Honeybees and native pollinators visit fruit crops during flowering and pollen shed. In crops such as blueberries, their activity is crucial to the success of the crop. In other crops such as grapes, bees are among many beneficial insects who seek out pollen or nectar resources as a food source, but crop yield does not depend upon their activity. Strawberries and brambles benefit from the presence of pollinators but are also achieve some level of pollination from wind blown pollen. Populations of honeybees and native pollinators have declined worldwide in recent years. A wide range of factors have contributed to their decline; pesticides applied to crops is one of these.
Pesticides applied to protect fruit crops can affect pollinators through multiple routes of exposure: direct contact with sprays, contact with treated surfaces, pesticide-contaminated dust or pollen particles that are collected or adhere to the body of the insect (and may be taken back to hive), and ingestion of pesticide-contaminated nectar. Decisions made by the farmer make a difference in the exposure of bees and other beneficials to lethal or sublethal levels of pesticides. While pesticides applied to crops are only one among many factors that threaten pollinators, this is one factor that growers can do something about. Taking precautions to minimize pesticide poisoning of pollinators in all crops is an important responsibility of all pesticide applicators.
Reducing pesticide injury to honey bees requires communication and cooperation between beekeepers, farmers and applicators. It is important that beekeepers understand cropping practices and pest management practices used by farmers in the vicinity of their apiaries. Likewise, insecticide applicators should be sensitive to locations of apiaries, obtain a basic understanding of honey bee behavior, and learn which materials and application practices are the most hazardous to bees. While it is unlikely that all poisonings can be avoided, a balance must be struck between the effective use of insecticides, the preservation of pollinators and the rights of all--the beekeeper, farmer and applicator. In most cases, bee poisonings can be avoided by observing the following practices.
Timing. Avoid applications when crop or weeds are in bloom. In crops that bloom over long periods, make applications late in the day or at night when pollinators are not foraging, and so that there is sufficient drying time before foraging begins. Control weeds within the planting but allow for some blooming native plants in field edges and hedgerows as forage habitat when crops are not in bloom. Take care to avoid spray drift in areas where pollinators are foraging when spraying.
Formulation. Wettable powders, dusts and microencapsulated products have a greater toxic hazard than emulsifiable concentrates (or other liquid formulation with active ingredient in solution). Products that do not have acute toxicity but could cause injury to immature bees if carried back to the hive should not be applied in particulate form; this includes insect growth regulators.
Drying time before exposure. Some products are highly toxic when wet, but much less so after the pesticide is dried. Spinosyns have this characteristic. Apply when there will be adequate drying time (usually 2-3 hours, depending on weather conditions and crop canopy) before pollinator activity. Applying these materials in the evening can help achieve good drying before pollinators become active again the following day. If temperatures following treatment are unusually low, insecticide residues can remain toxic longer than if higher temperatures prevail.
Drift. Avoid drift on non-target areas near the field where blooming plants may be located. Windspeed and application equipment both influence drift. In general, sprays should not be applied if wind speed exceeds 10 mph.
Mode of application. Soil applications reduce exposure compared to foliar applications, unless plant uptake of the active ingredient produces residues in pollen or nectar. In the case of neonicotinoids, there is evidence that foraging bees may receive sublethal doses in pollen and nectar when crops were treated with a systemic at early growth stages. This effect appears to be reduced by using lower rates and applying as early as possible, but may not be entirely eliminated by these methods. A sublethal dose may make bees more vulnerable to other stressors, or may combine with doses from contact with other treated plant material.
Acute toxicity. EPA registration includes an acute, single-dose laboratory study designed to determine the quantity of pesticide that will cause 50% mortality (LD50) in a test population of bees.
Read the label for bee hazard rating. If a pesticide is used outdoors as a foliar application, and is toxic to pollinating insects, a “Bee Hazard” warning and easily identified Bee icon is required on the label. In addition a standardized information box is also required.
The EPA bee toxicity groupings and label statements are as follows:
High (H) Bee acute toxicity rating: LD50 = 2 micrograms/bee or less. The label has the following statement: "This product is highly toxic to bees and other pollinating insects exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product or allow it to drift to blooming crops or weeds if bees or other pollinating insects are visiting the treatment area." If the residues phrase is not present, this indicates that the pesticide does not show extended residual toxicity.
