Pesticide Kill Redux

It has to do with the soil, rain and location.

By: Bob Brachmann

When the first break in the weather at the end of the 2007 – 2008 Winter gave me an opportunity to check my bees here in Southwestern New York, I was troubled.

Winter losses were higher than normal. As I reflected, I realized that it seemed that these losses looked to be a trend. In the preceding few years, I had made better than average Spring/Summer honey crops, but my Fall crops had been dropping and my percentage of Winter loss had been rising. While every year is different from every other year, my management had been consistent.

As I reflected, a disturbing possible explanation came to mind. 2005 was the first year that the local farms (all dairies) had planted corn whose seeds were ‘treated’ with systemic pesticides. Concerned with the possibility that these pesticides could be harming our honey bees, I approached both of the local farmers whose corn crops were in close proximity to our beeyards and asked if I could look at the seed bags before they planted their Spring crops. They cooperatively agreed and they both let me know when they had their seed. Both imidacloprid and clothianidin were listed as part of the seed treatments, as well as multiple fungicides. I then got online and read the ‘labels’ for these neonicotinoid insecticides. I’ll quote from the ‘label’ of one of those products, Poncho 600. Let it speak for itself.

Page 2; under “Science Findings”

…Clothianidin has the potential for toxic chronic exposure to honey bees, as well as other non-target pollinators, through the translocation of clothianidin residues in nectar and pollen.”

Page 15; under “Ecological Characteristics”

“Clothianidin is highly toxic to honey bees on an acute contact basis (LD 50 > 0.0439 mg/bee). It has the potential for toxic chronic exposure to honey bees, as well as other non-target pollinators, through the translocation of clothianidin residues in nectar and pollen. In honey bees, the effects of this toxic chronic exposure may include lethal and/or sub-lethal effects in the larvae and reproductive effects in the queen.”

Page 17; under “Mechanism of Pesticide Action”

“… The advantage of clothianidin and other neonicotinoids over nicotine is that they are less likely to break down in the environment.”

Page 18; under “Required Labeling for Treated Seed Bags”

“Treated seeds exposed on soil surface may be hazardous to wildlife. Cover or collect treated seeds spilled during loading.”

Forewarned with this information, telling me that these systemic pesticides MIGHT indeed be a problem for bees and our business, I decided to watch three select bee yards very closely. The first was our home yard (Y1). That year it was to be surrounded on all four sides by the corn grown from the seed I had investigated.    Second and third yards (Y2 and Y3) were in close proximity to fields of corn grown from the same seed.

(The corn pollen that I’ve observed has been a whitish-yellow color. The pollen ‘wheels’ brought into the colonies by the foragers are ‘looser’ than other pollen wheels I’ve seen, barely holding together; they disintegrate with the slightest handling. When one of these ‘wheels’ is pressed between one’s forefinger and thumb and ‘ground’ with a pressing, rotating motion, it feels a little granular but at the same time is VERY slick, similar to graphite. In my locale there’s an ‘early’ variety of goldenrod that provides a yellow pollen at roughly the same time as corn pollen is available. It is a deeper yellow color. If you are uncertain as to which pollen your bees are foraging, there are magnified images of individual pollen grains available and, with the aid of a good microscope, one can take samples from the field and verify the source of bee pollen.)

As corn began to tassel, I observed the pollen wheels coming into the colonies in those three yards regularly (not daily but nearly so). As ‘tasseling’ commenced, I noted an increase in the amount of corn pollen coming into the hives. There was a short-lived ‘surge’ in Yard 1 but this was quickly, and almost completely, displaced by knapweed pollen (a pale tan, creamy color). These bees traveled a mile away to a large field (60 acres?), which was full of it. Yard 2 brought in an initial surge of primarily corn pollen but then backed off on it and, for two to three weeks gathered a roughly equal mix of corn and knapweed pollen. Yard 3 brought in a surge of corn pollen, backed off it some, but continued to bring in predominately corn pollen for the longest time, a good three weeks.  I observed no unusual number of dead adult bees around any of these hives throughout this tasseling period and when the period of corn pollen availability ended (no more coming in) the near daily observations ended as well.

