Systemic Pesticides = death :(
Been a while since I posted. I have been busy with all kinds of things. Most recently a talk on pollinators. During my research for this talk, I came across a really scary set of research papers and I have to share their info. They described the elimination of systemic pesticides through guttation drops. I will explain, but first a little background (please excuse the lengthiness of this post. I am trying to capture it in as few words as possible but it is hard for me as you know :).)
As most of you know, systemic pesticides are chemicals you typically apply to the soil, and or seed, that are taken up into the tissues of the plant. Insects are then (theoretically) exposed when they eat the plant. The most widely used of these chemicals are the neonicotinoids, specifically imidacloprid. Imidacloprid is the largest selling pesticide in the world. Chances are, if you purchase a plant at a commercial nursery, imidacloprid has been applied in the soil. Even if a salesperson tells you that they don't apply pesticides, they mean at the sales location (like a big box store). However, a systemic probably has been applied when the plant was first grown. Sometimes before it even germinates.
These pesticides have been implicated in colony collapse disorder (bees dying off). These pesticides are found in sub-lethal levels in nectar and pollen. The argument between scientists and the chemical companies is whether pesticides are responsible for CCD. It is difficult to prove conclusively because they are at sub-lethal levels.
I have seen at least one study that indicates that imidacloprid is found in flower nectars and that butterflies do not die drinking it. There is little research on what other effects it might have, other than death, because butterflies are not a commercially important species. Certainly, when applied to host plants, the caterpillars die.
However, this is the important scary part. I have now read two studies by researchers in Italy, that document high levels of systemic pesticides (including imidacloprid) in guttation drops. Guttation drops are water droplets expelled by plants at night. Plants use transpiration (the process of water moving through the plant through evaporation) to expel excess water and waste products. However, at night, they cannot use transpiration. So many have adapted by creating specialized cells to eliminate water and other waste products. What we think of as dew, is actually this process and the drops are called guttation drops. Many insects use this water, first thing in the morning to rehydrate.
Anyhow, the Italian researchers grew corn in fields, that the seeds had been treated with systemic pesticides. Bees where then exposed to the drops of water. They drank them and died within two minutes ( here is a video link but don't watch if you don't like seeing animals die https://www.youtube.com/watch?v=e8Nsn4KvjwM ).
These pesticides are commonly applied not only to your flowers but also to our yards. Advantage is a common turf pesticide used to kill grubs. It's main ingredient is imidacloprid. I will let you draw your own conclusions. However, I cannot walk through wet morning grass without thinking about this. the argument in use of systemics was that we were not exposed to them because they were in the soils. Whoops, looks like we could be exposed to them in higher levels than before.
Oh, and by the way, they are now saying that they last in the soil up to 500 days.
"...A Novel Way for Intoxication for Bees"