Orchard Pollination - Honey Bees

European honey bees are the primary managed pollinators in orchards because their abundance can be managed from year to year.
Orchard Pollination - Honey Bees - Articles
Orchard Pollination - Honey Bees

Growers dependent on honey bees must constantly maintain a delicate balance between protecting their crops from pests and pathogens and protecting pollinators.

Due to competing demands, disease, the introduction of parasitic mites (mainly Varroa destructor), and likely impacts from insecticide and fungicide use in the field, however, the pollination picture has changed.

Despite intense efforts to protect their bees, beekeepers are losing large numbers of colonies to mites and the diseases they transmit. In addition, since 2006 there have been additional dramatic die-offs of tens of thousands of honey bee colonies from a phenomenon known as Colony Collapse Disorder (CCD). The result has been annual losses of around 30 percent of commercial colonies, which has left many beekeepers devastated and some growers without the quantity and quality of bees needed to pollinate crops.

CCD is under investigation and pesticide exposure is one of several contributing factors being studied. Pesticides under investigation include those used within the hive for mite and disease control as well as those used on crops that may inadvertently find their way into hives. Honey bees are vulnerable to many of the pesticides used to control insects, pathogens, and weed species. Growers dependent on honey bees must constantly maintain a delicate balance between protecting their crops from pests and pathogens and protecting pollinators. Until we have more documented information, it is advisable to err on the precautionary side when using pesticides.

Recommendations for growers

  • Know the pesticides you are using and their toxicity to bees (do not depend on a third party to provide this information).
  • Read the label and follow the label directions.
  • Never use a pesticide on a blooming crop or on blooming weeds if honey bees are present.
  • The use of a pesticide prebloom, just before bees are brought onto a crop, is not recommended. If a pesticide must be used prebloom (for example, at pink in apples), select a material that has a lower toxicity to bees and a short residual toxicity, and apply only when bees are not foraging, preferably just after dark.
  • Do not apply insecticides postbloom (e.g., petal fall) until after the bees have been removed from the crop.
  • Blooming time varies depending on cultivars. Bees pollinating one variety or crop may be at risk while another crop or variety is being treated postbloom with insecticides. Also, while crops may have completed blooming, bees may be visiting blooming weeds in and around crops. Be aware of these situations and avoid the application of pesticides on a nonblooming crop if there is risk of drift onto blooming crops and weeds if bees are present. If a spray must be applied, use the least toxic material and apply only when bees are not foraging.
  • Protect water sources from contamination by pesticides. If necessary, provide a clean source of water close to honey bee colony locations prior to their arrival in the orchard or crop.
  • The mode of action of many fungicides in terms of toxicity to bees is unknown. Some are known to synergize with insecticides, and together these can be more toxic to bees. Avoid the application of the more toxic fungicides mancozeb and captan on blooming crops when bees are present. The use of and lime sulfur during bloom has been shown to be repellent to bees for several days as well.
  • For more information on toxicity, see also other resources online such as a Northeastern IPM guide on preserving wild pollinators and several online publications at a pesticide stewardship webpage.
  • Do not assume that organically approved compounds are safe to bees.

As a result of mites, diseases, and CCD, fewer beekeepers are providing fewer honey bee colonies for growers and at much higher prices. In addition, the quality of honey bee colonies, at times, may be marginal for the purpose of pollination. Never before has the pollination situation been so critical. To ensure maximum crop yields, growers now must give careful attention and consideration to crop pollination.

Table 1-9. Toxicity of insecticides, miticides, fungicides, and blossom- and fruit-thinning agents to honey bees. The toxicity ratings also apply to native pollinators.
Honey bee toxicity ratingSystemic movement in plantsResidual toxicityExtended residual toxicity*Apply only during late evening, night, or early morning*Apply at any time
Insecticides/miticides
Acramite (bifenazate)

**

N

?

?

