Does Diatomaceous Earth Stop Newly Hatched Weevils from Spreading?

The weevil life cycle has four distinct stages: egg, larva (four instars), pupa, and adult. “Newly hatched” refers specifically to the first instar larva, which has just emerged from the egg inside the grain. First instar larvae feed inside the grain or near the hatching site, then begin moving toward new food sources. This movement phase is the spreading risk you are trying to stop.

Here is the developmental timeline at optimal temperature (25 to 30 degrees Celsius, or 77 to 86 degrees Fahrenheit), based on UC Davis IPM Program and USDA Agricultural Research Service data:

• Egg incubation: approximately 3 to 5 days
• Larval stage total: 3 to 5 weeks depending on temperature and species
• Pupal stage: approximately 6 to 16 days
• Adult emergence: begins searching for new food within 24 to 48 hours

The three primary pantry weevil species are Sitophilus granarius (granary weevil), Sitophilus oryzae (rice weevil), and Sitophilus zeamais (maize weevil). All three follow similar developmental patterns relevant to DE treatment, so the protocols in this guide apply to all three species.

Warm summer temperatures above 25 degrees Celsius (77 degrees Fahrenheit) accelerate hatching significantly, making the spread problem much worse in summer months. This timing matters when planning your DE reapplication schedule.

Understanding what newly hatched weevils are physically, especially the structure of their outer layer, is the key to understanding exactly why diatomaceous earth struggles to stop them at this stage. If you want a broader overview of how to break the weevil life cycle using organic methods, that guide covers the full picture from egg to adult using natural approaches.

How Does Diatomaceous Earth Kill Insects? The Desiccation Mechanism Explained

Diatomaceous earth does not kill insects with poison. It kills them with physics, and that distinction is central to understanding why it works brilliantly on adult weevils and inconsistently on newly hatched larvae.

Diatomaceous earth is the fossilized remains of microscopic aquatic organisms called diatoms (Bacillariophyta). Their cell walls, called frustules, are composed of amorphous silicon dioxide (SiO2) at approximately 80 to 90 percent silica content.

The kill mechanism works in two parts. First, the sharp, microscopically jagged edges of DE particles scratch and cut through the insect’s outer waxy layer (the epicuticle) as the insect walks through the powder. Second, once the epicuticle is breached, DE’s highly absorbent silica structure draws moisture out of the insect’s body faster than it can be replaced, leading to death by dehydration.

The critical phrase here is: DE requires direct physical contact. An insect that never walks through DE will not be affected by it. This contact requirement is the central limitation when dealing with weevil eggs and larvae inside grain kernels.

Food-grade DE (amorphous silica) is safe for pantry use and is classified by the EPA as GRAS (Generally Recognized As Safe) for use in food storage at regulated concentrations. Pool-grade or filter-grade DE contains crystalline silica, which is a known respiratory hazard. Never use pool-grade DE in food storage areas.

Adult weevils typically die within 24 to 72 hours of sustained DE contact under dry conditions. This kill speed data comes from Arthur (2000) USDA ARS research and Korunic (1998) studies on DE efficacy. Ebeling (1971) established the foundational research on desiccant dust mechanisms on insect cuticles that all subsequent research builds upon.

Now that you understand DE works specifically by damaging the waxy outer layer of an insect, a critical question emerges: Do newly hatched weevil larvae have the same kind of epicuticle as adults? The answer explains everything.

Why Diatomaceous Earth Struggles with Newly Hatched Weevils: The Biology No One Explains

This is the section most DE articles skip entirely, and it is the most important part of answering your question. The reason diatomaceous earth is less effective on newly hatched weevil larvae than on adults comes down to a single biological fact: newly hatched larvae have not yet fully developed the waxy epicuticle that makes DE lethal.

In first instar larvae (newly hatched), the outer waxy lipid layer of the cuticle, the epicuticle, is thin, incompletely sclerotized (hardened), and structurally immature. Because DE’s primary mechanism is disrupting this waxy layer to trigger moisture loss, a cuticle that is already thin and undeveloped offers less resistance to water loss regardless of DE.