Moderate (M) Product contains any active ingredient(s) with acute LD50 of greater than 2 micrograms/bee, but less than 11 micrograms/bee. Statement: "This product is moderately toxic to bees and other pollinating insects exposed to direct treatment or residues on blooming crops or weeds. Do not apply this product if bees or other pollinating insects are visiting the treatment area."
Low (L) All others. No bee or pollinating insect caution required.
For an easy to use, sortable list of materials, their EPA bee toxicity ratings and synergistic effects with other materials see: https://www2.ipm.ucanr.edu/beeprecaution/
See below, Tables 12a and 12b, for information about the hazards posed to non-target organisms by several common small fruit pesticides.
| Active Ingredient (common product names)** |
DURATION OF HAZARD TO HONEYBEES (Residual Toxicity) | Active Ingredient (common product names)** |
DURATION OF HAZARD TO HONEYBEES (Residual Toxicity) |
|---|---|---|---|
| EXTREMELY to Highly TOXIC: DO NOT APPLY ON BLOOMING CROPS OR WEEDS | |||
| *Beta-cyfluthrin (*Baythroid, *Leverage, *Tempo) |
1 day RT§ |
Lambda-cyhalothrin (Warrior, Voliam) |
> day ERT > day ERT for encapsulated formulation |
| *Bifenthrin (*Brigade, *Sniper) |
< 1 day RT > 1 day ERT |
Malathion (Malathion, Cythion) |
2-6 hrs RT 2-5 days ERT |
| Carbaryl (Sevin) |
< 1 day RT 2-14 day ERT |
*Methomyl (*Lannate, *Nudrin) |
2 hrs RT 1.5 days ERT |
| *Chlorpyrifos (*Dursban, *Lorsban) |
2 hrs RT 4-6 days ERT |
*Naled (*Dibrom) |
2 hrs RT 1-1.5 days ERT |
| Clothianidin (Belay, Clutch) |
? RT > 5 days ERT |
Phosmet (Imidan) |
3-5 days ERT |
| Copper Sulfate + Lime (Bordeaux Mixture) |
? | Pyrethrin (Azera, Pyganic, Pyrenone) |
< 2 hrs RT |
| *Cyfluthrin (*Baythroid, *Tombstone, *Tempo) |
? RT > 1 day ERT |
Pyridaben (Nexter, Pyramite, Sanmite) |
< 2 hours RT > 8 hrs ERT |
| *Diazinon (*Diazinon) |
? RT 2 days ERT |
Sabadilla (Veratran-D) |
1 day ERT |
| Dinotefuran (Venom, Scorpion) |
? RT 39 hrs ERT |
Sulfoxaflor (Closer) |
3 hrs RT |
| *Esfenvalerate (*Asana) |
< 1 day RT 1 day ERT |
Thiamethoxam (Actara, Platinum, Voliam) |
7-14 days ERT |
| *Fenpropathrin (*Danitol) |
< 1 day RT 1 day ERT |
*Zeta-cypermethrin (*Mustang, *Hero, *Mustang Max) |
> 1 day ERT |
| Imidacloprid (Admire, Brigadier, Merit, Pasada, Provado) |
8 hrs RT > 1 day ERT |
|
|
|
Indoxacarb |
|||
| MODERATELY TOXICA: APPLY ONLY DURING LATE EVENING, NIGHT, OR EARLY MORNING IF BLOOMING PLANTS ARE PRESENT. | |||
| Acetamiprid (Assail) |
2 day ERT | Copper Hydroxide ( Badge, Champ, Kocide, Nu-Cop) |
? |
| Azadirachtin (Neemix, Aza-Direct, Azera) |
2 hr RT | Horticultural Oil (Superior, Dormant, Summer) |
< 3 hr RT |
| Beauvaria bassiana (Mycotrol, Botaniguard) |
? | Novaluron (Rimon) |
? |
| Bifenzate (Acramite) |
? | Oxydemetonmethyl (Metasystox-R) |
< 2 hours RT |
| Capsacin (Hot pepper wax) |
? | Petroleum/Paraffinic Oil ( JMS Stylet Oil) |
< 3 hours RT |
| Chlorfenapyr (Phantom, Pylon) |
< 4 hr RT > 2 day ERT |
Spinetoram (Delegate, Radiant) |
3 hour RT |
| Spinosad ( Entrust, Success) |
? | ||
| Chromobacterium subtsugae (Grandevo) |
? | Spirotetramat (Movento) |
? |