X
Actara (thiamethoxam)***Y
Has been found in nectar and pollen from prebloom spraysa
?
Found in pollen and nectar from pre-bloom sprays that may cause mortality to adults and larvae
7-14 daysX
Agri-Mek (abamectin/avermectin)***Y< 8 hours, can vary by formulationa and application rate1-3 days, can vary by formulations and application rateX
Altacor (renaxypyr)NTNX
Ambush/Pounce (permethrin)***N??X
Apollo (clofentezine)NTNX
Apta (tolfenpyrad)***N??X
Asana (esfenvalerate)***N?1 day; Toxic to bumble beesX
Assail (acetamiprid)*Y
Has been found in nectar and pollen from prebloom spraysa
?2 days for other beesX
Avaunt (indoxacarb)***N1 hour3 days for BBX
Baythroid (cyfluthrin)***N?>1 dayX
Belay (clothianidin)***Y?>5 days; More toxic to bumble beesX
Beleaf (flonicamid)*Y
Has been found in pollen from prebloom spraysa
1 hour
Short residual for leafcutter and bumble bees
?X
Belt (flubendiamide)NTNX
Brigade (bifenthrin)***N<0.04 lb ai/A
4-6 hours
>0.06 lb ai/A
>1 day
X
Bt-Dipel (Bacillus thuringiensis)NTNX
Calypso (thiacloprid)*Y
Has been found in nectar and pollen from prebloom spraysa
?1-2 daysX
Closer (sulfoxaflor)***Y
Has been found in pollen only from prebloom spraysa
X
Centaur (buprofezin)--chitin inhibitor IGR
(sublethal reproductive effects on adults w/in 24 hours of application, contaminated pollen lethal to larvae, ovacidal by contact, larval development disrupted in all types of bees)
NT
*** to larvae fed contaminated pollen and nectar
NX
Confirm (tebufenozide)NTX
Cydia pomonella granulosis virus(Carpovirusine, Cyd-X)NTNX
Danitol (fenpropathrin)***Y?1 dayX
Decis (deltamethrin)***N< 4 hoursX
Delegate (spinetoram)***Y3 hours?X
Diatomaceous earth (abrasive insecticide made from silicon remains of diatoms)**N<4 hours?X
Diazinon (diazinon)***N?2 daysX
Entrust (spinosad)***Y3 hours1 dayX
Envidor (spirodiclofen)--NT to adults, toxic to bee larvae if sprayed during bloom from contaminated pollen and nectarNT to adults
** larvae
N??X
Esteem (pyriproxyfen)--Juvenile Hormone IGR
(sublethal effects on exposed adults likely, ovicidal, and developmental effects on larvae)
NT to adults

