3.3 Non-Target & Pollinator Protection

Non-Target & Pollinator Protection

Pesticides applied in agricultural, urban, and right-of-way settings can inadvertently cause severe harm to non-target organisms, including pollinators, beneficial predatory insects, fish, birds, and endangered desert wildlife. Protecting non-target species is both an ecological priority and a strict legal mandate under Nevada pesticide statutes and federal environmental laws. Certified applicators must evaluate non-target hazards prior to every application and implement rigorous mitigation measures.

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Honey Bee & Wild Pollinator Protection

Pollinators contribute hundreds of millions of dollars to agricultural ecosystems. In Nevada, managed European honey bees (Apis mellifera) and specialized native pollinators—such as alkali bees (Nomia melanderi), alfalfa leafcutter bees (Megachile rotundata), and desert bumblebees (Bombus spp.)—are essential for producing commercial alfalfa seed, onion seed, melons, fruit crops, and maintaining wild desert vegetation.

Routes of Pollinator Exposure

Bees are exposed to pesticides through several pathways during foraging:

• Direct Contact: Contact with spray droplets or dust clouds when applications occur while bees are actively foraging in the field.
• Foliar Residue Contact: Walking across treated plant leaves, petals, or stems containing toxic chemical residues.
• Ingestion: Consuming contaminated nectar, pollen, guttation fluid (water droplets secreted by plant leaves), or surface puddles contaminated with runoff/drift.
• Hive Contamination: Foragers carrying contaminated pollen or nectar back to the colony, resulting in broad hive mortality, brood death, or long-term queen failure.

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Managed Pollinator Protection Plans (MP3)

To address pollinator decline while maintaining effective agricultural pest control, Nevada established its Managed Pollinator Protection Plan (MP3), coordinated by the Nevada Department of Agriculture (NDA).

Key Components of Nevada's MP3 Framework

1. Apiary Mapping & Beekeeping Registry: Commercial beekeepers register their hive locations annually with the NDA. Applicators use spatial mapping databases to locate apiaries within their application zones.
2. Mandatory Pre-Application Notification (NAC 555.470): Before applying any pesticide known to be harmful to bees to commercially grown agricultural or horticultural crops, a licensee must notify every apiarist with bees on the land to be treated or on adjacent land, so the apiarist can protect the hives. The notice must be given not more than 72 hours and not less than 24 hours before the application to each apiarist having apiaries within 2 miles of the field to be treated; it must state the name of the person for whom the application is made, the location and acreage of the land, and the pesticide to be applied; and it may be delivered personally, by telephone, or by electronic mail. If the application is postponed after proper notice, the licensee must repeat the notice at least 12 hours before the rescheduled application. No notice is required if the apiarist has not provided current apiary location information.
3. Application Timing Restrictions: Applicators must schedule treatments during hours when pollinators are not foraging:
   • Night Spraying: Applying pesticides between late evening (after sunset) and early morning (before sunrise) allows foliar residues to dry before bees resume foraging at dawn.
   • Temperature Thresholds: Foraging activity drops significantly when ambient temperatures drop below $55^\circ\text{F}$.
4. Blooming Crop Restrictions: Pesticides with high bee toxicity must NEVER be applied to crops, weeds, or cover crops in bloom. Orchard floors and field borders containing blooming weeds (e.g., dandelions, mustard) must be mowed prior to pesticide application.

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Toxicity Ratings & Label Hazard Statements

The EPA evaluates pesticide toxicity to adult honey bees using acute contact oral laboratory assays, reporting the Median Lethal Dose ($LD_{50}$) in micrograms per bee ($\mu\text{g/bee}$).

EPA Bee Toxicity Categories

• Highly Toxic ($LD_{50} < 2.0,\mu\text{g/bee}$): Kills bees on contact or short exposure. Includes neonicotinoids (imidacloprid, thiamethoxam, clothianidin), organophosphates (chlorpyrifos, dimethoate), and synthetic pyrethroids. Labels carry mandatory warning boxes with the EPA Bee Icon.
• Moderately Toxic ($LD_{50} = 2.0\text{--}11.0,\mu\text{g/bee}$): Toxic to bees; applications should be restricted to times when bees are not actively foraging.
• Relatively Non-Toxic ($LD_{50} > 11.0,\mu\text{g/bee}$): Can be applied with minimal hazard to pollinators when used according to label directions.

                         EPA POLLINATOR PROTECTION BOX
      +-----------------------------------------------------------------+
      |   [ BEE ICON ]  PROTECTION OF POLLINATORS                       |
      |   APPLICATION RESTRICTIONS EXIST FOR THIS PRODUCT BECAUSE OF    |
      |   HIGH TOXICITY TO BEES AND OTHER POLLINATING INSECTS.         |
      |   - Do not apply this product while bees are foraging.          |
      |   - Do not apply to plants in bloom.                            |
      |   - Minimize drift to blooming weeds in field margins.          |
      +-----------------------------------------------------------------+

Formulation Risks

The physical formulation of a pesticide significantly influences pollinator hazard:

• Microencapsulated Formulations (Highest Hazard): Microscopic plastic polymer capsules containing liquid pesticide are identical in size ($10\text{--}50,\mu\text{m}$) to natural pollen grains. Foraging bees collect these capsules, store them in pollen baskets, and carry them directly back to the hive, causing catastrophic colony collapse.
• Dusts (D) and Wettable Powders (WP): Highly hazardous; dust particles cling to electrostatic bee body hairs.
• Emulsifiable Concentrates (EC) and Granules (G): Present significantly lower hazard to bees because liquid EC formulations dry rapidly into leaves, and soil-applied granules avoid foliar contact.

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Nevada Wildlife Safeguards: Desert Tortoise & Sage-Grouse

Nevada's desert ecosystems harbor specialized threatened and endangered wildlife species that require rigorous protection during pesticide applications.

1. Desert Tortoise (Gopherus agassizii)

The Desert Tortoise inhabits Mojave Desert ecosystems across southern Nevada (Clark, Lincoln, and Nye Counties).

• Threats: Ingestion of toxic rodenticide baits, direct exposure to non-selective herbicides that destroy native forage plants, and herbicide contamination of desert burrows.
• Safeguards: Applicators operating in Desert Tortoise habitat must use tamper-resistant bait stations for rodent control, avoid spraying near active burrow entrances, and strictly adhere to EPA Endangered Species Protection Bulletins.

2. Greater Sage-Grouse (Centrocercus urophasianus)

The Greater Sage-Grouse relies on expansive sagebrush (Artemisia) steppe habitats across northern and central Nevada.

• Brood-Rearing Habitat Safeguards: Sage-grouse chicks depend entirely on high-protein insects (ants, beetles, caterpillars) for survival during their first 4 to 10 weeks of life.
• Broad-spectrum insecticide applications in sage-grouse brood-rearing habitats deplete insect food sources, causing chick starvation.
• Herbicide applications that eradicate native sagebrush or broadleaf forbs destroy essential sage-grouse food and nesting cover.

EPA Bulletins Live! Two Compliance

To fulfill federal Endangered Species Act (ESA) requirements, Nevada applicators are legally required to access the EPA's Bulletins Live! Two online database prior to applying pesticides. If an applicator's target site falls within a designated Endangered Species Protection Bulletin area, the applicator must follow all geographic buffer zone restrictions and seasonal use prohibitions published in the bulletin.