I thought about the herbicide also but since I spray my yards with roundup( also purposely sprayed it heavy on a pallet of 4 hives last year) and it had no apparent effect unlike the ares of no-till when dandelion in bloom( my yard with the worse sign had no round up applied). What I did notice was dead and dying bees wiggling in front of entrance. Did mite samples and with the very few mites found I would rule them out but not totally. All hives in yards that had problem( signs of pesticide kill) did not all have it at the same time(maybe they only work the"poison" until they sensed it was bad). It was noticed at the same time but was obvious some hives had kills from that day thay were still dying while the hive next door had nothing and the other hive next door had bees that were dead for a few days. Then it was good for a while and I noticed it again when there was bloom in close proximety to the corn(alfalfa and clover). But again it wasn't all hives affected.
You need to send a sample of bees to Beltsville. Then you will have a better idea of the place to start. Beltsville can rule out nosema ceranae which your problem sounds like at times. Beltsville will not detect most pesticide kills from my experience.
A Penn state sample to Maryann F. might turn up a pesticide problem and Penn State will do testing for around 40-50 bucks i have been told.
My experience is that those beekeepers which have been using fumidil on a regular basis usually have nosema ceranae issues which can be cleared up easily. Those which have never used fumidil or rarely and when they find their bees are testing 5 million spores per bee have spore counts on equipment so high that even when you get under control before long the bees are sick again.
In those cases equipment need acetic acid treatment to kill spores as spores can live up to 12 months and can not be seen (dysentary looking )with nosema ceranae like with nosema apis.
if my bees beeslave I would rule nosema ceranae out as step one after making sure varroa is under control.
While waiting I would drench with fumidil and feed syrup & pollen patties to the sick.
I had a lot of dead bees in front of my hives to right after planting corn and soybean two years in a row now. At same time there was dandelion was on edge of fields. I remember thinking, round up was not poisonous and wondered what had killed the bees since I use it around my hives too. I did not understand there was a potential of seed dust contaminating other flowers in the area till after some reading this last summer. I will have to keep my eyes open this next season.
I guess to get a contract with a grower for apple orchard pollination. He says that they will use fungicides spray at the night ones during the blooming. Will it be harmful for bees or not?
Depends. I would certainly find out what he's spraying. If it were me, I'd probably pass on the contract. I believe the bloom should be sacred and nothing sprayed while my bees are in the field.
"Corn Seed Treatment As Lethal As It Gets For Honey Bees All Season Long, And Long After The Season Is Gone."
the entire article is here
people need to realize that pollinating don't always mean big money. you need to charge more for the service, that way you might buy more bees.if if I did move my bees in a orchard there is contract no spraying and a up front price if bees die.
a post from bee-l on the corn/pesticide issue.
on the issue of reporting I'm not sure how you would know enough at the time it happened to know enough to report it.
> >Although the study has touched on my concerns quite a bit of research is
> still needed.
At the AHPA conference today, Bayer and EPA representatives reported.
The issue of contaminated dust from pneumatic planters was downplayed. I
brought it up during questioning, and found that they are not receiving
incident reports about it in the U.S., which surprised me. I asked to whom
reports by beekeepers experiencing seed dust problems such as in the paper
cited should be made.
Beekeepers experiencing bee kills due to planting dust should call Tom
Steeger at EPA directly, and Dick Rogers at Bayer directly.
Grass Valley, CA