In the Southern Tier of New York State, beekeepers can often harvest a good crop of fall honey. All of my hives are well supered by mid-August in preparation for this flow. During the first week in September I make the rounds to add additional suppers as needed. The home yard, Y1, needed some additional supers. So did some hives in every other yard, except yards 2 and 3. Populations in yards 2 and 3 were down. The bees looked greasy; indicative of old or sick bees. By mid-October the colonies in Yard 2 were a sad bunch, some dead and none in any shape to make it through our zone 4 Winters. The Yard 3 colony condition was worse. All of Yard 3 was hauled into storage by November 1st, already a wipeout. I did prep a few colonies from Yard 2 for Winter but none survived that Winter. Though I don’t record these wintering numbers, Yard 1 wintered ‘normally’.

Now I had further concern; are the combs from the dead hives safe for use or are they contaminated and unusable. Inspection of these ‘dead outs’ showed that almost all of the corn pollen was gone, probably used up killing or damaging developing larvae. There was at that time an arrangement through Penn State University wherein a beekeeper could send samples of bees, pollen, honey or wax to a National Science Laboratory to have it screened for pesticide contamination under a cost shared arrangement. In December of 2008, I sent composite comb samples from likely pollen storage frames to be screened for 169 agricultural chemicals. Clothianidin and imidacloprid were not detected, or were below the LOD (limit of detection). (Four chemicals were detected at low levels, except perhaps for enaminone, a fungicide, at 138 parts per billion. But what constitutes a ‘low level’ ‘?’ I know that research has demonstrated that imidacloprid, listed alongside clothianidin as one of the active ingredients in the corn seed planted by my neighbors, affects larval development at 4 parts per billion.)

My response to these events was to find several new beeyards. I sought especially locations without corn but also places with knapweed nearby. It did not take long, however, for fields of corn to turn up near these new beeyards. In many cases these corn crops were planted in places that had not had field crops planted for decades. As my home yard was protected in 2008 by the presence of knapweed and the bees’ preference for that pollen over corn pollen, the new yards also exhibited no obvious severe symptoms – until 2016. Each year, if there was corn planted nearby, our honey bees would bring in a brief surge of corn pollen when the corn first ‘tasseled’ but would soon transfer most of their pollen gathering attention to knapweed.

In 2016 I planned so that the last queens we raised would all be mated by July 18th at the latest. As we try to make them up rather weak, and we end the last round of three-ways and four-ways by leaving one queen in each and combining the three or four mating nucs, providing for a strong ‘nuc mother’ heading into Winter, we often let this last round run as long as 35 days before we catch the last ‘extra’ queens and combine the three-ways and four-ways into a single colony.

On August 1st of last year we made the rounds of several bee yards to take an ‘overview,’ just observe what was happening in our colonies. The largest of our two mating yards was our first stop. I fired up a smoker and Carra and I pulled some frames from a three-way. My first thoughts to what I was seeing were “They’re still bringing in corn pollen. That means they’ve been bringing it in for weeks.” We drove to where, close by, there is plenty of knapweed. Very little bloom was showing.

What was different about 2016? It was a dry, hot summer here. I had noted in July that the corn had bolted in the dry hot Summer. Much of it was not as tall as it usually was when it tasseled but tassel it did, and earlier in the season than usual. The knapweed, on the other hand, had a greatly reduced bloom under these drought conditions. Honey bees know what they need in terms of nutrition and corn pollen is NOT a favorite, as it is missing most of the important amino acids that they need. Thus, they have a preference for knapweed. However, their foraging decisions are also influenced by the quantity available. The sparse knapweed bloom last year was just not enough to ellicit appreciable interest.