| SLIGHTLY TOXIC OR NONTOXIC: CAN BE APPLIED AT ANY TIME WITH REASONABLE SAFETY TO BEES. | |||
| Acequinocyl (Kanemite) |
Lime Sulfur (Lime Sulfur) |
||
| Aluminum tris O-ethyl phosphonate (Alliette, Fosetyl-Al) |
Mancozeb (Dithane, Gavel, Manzate, Penncozeb, Ridomil Gold MZ) |
||
| Azoxystrobin (Abound, Quadris) |
Mefenoxam (Maxim, Ridomil) |
|
|
| Bacillus subtilis (Rhapsody, Serenade, Cease) |
Laboratory tests suggest potential effects on bumble bees. | Metaldehyde bait (Deadline) |
|
| Bacillus thuringiensis (BT, Agree, Javelin, Thurcide) |
Metconazole (Quash) |
||
| Boscalid (Endura, Pristine) |
Methoxyfenozide (Intrepid) |
||
| Calcium Polysulfide (Lime Sulfur, Sulforix) |
Metrafenone (Vivando) |
||
| Captan (Captan, Captec, Captevate) |
Up to 7 day ERT for mason bees. Effects on honey bee brood in laboratory, but not in field tests. | Myclobutanil (Rally, Sonoma) |
No impact on bumble bees. |
| Chlorantraniliprole (Altacore, Coragen, Grubex) |
No impact on bumble bees. | Neem oil (Trilogy) |
Must be ingested to be toxic. |
| Chlorothalonil (Bravo, Echo) |
Tentatively associated with “entombed pollen”. Common contaminant of beeswax. |
Oils: Cottonseed, Clove, Garlic (Pest Out, GC-mite) |
|
| Clofentezine (Apollo) |
*Paraquat (*Paraquat) |
Although no PS on label, laboratory studies suggest effects on honey bee larvae, and paraquat has been associated with colony losses. | |
| Cyflufenamid (Miltrex, Torino) |
Penthiopyrad (Fontelis) |
||
| Cymoxanil (Tanos) |
Phosphorous acid, mono and di-potassium salts (Fosphite, Prophyt) |
|
|
| Cyprodinil (Switch, Vanguard) |
No impact on bumble bees. | Polyoxin D zinc salts (Oso, Ph-D, Tavano) |
|
| Dicofol (Dicofol) |
Mixing with insecticides increases hazard to bees. | Potassium bicarbonate (MilStop, Greencure, Kaligreen) |
No impact on bumble bees. |
| Difenoconazole (Inspire, Quadrus, Revus) |
Progargite (Omite) |
Mixing with insecticides increases hazard to bees |
|
| Dodine (Syllit) |
Propiconazole (Propicure, Quilt, Tilt) |
Mason bees more sensitive than honey bees. If mixed with lambda- cyhalothrin, may increase toxicity. | |
| Etoxazole (Zeal) |
3 days ERT for bumble bees | Pyraclostrobin (Cabrio, Pristine) |
|
| Famoxadone (Tanos) |
Pyrimethanil (Luna, Scala) |
||
| Fenarimol (Rubigan, Vintage) |
Pyriproxyfen |
≺2 hours RT for alfalfa leafcutting and alkali bees. May be toxic to bumble bee larvae. Avoid direct application or spray drift to honey bee hives (per label). No PS on label, other sources suggest ERT to bees. |
|
| Fenbuconazole (Indar) |
Quinoxyfen (Quintec) |
||
| Fenbutatin-oxide (Vendex) |
Reynoutria sachaliensis |
||
| Fenhexamid (Elevate) |
Spiromesifen (Oberon) |
Structure and mechanism of action similar to spirodiclofen and spirotetramat, which are potentially toxic to honey bee larvae. | |
| Fenpyroximate (Fujimite, Akari) |
Streptomyces lydicus (Actinovate) |
||
| Flonicamid (Beleaf) |
Possible effects on honey bees, further research needed. Short RT for alfalfa leafcutting bees and alkali bees. Short RT for bumble bees. |
Sulfur (various products OMRI classification varies by product) |
