MOSQUITO DUNKS Biological Larvicide 2-Pack (20 Tablets) — EPA-Registered Bti, Up to 30-Day Control

MOSQUITO DUNKS Summit #111-5 is a biological larvicide sold as a two-pack of 20 tablets that targets mosquito larvae in standing water without harming fish, pets, or plants.

If you need a simple, EPA-registered way to reduce mosquito populations around yards, ponds, birdbaths, gutters, and other stagnant water, these Summit mosquito dunks deliver targeted control using Bacillus thuringiensis israelensis (Bti). Each dunk works where adult sprays can’t reach—inside breeding sites—breaking the mosquito life cycle by killing larvae before they become biting adults. The product comes as donut-shaped solid tablets that slowly release the active ingredient over days to weeks depending on water conditions.

How do these dunks work and how long do they last?

The dunks release Bti, a naturally occurring bacterial toxin that is lethal to mosquito larvae when ingested but safe for humans, pets, wildlife, and most aquatic organisms. A single dunk typically provides effective control for 30 days indoors or outdoors under normal conditions. In fast-moving or highly diluted water the residual activity is shorter, so placement matters for best results.

• Active ingredient: Bacillus thuringiensis israelensis (Bti)
• Typical control duration: up to 30 days per dunk
• Works in stagnant or slow-moving water where larvae hatch
• Safe for fish and beneficial insects when used as directed

Where should I place the dunks for maximum effectiveness?

Place dunks wherever water collects and remains still long enough for mosquito larvae to develop—this includes birdbaths, rain barrels, clogged gutters, pond edges, storm drains, and wheelbarrows. Use one dunk for about 100 square feet of surface or as directed on small containers; larger bodies of water will need proportionally more dunks spaced across the area. Avoid placing dunks in frequently flushed or rapidly flowing water, which washes away the active ingredient.

• Ideal sites: birdbaths, ponds, rain barrels, tires, planters, gutters
• One dunk treats roughly 100 sq ft surface or one small container
• Replace monthly or after heavy rain if material is depleted
• Not effective in fast-flowing drains or streams

Is this product safe for pets, fish, and beneficial wildlife?

MOSQUITO DUNKS use a biological agent that specifically targets dipteran larvae, making them safe for most non-target animals when used according to the label. Because Bti must be eaten by larvae to be effective, it does not pose the same toxicity risks as broad-spectrum chemical insecticides. For sensitive or ornamental aquatic species, always follow label precautions and avoid overdosing confined tanks or aquaria.

• Designed to be safe for fish, birds, pets, and beneficial pollinators
• Non-repellent: reduces larvae without harming adult wildlife
• Use label directions for small or enclosed water features
• Minimal environmental impact compared with chemical sprays

How do I use and store the product properly?

Handle the dunks with dry hands or gloves and place them directly into standing water where larvae develop; they may crumble if crushed but remain effective. Replace each dunk approximately every 30 days or sooner after heavy rainfall that significantly dilutes activity. Store unused dunks in a cool, dry place away from direct sunlight and out of reach of children and pets.

• Apply directly to standing water—no mixing required
• Replace monthly or after extreme dilution events
• Store in cool, dry, shaded area per label instructions
• Wash hands after handling and keep away from children

Who is this for: MOSQUITO DUNKS Summit #111-5 (20 count, two-pack) is ideal for homeowners, gardeners, pond-keepers, property managers, and anyone who wants a low-effort, targeted approach to reduce mosquito breeding on their property. It’s useful for seasonal maintenance, vacation properties, or year-round control in regions with persistent standing water. If you prefer biological solutions over chemical sprays and need a product that treats hidden breeding spots safely and effectively, this dunk pack is a practical option.