# IGRs a problem in almond pollen?



## loggermike (Jul 23, 2000)

IGRs at Bloom: Bad Idea?
http://thealmonddoctor.com/almond/igrs-at-bloom-bad-idea/

And this:

8. Johnson, R. & E. Percel. The EFFECTS OF THE FUNGICIDE PRISTINE ON QUEEN REARING. The Ohio State University, Department of Entomology, Wooster, OH

There have been reports by commercial queen producers of occasional unexplained loss of large numbers of developing queens in the larval or pupal stage. Many of the affected queen-rearing operations are situated among the almond orchards of California and report these losses in the weeks after almond trees bloom. Almond flowers are a rich foraging resource for bees, but are also commonly treated with fungicides, insecticides and spray adjuvants during bloom to control pests and pathogens. Queen producers have associated queen developmental problems with application of the fungicide Pristine, which contains the active incredients boscalid and pyraclostrobin, and the spray adjuvants containing organosilicone compounds. To test the effect of these pesticides queens were reared in closed swarm boxes for four days, until capping, with nurse bees fed pollen treated with four concentrations of Pristine (0.4, 4, 40 and 400 ppm), an organosilicone-containing spray adjuvant (Break-Thru, 200 ppm), the combination of Pristine and Break-Thru (400: 200 ppm), diflubenzuron (100 ppm) as a positive control or water as negative control. Low concentrations of pyraclostrobin (50 ppb), but no boscalid, was detectable in royal jelly fed to queens in the 400 ppm Pristine treatment. No significant difference in queen survival to capping or adult queen emergence was observed between any of the experimental treatments and the negative control. Only diflubenzuron, the positive control, caused a substantial reduction in queen cell capping. Interestingly, diflubenzuron use in almonds during bloom, at roughly the same time and scale as Pristine application, has seen on a steady increase over the last decade. Future work should focus on the role of diflubenzuron, possibly in combination with other pesticides, on queen development, survival and success.
==========
Closing in on the problem?


----------



## beeman2009 (Aug 23, 2012)

I know I am dumb, but what are IGRs?

Thanks


----------



## Honey-4-All (Dec 19, 2008)

loggermike said:


> IGRs at Bloom: Bad Idea?
> http://thealmonddoctor.com/almond/igrs-at-bloom-bad-idea/
> 
> And this:
> ...



Eric Mussen gave a talk at the queen breeders meeting last Thursday in Ord Bend regarding this issue. Looks like the use of IGR's at fungicidal application time during bloom is a highly likely culprit in the demise of many queen cells a couple of weeks later. Putting two and two together with the beeks, pest advisors, and researchers at the meeting a high corellation regarding the beginning of the qc problems begging with the commencement of the use of the IGR's a few years back was established. Was thinking last night I ought to tell my growers that if they are going to use this stuff I need a 2 days heads up to bail out or they can fork over another 50 bucks for almond pollination. Use during bloom needs to be banned. Dead queen cells are not something I really want.....:no:


----------



## beebze (Sep 24, 2007)

insect growth regulators


----------



## beeman2009 (Aug 23, 2012)

beebze said:


> insect growth regulators


Thanks. Always seeking to be educated. :banana:


----------



## Honey-4-All (Dec 19, 2008)

beeman2009 said:


> Thanks. Always seeking to be educated. :banana:



If I understand the scenario correctly here's whats happening. 

To control peach twig borer the growers used to use dormant spray(oil) . Because of runoff issues in the Sacramento river the window of usage was diminished. Once that happened growers looked for alternatives for control. One option was to use IGR's.

Their use at the same time as fungicide application during the end of almond bloom allowed the foragers to carry the stuff home with the pollen. Once inside the hive it presence inhibits larval development by one of two modes depending on what class of chems being used. Bottom line is people were having issues with queen cells failing as a result.


----------



## jim lyon (Feb 19, 2006)

Queen cells are the "canary in the coal mine" in regards to hive health. I have seen an apparently healthy hive unable to raise healthy queen cells. In our case the problem is usually Yellow Jasmine pollen. The really frustrating thing is they may look fine up until about day 5 and then the bees will begin to chew them out. It is why I prefer to leave my cells in the builder until at least day 9. I feel the bees can do the best job of culling the undesirable cells if there is a problem. I have heard from other cell producers that they might have bouts with unhealthy cells and never find out the cause as it may go away as quickly as it came.


----------



## BernhardHeuvel (Mar 13, 2013)

loggermike said:


> containing organosilicone compounds


*An Inert Pesticide Adjuvant Synergizes Viral Pathogenicity and Mortality in Honey Bee Larvae*
Fine, J. D. et al. Sci. Rep. 7, 40499; doi: 10.1038/srep40499 (2017).
*http://www.nature.com/articles/srep40499#discussion*

Abstract

Honey bees are highly valued for their pollination services in agricultural settings, and recent declines in managed populations have caused concern. Colony losses following a major pollination event in the United States, almond pollination, have been characterized by brood mortality with specific symptoms, followed by eventual colony loss weeks later. In this study, we demonstrate that these symptoms can be produced by chronically exposing brood to both an organosilicone surfactant adjuvant (OSS) commonly used on many agricultural crops including wine grapes, tree nuts and tree fruits and exogenous viral pathogens by simulating a horizontal transmission event. Observed synergistic mortality occurred during the larval-pupal molt. Using q-PCR techniques to measure gene expression and viral levels in larvae taken prior to observed mortality at metamorphosis, we found that exposure to OSS and exogenous virus resulted in significantly heightened Black Queen Cell Virus (BQCV) titers and lower expression of a Toll 7-like-receptor associated with autophagic viral defense (Am18w). These results demonstrate that organosilicone spray adjuvants that are considered biologically inert potentiate viral pathogenicity in honey bee larvae, and guidelines for OSS use may be warranted.

Also see: https://en.wikipedia.org/wiki/Organosilicon


----------



## loggermike (Jul 23, 2000)

The study originally linked to seemed to clear the OSS and implicate Diflubenzuron (Dimilin) as the problem.I have been following the study that links OSS with BQCV with interest. My question is how much of the OSS actually would be found in the hives during almond pollination.

I suspect not enough to worry about.


----------