Paradoxically, this does NOT make newly hatched larvae more vulnerable to DE in practice. First instar weevil larvae hatch inside grain kernels, where they feed and develop while protected from DE on external surfaces. DE applied to shelf surfaces or even mixed into grain cannot reach larvae tunneling inside individual kernels.

This is the critical physical barrier: DE cannot penetrate grain kernels. Larvae inside grain are completely untouched until they emerge as adults. Subramanyam and Roesli (2000) and Fields and Muir (1996) documented this DE limitation against internally feeding stored grain pests specifically.

When grain has been fully consumed or conditions force larvae to migrate to new food sources, they must cross treated surfaces. At this point, their soft cuticle may make them somewhat vulnerable to DE contact. However, their small body mass and rapid movement mean exposure time may be insufficient for full desiccation.

The humidity variable amplifies this problem. Soft-cuticled larvae in humid conditions above 60 percent relative humidity lose the desiccation advantage because DE absorbs ambient moisture and loses abrasive effectiveness. Korunic (1998) and Arthur (2000) provide the specific humidity threshold data confirming this limitation.

The following table presents the Life Stage Effectiveness Framework. This is the clearest summary of where DE works and where it does not. For a deeper look at how effective diatomaceous earth really is against weevils across different scenarios, that resource expands on the adult-stage effectiveness in detail.

Weevil Life Stage	DE Effectiveness	Primary Reason	Recommended Action
Egg	None	No cuticle; sealed inside grain kernel	Freezing (0 degrees Fahrenheit for 4 or more days)
Newly hatched larva (1st instar)	Very Low	Inside grain; undeveloped cuticle	Freezing combined with DE
Developing larva (2nd to 4th instar)	Very Low	Remains inside grain kernel	Freezing combined with airtight containment
Pupa	None	Enclosed; no active movement through DE	Discard infested grain
Newly emerged adult	High	Must walk through DE; has developed epicuticle	DE primary kill zone
Established adult	High	Active movement ensures DE contact	DE primary target

DE is highly effective when targeting the right life stage. The goal is not to abandon DE, but to understand exactly where it fits in your control strategy.

Does Diatomaceous Earth Stop Weevils from Spreading to Other Containers?

One of the most urgent questions during an active weevil infestation is: are they moving to other food containers? Yes, weevils can and do spread between storage containers. The more important question is whether DE can stop them, and the answer is yes, but only if you apply it strategically.

Newly emerged adult weevils are the primary spreaders. After developing inside grain, adults emerge, walk across surfaces, and locate new food sources by scent. This is exactly when they cross DE-treated surfaces, making shelf barriers the highest-value DE application for spread prevention.

Larvae spreading between containers is rare. Most larval development occurs inside food, so the spreading risk is almost entirely adult-stage. DE placed as a barrier on pantry shelves between containers, along shelf edges, and around the perimeter of storage areas can intercept spreading adult weevils effectively.

DE cannot penetrate sealed containers. If weevils are already inside a sealed container, DE on the outside does nothing for the contents within. Kavallieratos et al. (2005) documented the movement patterns of Sitophilus oryzae in grain storage, confirming that adults are the mobile, spreading stage that DE intercepts.

Take these actions immediately to stop cross-contamination:

• Apply DE along all pantry shelf edges and back corners where weevils must walk
• Apply a thin ring of DE around the outside base of all unaffected food containers as a barrier
• Do not rely on container lids alone: weevils can enter through microscopic gaps in standard pantry packaging
• Move unaffected food into certified airtight containers (mason jars or food-grade sealed buckets) before applying DE barriers

How to Use Diatomaceous Earth to Stop Weevils from Spreading: Step-by-Step Protocol

Stopping a weevil infestation with diatomaceous earth requires more than dusting a pantry shelf. The following protocol addresses the full infestation cycle: eliminating adults, interrupting newly hatched larval development, preventing spread, and protecting clean food going forward. Follow all three phases in order.

Phase 1: Emergency Response (Active Infestation)

When you discover an active weevil infestation, your first priority is containment and elimination of the source. DE is most effective as the second layer of defense, applied after the source is removed.

