I'd like to expand on Bob's comments. 

Through the Mn Apple Growers Association and University of Mn we have access to an apple scab hotline in spring. They sample old leaves from orchard floors and broadcast the spore count weekly in a phone message. Apple scab is probably the number one problem with apple growers in wet and humid climates like in the upper midwest and northeast regions. Its a fungus spread by spores which are activated by warm and wet weather in spring. If you get it under control during the early season post infections are not an issue. Scab control can make or break an apple crop in a wet year.

The hotline informs growers if we have enough spores present to create an infection if we have the right conditions of temp and moisture. This allows growers to hold off fungicide sprays until we are at threshold and even longer if there is no rain. 

A typical season would see scab season dormant during the pink stage of apple bloom and go above threshold during bloom in mid to late May here in MN. We can be above threshold but if it does not rain we have no infection. So growers who work with beekeepers in this region have an option of putting down a protectant like Captan on trees prior to bloom. Get the bees moved in and hope for no rain. If it rains within 7 days of a protectant spray we're ok. After the 7 day window any infection periods can be dealt with after rain by using a kickback fungicide like Nova or Sovram that work backwards up to 96 hours. Typically a grower will put down a protectant like Captan also at that time to save time and avoid a future after the fact spray.  This system has a lot of room to protect bees as if there is no rain you can skip some spraying for long periods during bloom.  Plus it minimizes sprays and the costs associated with them. 

As soon as petal fall occurs (bloom over), leaf roller, plum cucirlio and other secondary pests in this region are now able to attack the developing fruit. So growers are eager to move the bees out and put down an insecticide and maybe fungicide depending where we are in the scab cycle. Often the orchard still looks in bloom but experienced growers realize they most likely have a decent fruit set if good pollination weather and bees were present.  Also most orchards have early and late blooming varieties and the late bloomers are still getting pollinated. This first insecticide spray can be one of the most important as warm and humid weather during bloom gets many of the apple pests moving. 

This is when the pollinators get wacked in is this period by the petal fall sprays. Some of the systemic products offered by companies like Bayer are reccomended for application before actual bloom to presumably avoid this post bloom spray. I want to be clear that their systemic products are a vast improvement over the dangerous and toxic organophosphates that WILL be phased out someday soon. 

Here is a pretty good up to date guide of options for apple growers and the data compares how these new materials work as compared to the traditional organophosphates (OP). 

http://orchard.uvm.edu/uvmapple/pest/insects/AgnelloVT_OP_Alts_Feb2008.pdf

With all of that as a backdrop one can see how obvious it is that there are going to be possible fungicide/insecticide interactions at play in an apple orchard during or at the end of bloom when pollinaors are in the orchard.

My understanding of other row and orchard crops is this same kind of spray programs are routine and somewhat predictable.  

Anyone in the ag chem industry knows full well then that their products are unlikely to be applied as a single tank mix with out other additions. OR in the case of systemics on apple that were applied BEFORE bloom that the trace insecticides pollinators are exposed to in the pollen or nectar will also be present when large amounts of fungicides are being applied. 

While there is a late summer period of concern for apples here with a fungus called sooty blotch this is so far past bloom stage that an interaction is of no concern for pollinators. 

Therefore it should be of great concern to beekeepers that the chem industry and EPA focus on *bloom period * spray routines for crops that require pollinators. In other words given what we know about the potential for great harm in an insecticide/fungicide mix, any single testing of insecticides that will most assuredly be tank mixed with a fungicide during a crop bloom OR be present with fungicides via a systemic exposure must be tested for interactions or the testing is of little value to beekeepers in my view. 

While practices may differ between regions like Bobs area and mine, the overall issue of fungicide/insecticide interactions are real and need to be addressed and are common anywhere apples are grown. 

So yes I'm not sure Randy understood my post and its unclear to me if Bayer or other chemical mfgrs are going beyond the protocol in place by EPA that apparently does not require interaction testing. 

In my view once this interaction issue is addressed and organophosphates are delisted, we may be moving forward into a new era where we have a much safer environment for pollinators in orchards etc.  Grower/sprayer education will be critical to maximize the benefits of the new systemics. 

I do believe that the Bayer systemics are a move in the right direction and they appear to offer a way for a grower to achieve pest control by applying an insecticide before bloom that will then not expose a pollinator to that chemical directly in an application scenario. I hope readers realize that many of the systemics are problematic for bees during application like what occcurred in Germany with the clothidan corn coating. That situation can be minimized with proper knowledge and application timing and is often the source of misinformation on eco tree hugger types.  

I feel Bayer has done a good job of showing that the systemic traces that bees are exposed to are for the most part benign by themselves. Can the traces cause an interaction with a fungicide also? So I see two issues for interaction, the immediate spray mix or the potential for trace interaction with a fungicide that is sprayed later. 

Beekeepers may be wise to support Bayer then and encourage the more swift delisting of the old organophosphate materials that only work for 7-10 days and are surface sprays which leaves a known dangerous residue and offer little flexibility for application scenarios that protect bees. Unfortunately we will most likely have Farm Bureau and other Industry groups claim the sky is falling if organophosphates are delisted and just prolong the inevitable. 

This is a complex issue and unfortunately, some growers/applicators/beekeepers are not able to fully realize the benefits if they do not understand the issues of pre-systemic chemicals versus the new and emerging systemic era.  

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