***? to larvae and eggs
Y2 hours to reduce effects on adult bees?
Long residual with known developmental effects on the larvae and eggs of most insects
X
Ethrel (ethephon)NTX
Exeril (cyantraniliprole)***N??X
Grandevo (insecticide derived from bacterium, Chromoacterium subtsuge)**>1 day
Hero (zeta cypermethrin + bifenthrin)***NX
Horticultural mineral oils [<3 hours]**N3 hours?X
Imidan (phosmet)***N?3-5 daysX
Intrepid (methoxyfenozide)NTX
Kanemite (acequinocyl)NTNX
Lannate (methomyl)***Y2 hours36 hoursX
Leaverage (cyfluthrin + imidaclorprid)***Y
Has been found in nectar and pollen from prebloom spraysa
8 hours>1 dayX
Lorsban (chlorpyrifos)***N, but high vapor activity tends to fumigate area sprayedVaries w/ rate and formulation4-6 daysX
Malathion (malathion)***N<6 hours
May vary by formulation
2-5 days depending on rate and formulationX
Movento (spirotetramat)NT to adults
** to larvae from residues in pollen and nectar
Y?1 dayX
M-Pede (potassium salts of fatty acids/soap)NTNX
Mustang Max (zeta cypermethrin)***N>1 day
Nealta (cyflumetofen)NTNX
Neemix (insecticidal extract of Neem oil (ecdysone antagonist)**N<2 hoursX
Nexter (pyridaben)***N2 hoursUp to 24 hours with BB and LCX
Neemix (azadirachtin)**?< 2 hoursX
Orthene (acephate)--labeled for orchard border sprays for brownmarmorated stink bug***Y?
More toxic to bumble bees
>3 daysX
Portal (fenpyroximate)NTNX
Pounce (permethrin) possibly repellent***N?3-5 daysX
Proaxis (gamma cyhalothrin)***N1 day7 daysX
Proclaim (emamectin benzoate)***Y2 hours>1 dayX
Provado/Admire (imidacloprid)***Y
Has been found in nectar and pollen from prebloom spraysa
8 hours>1 dayX
Pyganic (pyrethrin)***N2 hoursCommonly formulated w/ synergist PBO, which extends residual to 1.5 daysX
Rimon (novaluron)--chitin inhibitor IGR (sublethal reproductive effects on adults w/in 24 hours of application, contaminated pollen lethal to larvae, ovacidal by contact, larval development disrupted in all types of bees)NT to adults
*** to larvae fed contaminated pollen and nectar
Y
Translaminar, local movement in plant tissue
?
Known to have long residual activity on many pests and beneficial insects
?
More research necessary on bees
X
Savey/Onager (hexythiazox)NTNX
Sevin (carbaryl)***N8 hoursFruit thinning rate
> 1 day
Insecticidal rate
3-7 days
X
Sivanto (Flupyradifurone)*Y
Has been found in nectar and pollen from prebloom spraysa
??X
Surround (kaolin clay)NT (repellent)NX
Vendex (fenbutatin-oxide)NTNX
Venom/Scorpion (dinotefuran)***YVery toxic to bumble bees39 hoursX
Voliam Flexi (thiamethoxam +chlorantraniliprole)***Y?
Found in pollen and nectar from prebloom sprays that may cause mortality to adults and larvae
7-14 daysX
Voliam Xpress (lambda cyhalothrin + chlorantraniliprole)***X
Vydate (oxamyl)***Y8 hours3-4 daysX
Warrior (lambda-cyhalothrin)***N1 day7 dayX
Zeal (etoxazole)NTNX
Fungicides/PGRs
Abound (azoxystrobin)
Flint/Gem (trifloxystrobin)

NT

N
X
Agri-Mycin (streptomycin sulfate)NTNX
Bravo (chlorothalonil)NT?
Common contaminant of beeswax
NX
Bayleton (triadimefon)*NX
Captan (captan)
(contaminated pollen may disrupt larval development in all kinds of bees)
**?NUp to 7 days for mason beesX
Dithane/Penncozeb/Manzate/Roper (mancozeb)NT to adults,
? toxic to bee larvae if sprayed during bloom from contaminated pollen and nectar
NX
Kocide (copper hydroxide)**NX
Lime sulfur/sulfurNT?
(possibly repellent)
NSome sources indicate toxicity up to 1.5 days, depending on rateX
NAA/1-Naphthaleneacetic acid (fruit thinner)NT (possibly repellent)YX
Polyram (metiram)NTNX
Pristine (pyraclostrobin + boscalid)*YX
Scala (pyrimethanil)NTNX
Strobilurin Fungicides (Flint, Sovran)NTNX
Serenade (Bacillus subtilis fungicide)NTNX
Sterol Inhibitor Fungicides (Rally, Nova, Procure, Indar, Inspire Super, Orius/Elite)NT
(possible synergism with insecticides)
Y
Has been found in nectar and pollen from prebloom spraysa
X
Sovran (kresoxim-methyl)*NX
Syllit (dodine)*Y
Has been found in nectar and pollen from prebloom spraysa
X
Topsin-M (thiophanate-methyl)NTNX
Vanguard (cyprodinil)/
Scala (pyrimethanil)
NTNX
Ziram (ziram)*NX

Source: Penn State Tree Fruit Production Guide