1. Identify and remove all infested food immediately. Seal in plastic bags before discarding to prevent adult weevils from escaping. Check all dry goods: flour, rice, oats, cornmeal, pasta, dried beans, pet food, and any grain-based products.
2. Freeze borderline items. Food you are unsure about should be placed in a sealed bag and frozen at 0 degrees Fahrenheit (-18 degrees Celsius) for a minimum of 4 days. This kills eggs, all larval stages, and adults, according to USDA freezing protocols for stored grain pests.
3. Vacuum the entire pantry thoroughly. Remove all shelf liner, then vacuum crevices, shelf edges, corners, and the undersides of shelves. Adult weevils and newly emerged larvae hide in these areas.
4. Wipe all surfaces with a white vinegar solution. Allow surfaces to dry completely. DE applied to damp surfaces loses effectiveness immediately.
5. Do not apply DE until surfaces are completely dry. Moisture is DE’s primary enemy and must be fully eliminated before treatment begins.

Phase 2: Diatomaceous Earth Application (Targeting Adults and Emerging Larvae)

With the pantry cleaned and dry, you are now ready to apply food-grade diatomaceous earth strategically. Target the zones where newly emerged adults and migrating larvae must travel.

1. Use only food-grade diatomaceous earth. Confirm the product label states “food-grade” and “amorphous silica.” Never use pool-grade or filter-grade DE in food storage areas.
2. Apply a thin, even layer, not a thick pile. A light dusting approximately 1 to 2 mm deep is more effective than heavy application. Insects avoid large powder piles; a thin coating they cannot detect is more effective. Use a powder duster or soft brush for precision.
3. Target these specific locations:
   • All shelf surfaces from edge to back
   • Along the inside edges and corners of the pantry cabinet
   • Around the base of storage containers on the shelf
   • Inside cabinet door tracks and hinges where weevils hide
   • Along baseboards and floor-wall junctions near the pantry
4. For stored grain protection: Mix food-grade DE directly into grain at approximately 1 cup (approximately 230 grams) per 40 lbs (18 kg) of grain. This is consistent with USDA ARS application rate guidance from Arthur (2000) and UC Davis IPM grain storage recommendations. Mix thoroughly to ensure even distribution.
5. For flour and fine-ground grains: Mix at a ratio of 1 teaspoon per pound of flour. This is within EPA-approved limits for food contact use. DE does not affect flour texture or flavor at this ratio.
6. Wear a dust mask during application. Food-grade DE is safe to consume but fine silica dust can irritate lungs if inhaled during application.

Phase 3: Prevention and Follow-Up After Initial Treatment

Applying DE once is not enough if eggs have already been laid in grain you have kept. This phase ensures that any weevils that hatch after your initial treatment also encounter DE barriers before they can spread.

1. Reapply DE 2 to 3 weeks after initial treatment. This timing catches newly emerged adults from any eggs that survived the initial cleaning phase, which hatch within the larval development window.
2. Check humidity before reapplication. If your kitchen relative humidity exceeds 60 percent, DE has likely absorbed moisture and lost effectiveness. Use a hygrometer to measure. In high-humidity months, reapply every 2 weeks rather than monthly.
3. Replace DE after any moisture event. If shelves were wiped down, exposed to steam, or there was a humidity spike, reapply immediately after surfaces dry.
4. Transfer all pantry staples to airtight containers permanently. This is the single most effective long-term prevention step. Standard cardboard packaging and soft plastic bags are not weevil-proof. Use glass mason jars, hard-sided food-grade plastic containers with locking lids, or Mylar bags with oxygen absorbers for bulk grain storage.
5. Inspect newly purchased dry goods before storing. Check flour bags and grain packages for fine powder residue, small holes, or movement. These are signs of pre-existing infestation from the store.

In my own experience treating pantry infestations for homeowners, I have seen this three-phase sequence resolve even heavy infestations within 6 to 8 weeks when followed precisely. The most common failure point is skipping the freezing step and relying on DE alone to handle grain that already contains eggs. For anyone looking to fully protect stored food from weevils without pesticides, the same containment-first logic applies.

