As we learned from the paper by Isawa et al, DMI fungicides plus cyano-substituted neonics are very toxic to bees, more toxic than either one alone.



And as Jim pointed out, the degree of toxicity is still dwarfed by imidacloprid because the neonics acetamaprid and thiacloprid are so much less toxic to bees to begin with, that even after increasing their toxicity hundreds of times, IMI is still worse.  (IMI is the most widely used pesticide in the world, by the way).



But maybe there are cases where the combination of a DMI fungicide and one of those cyano-substituted neonics can be an unexpectedly toxic cocktail and kills bees.



So I spent some time trying to figure out if there are any correlations between the use of these compounds and complaints of bee kills from beekeepers, using Bee-L archives.  I realize there are probably much better national databases on bee kill incidents, so feel free to offer those and/or correct what I did.


Starting with the two types of pesticide:



Triflumazole (DMI fungicide) dramatically increases the toxicity of thiacloprid and acetamiprid (cyano substituted neonics) to honeybees.  However, by itself it has passed the EPA test as having low toxicity to bees.  It is marketed as “Procure” for outdoor use, and “Terraguard” for greenhouse use.  In recent years, increased permissions for outdoor uses have been sought.  Below are quotes from the manufacturers:



(1996) Procure 50WS is labeled to control powdery mildew and scab on apples, pears, and grapes. Procure SOWS (EPA Reg. No. 400-431) is a broad-spectrum foliar fungicide used to control diseases on apples, pears, and grapes.  Procure is applied by ground to grapes at a single rate of 0 25 lb. ai/acre and a  seasonal rate of 1 lb. ai/acre.  It is applied to apples and pears by ground or air at a single rate of 0.5 lb. ai/acre and a seasonal rate of  2 lb. ai/acre.  Procure 50WS contains 50h triflumizole.



As the mean field dissipation rate for triflumizole is eight days, chronic toxicity is not likely to occur.



(2002)  Procure 50WS (EPA Reg. No. 400-431) is currently labeled as a broad-spectrum foliar fungicide for

control of certain diseases of grapes and pome fruits (apples and pears) at a maximum application rate of one

 lb. ai/acre/season (grapes) and two lbs. ai/acre/season (pome fruits). The revised label adds use on cucurbits

 (1.25 lbs. ai/acre/season), cherries (3.0 lbs. ai/acre/season) and strawberries (1.0 lb. ai/acre/season).



The following statements come from the “Directions for Use” pamphlets:



Procure should be applied during full bloom on cherries.



Curcubits should be sprayed every 7 to 14 days until harvest.



Grapes should be sprayed before bloom and up to harvest every 7 to 14 days.



Calypso is the commercial Bayer product containing thiacloprid and it is used on the following crops:



Crop Group 11 Pome Fruit: Apple, Crabapple, Loquat, Mayhaw, Pear, Oriental Pear, Quince.

Directions:  For pear psylla, apply the higher rate when pest pressure is high. Target prebloom and postbloom to first cover when populations have reached economic thresholds and the majority of the population is in early instar stages. Reapply at 7-10 day intervals if monitoring indicates populations have reached economic threshold.

·

For European apple sawfly, apply the higher rate when pest pressure is high. Target petal fall when populations have reached economic thresholds. If there is a history of heavy sawfly pressure in the orchard, target the Calypso applications at pink and petal fall. Reapply at 7-10 day intervals if monitoring indicates populations have reached

economic thresholds.



Biscaya is a systemic insecticide (Thiacloprid) that provides you with control of pollen beetles in oilseed rape and mustard, aphids in broccoli/calabrese, brussels sprouts, cabbage, cauliflower, carrots, parsnips, peas, oilseed rape and potatoes and a reduction of damage by orange wheat blossom midge in wheat.



Acetamaprid (Assail):



For use on apples, aubergines, brassicas, cabbages, canola, cereals, citrus, cole crops, cotton, cucumbers, flowering plants, fruiting vegetables, grapes, leafy vegetables, lettuce, melons, noncrop uses, onions, ornamentals, palm fruit, peaches, peppers, pome fruits, potatoes, rice, stone fruits, strawberries, sugar beet, tea, tobacco, tomatoes, vines, water melon



Now to bee kill/sickened incidents:  Are beekeepers complaining about sick bees on/near these crops, and are any reporting the use of those pesticides?  From archives on Bee-L:



Peter Borst posted Beekeeper Says Chemical Affecting His Business



“Doan explains the chemicals aren't directly killing the bees, but they are making them forget how to be bees, which ultimately kills the hive.



Over the course of a summer, his farm usually supplies bees to 30 apple farms and 20 vine farms for products like squash. He says right now he can probably supply only about three farms. Farmers say these bees are important for them to stay in business.



"Without the bees the female flowers don't get pollen from the male flowers and therefore no squash, so bees are essential to our operation," said farmer Chris Martin.”