Another thing that was unusual about 2016 was a late July and early August honey flow. Other than making some honey on basswood about once every ten years, from mid-July to mid-August is usually a time of extreme dearth for the bees in my area. Our bees usually curtail or completely stop brood rearing in the second half of July and in early August.  Correspondingly, they also greatly curtail pollen gathering. But in late July of 2016 I noted the bees were bringing in a surplus, filling supers with a honey whose taste I was not familiar with. With frame of honey in hand, and a question in my thoughts, I turned to see an Aronia bush (Choke Berry) whose blossoms were thick with honey bees intently working the blossoms, and so it was in all of my yards. Aronia is common but is not listed as a honey bee nectar source in either Frank Pellet’s or Harvey Lovell’s extensive compendiums of same. For the last 24 years my beekeeping has been focused here in Western New York and I’ve never before seen honey bees fuss over Aronia. It was nice to get this honey but the bees probably would have been better off hungry. Instead of curtailing brood rearing our hard working bees shortened their lives nursing bees which, raised on royal jelly ‘produced’ from poison pollen, if they emerged at all, were useless to their colony.

Symptoms in The Hive

Personally, I’ve not seen symptoms in adult honey bees from the dust incidents associated with the planting of seed treated crops that have been reported by others. What I have seen is colony devastating symptoms in the brood. These symptoms don’t begin until almost three weeks after corn pollen is utilized to produce royal jelly (brood food). If you observe carefully you begin to see dead pupae being uncapped and removed from their hive. The colony still has an age balanced population; i.e., it has regulated itself to have what it deems an appropriate balance between young and old bees. There are plenty of young house cleaning bees.

Bees that develop on royal jelly derived from corn pollen sometimes fail to emerge. When there are plenty of young house cleaners present, these dead pupae (seem to be all purple eye stage pupae or older) are quickly uncapped and removed. Those that do emerge often appear indolent, or aimless. As time passes, colony population slowly diminishes. There is an absence of young bees. Dead pupae are often uncapped but not removed. Colonies seem to react by trying desperately to rebuild populations but are eventually unable to maintain the brood nest. At this point brood is dying because it’s not covered or fed. At the end there can be a tiny handful of bees, often tending to a queen. Last year some of my production colonies died this way by late August. Some of these dead colonies still had corn pollen stored in the bottom brood box. Other colonies used up the corn pollen and still had sufficient strength to continue to raise brood on other pollens. By September 12th I was seeing the first positive signs of recovery. And populations did eventually bounce back in many colonies, if not to normal, full size for Winter, they looked ‘passable.’

The challenge that they faced with Winter though was enormous. The bees in those Fall clusters were raised by old bees rather than young bees most suited to the task. Additionally, during this Fall recovery period is was ‘all hands on deck’ with brood rearing as they tried to rebuild their population. Bees that raise brood are not ‘Winter bees’. For purposes of longevity, they are old bees.  They did not have sufficient ‘Winter bees’.

Noted Differences in Regions/Soils

Problems from the translocation of neonicotinoids to brood from pollen seems to be high in the acid soil areas of the northeast while, at least to date, seems to be less of a problem in those areas with sweeter soil (higher pH). I suspect this is due to the presence of lots of legumes where the soil has a high pH. High pH soils favor the growth and natural reseeding of clovers and other legumes and these provide some of the most nutritionally rich pollens for honey bees.

Unfortunately, for those New York State beekeepers in the areas with sweeter soil, some of that ground is where the 2016 Summer drought was most severe. Aside from the drought’s negative impact on honey flows in those areas, it also affected the availability of pollen: those rich clover pollens, especially in the central state, may have been drastically reduced, possibly driving those bees also into collecting corn pollen. As I write this it is mid-March and losses reported in NYS are already extremely high. For me, it’s time once again to try to find new locations far from corn crops, a tall order in these parts but it appears as though I’ve little choice if I want to protect our honey bees, and our livelihood.

Bob Brachmann raises Russian Honey Bees in Little Valley, NY.