See also lime sulfur. While most sources say sulfur poses little risk for bees, other sources suggest sulfur may cause toxicity for bees for up to a day and a half. |
| Flubendiamide (Belt, Tourismo, Vetica) |
Possible effects on honey bee larval development, further research needed. | Tebuconazole (Adament, Luna, Orius) |
2 days ERT for bumble bees. |
| Fludioxonil (Switch) |
No impact on bumble bees. | Tebufenozide (Confirm) |
|
| Fluopicolide (Presidio) |
Tetraconazole |
1 day ERT for bumble bees | |
| Fluopyram (Luna) |
Thiacloprid (Calypso) |
Less toxic to bees than most other neonicotinoids. 1-2 days ERT for bumble bees. | |
| Hexythiazox (Onager, Savey) |
≻2 hours RT for alfalfa leafcutting and alkali bees | Thiophanate-methyl (Topsin-M) |
|
| Iprodione (Rovral) |
Laboratory studies suggest effects on honey bee larval development, field studies needed. | Triflumizole (Procure) |
May increase toxicity of certain neonicotinoids. |
| Kaolin Clay (Surround) |
Ziram (Ziram) |
Laboratory studies suggest effects on honey bee larval development, field studies needed. | |
| Kresoxim methyl (Sovran) |
|||
|
†Sources: 2010 New England Apple Pest Management Guide and Oregon State University Bulleting PNW591 ‘How to Reduce Bee Poisoning from Pesticides’. |
|||
| (SOURCE: 2010 THE MID-ATLANTIC BERRY GUIDE FOR COMMERCIAL GROWERS) | ||||||
|---|---|---|---|---|---|---|
| TOXICITY TO: | ||||||
| MITE PREDATORS | APHID PREDATORS | |||||
| PESTICIDE | BIRDS | FISH | BEES | N. FALLACIS | Z. MALI | |
| INSECTICIDES | ||||||
| Actara | Na | N | H | N | N | H |
| Admire | M | M | H | M | S | S-M |
| Asana | N | H | H | H | M | H |
| Aza-Direct | -- | H | N | -- | -- | S |
| Brigade/Capture | M | H | H | H | M | H |
| Confirm | S | H | M | N | N | N |
| Danitol | H | H | H | H | M | H |
| Diazinon | H | H | H | M | S | M |
| *Dibrom | -- | -- | M | -- | -- | -- |
| Dipel (B.t.) | N | N | N | N | N | N |
| Entrust/Spintor | H | -- | H | S | N | N |
| Esteem | -- | -- | N | S | N | N |
| Imidan | S | H | H | S | S | S |
| Lannate | H | H | H | H | M | H |
| *Lorsban | M | H | H | M | M | H |
| Malathion | M | H | H | S | -- | M |
| M-Pede | N | N | N | S | S | -- |
| Mustang Max | -- | H | H | H | M | H |
| Platinum | -- | M | -- | -- | -- | -- |
| Provado | M | M | H | S | S | M |
| Sevin XLR | S | N | H | M | M | M |
| *Thionex | H | H | S | S | N | M |
| MITICIDES | ||||||
| Acramite | -- | -- | H | M | M | S |
| AgriMek | N | N | H | H | M | -- |
| Kanemite | -- | Hb | -- | S | S | S |
| Kelthane/Dicofolc | M | H | N | H | S | S |
| Oberon | -- | H | -- | -- | -- | -- |
| Savey | -- | H | N | S | S | N |
| Vendex | M | M | N | M | M | H |
| Zeal | -- | -- | N | M | S | M |
|
a N = reasonably safe (for bees, apply anytime); S = slightly toxic (for bees, apply in evening after bees have stopped foraging until early morning before they start foraging); M = moderately toxic (for bees, apply in evening after bees have stopped foraging); H = highly toxic (for bees, do not apply to blooming plants); — = insufficient data *Restricted use pesticide; pesticide applicators license required. OMRI certified for organic production |
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