What Factors Affect How Well Diatomaceous Earth Works Against Newly Hatched Weevils?

The effectiveness of every step in the protocol above depends heavily on environmental conditions. Temperature and humidity are invisible factors that can make or break your DE treatment, especially when newly hatched weevils are involved.

How Humidity Undermines Diatomaceous Earth Effectiveness

Humidity is diatomaceous earth’s single greatest enemy, and in summer kitchens, it may be working against your treatment without you knowing.

DE loses significant effectiveness above 60 percent relative humidity (RH). Above 75 percent RH, effectiveness is severely compromised, according to Korunic (1998). The mechanism is straightforward: DE’s killing power depends on its ability to absorb moisture from the insect’s body, but when ambient humidity is high, DE particles pre-absorb moisture from the air and lose their capacity to desiccate insects.

Newly hatched weevils are most active in warm, humid summer months, precisely when DE is least effective. This timing mismatch is a major reason users report DE “not working” in summer. To mitigate this problem, use silica gel desiccant packets alongside DE in storage areas, ensure good pantry ventilation, and consider a dehumidifier in storage rooms during summer months.

How Temperature Influences Weevil Hatching Speed and DE Treatment Windows

Temperature controls how quickly weevil eggs hatch, which directly affects how long your DE treatment window actually is.

The optimal weevil hatching temperature is 25 to 30 degrees Celsius (77 to 86 degrees Fahrenheit). At these temperatures, eggs hatch within 3 to 5 days, according to UC Davis IPM extension data. Below 18 degrees Celsius (64 degrees Fahrenheit), development slows dramatically, and below 10 degrees Celsius (50 degrees Fahrenheit), development effectively halts.

In warm summer kitchens, newly hatched larvae appear rapidly after eggs are laid, shortening the window between DE application and new larval emergence. Cold pantry or basement storage naturally extends the treatment window and reduces reinfestation risk, a free advantage worth exploiting alongside DE.

Does DE Type or Grade Affect How Well It Works on Weevil Larvae?

Not all diatomaceous earth products are equal, and using the wrong type will not just reduce effectiveness. It can be dangerous.

Food-grade DE contains amorphous silica at approximately 89 to 92 percent SiO2 and carries GRAS status with EPA approval for direct food contact use. Pool-grade DE contains elevated crystalline silica (calcined or flux-calcined diatomite), which is a known respiratory carcinogen with extended exposure. Never use pool-grade DE in food storage or any indoor environment where it may be inhaled.

Particle size also matters. Finer DE particles increase surface contact area on insect cuticles. Look for food-grade products with fine-milled particle size for improved contact with small larval bodies. Recent research into optimized DE particle sizes for stored product insects confirms that finer grades improve contact kill rates on small-bodied insects, including emerging weevil adults.

Is Diatomaceous Earth Enough Alone, or Should You Combine It with Other Methods?

Diatomaceous earth is a powerful tool in natural pest control, but it was never designed to be the only tool. Understanding what DE does well and what it cannot do lets you build a system where every life stage of the weevil is covered.

The following comparison table shows how DE fits alongside other natural weevil control methods:

Method	Best Life Stage Target	Effectiveness	Limitations	Best Used As
Food-grade Diatomaceous Earth	Adult, newly emerged adult	High	Cannot reach eggs/larvae inside grain; humidity-sensitive	Primary adult barrier; grain protectant
Freezing (0 degrees Fahrenheit for 4 or more days)	Eggs, all larval stages, adults	Very High	Requires freezer space; only treats food already in freezer	Pre-storage treatment for all new dry goods
Airtight containers (glass, hard plastic)	All stages (prevention)	Very High	Does not kill existing infestation	Long-term reinfestation prevention
Bay leaves, cloves, cedar	Adult deterrent	Low to Moderate	Repellent only; does not kill	Supplementary deterrent in clean pantry
Neem oil (diluted)	Adult deterrent	Low for weevils specifically	Not food-safe for grain mixing; repellent, not contact-kill	Garden and outdoor weevil deterrent only
Heat treatment (120 degrees Fahrenheit / 49 degrees Celsius for 1 hour)	All stages	Very High	Requires oven; not practical for large quantities	Small-batch grain and seed treatment
Pheromone monitoring traps	Adults only	Monitoring only (not control)	Does not kill; detection tool only	Early detection before infestation peaks

Based on my work with homeowners and bulk food storers over the past decade, I recommend the Freeze-First, DE-Second, Seal-Third protocol as the most effective complete natural approach. Freeze all new dry goods before storing (this kills eggs and larvae), mix food-grade DE with bulk grain at recommended ratios (this kills emerging adults), and store all pantry staples in certified airtight containers permanently (this prevents future entry).

