office to comply with regulations. But, the MSDS has vital Storage information on it specific to that product. I picked at random 3 products and looked at the label and msds for each one to see what guidelines or precautions they had specific to temperatures (we need to keep in mind COLD temps too).
Termidor SC - states on the Label only "protect from heat", but on the MSDS states that it should not be stored below 0 degrees Centigrade (= 32 degrees F) or above 40 degrees C (= 104 degrees F). It does not go on to say what the consequences would be if you did store it at that too high of a temperature, but the assumption is that it will affect the integrity of the product in some way - degradation of the active ingredient or a negative effect on the concentrate solution with respect to diluents and solvents in the product.
Dragnet SFR - states to store it above 40 degrees F, and further only states to store it in a "cool, dry location", without specifying higher temperature limits. Maxforce FC Ant Gel "recommends" a maximum storage area of 81 degrees F, and that the 30-day average temperature MUST not exceed that 81 degrees.
So this shows us that there may be no hard and fast rule for storage limits. Certainly the ideal storage will be room temperature, and temps that start getting above 100 degrees F can begin to cause problems for the material. We have been taught that heat is one of the enemies of pesticide molecules, hastening the breakdown of that molecule and reducing its life. Water is another enemy of the molecules, so leaving pesticides mixed in a tank in water is going to cause loss of the active ingredient. This may have been a greater concern with the old organophosphates, which were very susceptible to "hydrolysis", and less so with pyrethroids and newer chemical families, but good policy would be to never leave insecticide mixed up overnight, and certainly not over a weekend. Mix what is needed and use it on the job at hand.
The slight warming of the mixed material from one job to the next would not seem to be a serious concern. If you used cool or cold water initially it just should not warm to over 100 degrees in the next half hour. However, so much better to store that spray tank in an enclosed locker if at all possible.
With respect to the bait gels, you can see the warnings on the product documents, and this probably does have to do with thinning and separation of the gel. I suspect that the active ingredient is still just fine at these lower temps (below 100 F), but that the use of the gel to apply it properly would be hard if it is too runny. To be honest, I don't know if the liquidy part contains more of the a.i., but it would seem to me that the liquid part is exactly the same as that which is still a gel, but the gel part just has not melted yet. Over time if it stays liquid there could be some separation of the ingredients, but not right away. A good practice in the summer heat would be to store all materials like this in a small cooler in the storage compartment - perhaps a small styrofoam cooler and start with some ice in it.
View past Ask Mr. Pest Control questions.