Jeremy Martin:



“I have a pretty serious pesticide issue to deal with.  Brood destroyed in around 200 hives.  I am wondering if any of these chemicals would be likely to leave lipophilic residue in the combs. Trade name "Tourismo", active ingredients flubendiamide and buprofezin.   Trade name

"Protocol", active ingredients thiophanate-methyl and propiconazole.”


(NOTE:  Propiconazole is another DMI fungicide)



Bob Harrison wrote in 2009 (Thread heading “Kansas Honey producers meeting”):



This is now outdated but was true in fall 2007.



Imidacloprid is sold under the brand names of Confidor, Merit, Admire, Legand, Pravodo, Encore, Gaucho, and premise and was registered in the mid 1990's for use on blueberries, citrus, cranberries, strawberries, pecans, stone fruits, cotton, corn, melons, vegetables, forestry, ornamentals, turf and others.



Thiamethoxam is sold under the brand names of Actara, Platinum, helix, cruiser, Adage, Meridian, centrie, and Flagship and was registered in December of 2000 for use on apple, pecan, stone fruits, melons, peppers, cotton, corn, and others.



Acetamiprid is sold under the brand names Assail, Intruder and adjust and was registered in March of 2002 for use on grapes, citrus, canola seed treatment, with other uses pending, pome fruits leafy vegetable, ornamentals and others.



Clothianidin, sold under the brand names Poncho, Titan, Clutch, Belay, and Arena was registered for use on canola & corn seed treatment. Registered June 2003.



Thiacloprid is sold under the brand name Calypso and was registered in September of 2003 for use on apples, pears, cotton & others.



Ghislain wrote in 2008 (thread was “Neonicotinoids”):



Bill Sharp wrote:

>I understand that early neonics were quite toxic to bees, but that much progress has been made in that regard (i.e. Assail and Calypso).



Do not know if this is true: thiacloprid (active substance of Calypso) has also been found in the honey from the colonies that crashed in the German catastrophe last spring.

See also: http://www.imkerdemo.de/



Paul Cherubini, 2008, Thread “Neonicotinoids”:



Bob Harrison wrote:



> Assail (acetamiprid) was responsible for some commercial bee kills as the label says you can spray while in bloom.(source David Hackenberg). Those growers responsible dropped the practice in order to get bees for pollination but the label still says OK to spray while in bloom.



Bob, the Assail labels in the USA state:

http://www.upi-usa.com/upi-crop-protection/Assail_insecticide.asp



"This product is toxic to bees exposed to direct treatment.  Do not apply this product while bees are actively visiting the treated area."



So although Assail may be applied during bloom, it cannot be applied when bees are actively foraging.



See also:

http://www.vegetablegrowersnews.com/pages/news.php?ns=1349



In the bee kill cases you mentioned, how do we know the grower/ applicator fully followed the label directions and sprayed the correct dosage and sprayed only when bees were not actively visiting the treated area?



Bob Harrison, 2008 “Neonicotinoids”:

I have real problems with what you say and have a hard time letting slip by unanswered. . Assail has been serious problems for beekeepers doing apple pollination. Your veiws (which may reflect your personal experience) may not include bee kills related to assail but assail was discussed at the commercial beekeepers meeting at the national convention and all greed posted problems. Bee kills were reported when growers sprayed during bloom while hives were in apples.



I have dealt with apple growers for decades and they all start timed spray programs starting with the first insecticide spray  as soon as the hives are pulled.  Many varieties grow on the tree from April to Sept./Oct. in Missouri. 7-8 months  2 sprays a month is 14-16 sprays and in certain years sprays for insects are needed more often.  The large orchards I deal with NEVER take a risk on a other than perfect crop.



Brian Ames, 2008, “Systemic Pesticides”:



(Northern States)  "Coddling moth is a June problem and bloom arrives in late April to mid May, so no we have no reason to use Assial here for Coddling Moth before bloom.  The growers I know through the MN Apple Growers Association do not spray insecticides before or during bloom as usually its too cool for them critters plus we have no fruit to get damaged yet. Growers putting down insecticides for insects before bloom are using a more scorched earth approach from my perspective."



----

There are probably many more such tidbits in Bee-L archives but I stopped with these.  The point I see here is that variability in geography (northern apples not treated the way southern apples are) farmers (some spray differently than others, may use different products) and seasonality (weather effects) can cause different outcomes regarding honeybee mortality.


I found almost no information on synergistic interactions within invertebrates among the different ag chemicals applied in given applications. The approval procedure for new pesticides is very careful and lots of good work is being done by the EPA, however little to no testing is required on synergistic interactions within non-mammalian species.  Once the chemicals are “on the market”, dosing by the users can be done any which way and there is very little oversight, as far as I can determine.   I know farmers rely on chemical industry advisors to help them decide what to apply, and I am sure they don’t spend money on things they don’t need (or think they need) yet there is no formal mechanism to ensure that incompatible formulations are not applied together.


Just like over-the-counter medications for people....you can buy them and despite label cautions, you can make yourself sick (or dead) by misusing them.  Am I wrong?



Christina


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