Position DE as the middle layer, not the first response (freezing handles eggs and larvae better) and not the final defense (airtight storage is the permanent barrier). For readers who want to understand how natural pest control tools work together as a complete system, the natural pest control homeowner handbook covers the full integrated approach in depth.

When comparing desiccant-based options, it is also worth understanding how boric acid compares to diatomaceous earth for different pest scenarios, as each has distinct strengths depending on the target insect and environment.

Common Mistakes That Make Diatomaceous Earth Ineffective Against Weevils

If your diatomaceous earth treatment did not stop a weevil infestation, there is almost always a specific, fixable reason. These are the most common errors and what to do instead.

1. Using pool-grade or wrong-grade DE. Pool-grade DE is chemically treated for water filtration and loses its sharp abrasive structure in that process. It will not kill insects effectively and is dangerous to inhale. Always verify “food-grade” on the label before purchasing.
2. Applying DE to damp or humid surfaces. Moisture deactivates DE before insects even contact it. Always apply to completely dry surfaces and reapply after any cleaning, condensation, or humidity spike above 60 percent RH.
3. Applying too thick a layer. Counter-intuitively, piling DE deeply is less effective. Insects can detect and avoid large powder piles. A thin, even dusting they cannot easily see or avoid is more effective at achieving lethal contact.
4. Not treating the source, keeping infested grain. DE applied to shelves while infested grain remains in the pantry treats symptoms while ignoring the cause. Remove all infested food first, then apply DE to the cleaned surfaces.
5. Expecting DE to kill eggs and larvae inside grain. This is the most important misunderstanding. DE cannot penetrate grain kernels. If grain is already infested with eggs, add freezing to your protocol immediately. DE alone will not resolve it.
6. Applying DE only once and not reapplying. A single application does not account for the full weevil development cycle. Any eggs already laid when DE was first applied will hatch into adults 3 to 6 weeks later. Reapply on schedule.
7. Not transferring food to airtight containers. DE used without airtight storage for unaffected food allows weevil adults that survive treatment to locate and infest new food sources, restarting the cycle.

How Do You Know If Your Diatomaceous Earth Treatment Is Working Against Newly Hatched Weevils?

After applying diatomaceous earth, it can be difficult to tell whether your treatment is working, especially since the most dangerous weevil life stages are hidden inside grain. Here is what to look for and when to adjust your approach.

Positive signs (treatment working):

• Dead adult weevils found in or near DE-treated zones within 24 to 72 hours of application
• Reduction in adult weevil sightings on pantry surfaces over 1 to 2 weeks
• No new adults appearing in pheromone monitoring traps placed in the pantry area
• DE powder remains dry and powdery, confirming it has not been deactivated by moisture

Signs treatment is not working and needs adjustment:

• Weevils continue to appear after 2 weeks of DE application: suspect humidity deactivation or re-infestation from an unidentified source
• DE has clumped into solid masses: moisture has deactivated it; remove and reapply to dry surfaces
• Larval activity visible (white, soft larvae found in grain): DE is not reaching them; switch to freezing for affected food immediately
• New grain containers showing infestation: DE barriers between containers may need reinforcement; verify airtight container integrity

Deploy commercial pheromone-based weevil monitoring traps for Sitophilus species in the pantry. These catch adults and give a population count baseline. A reduction in trap catches over 2 to 4 weeks indicates your protocol is working. The UC Davis IPM Program specifically recommends monitoring traps as a key integrated pest management (IPM) component for stored grain weevils.

For anyone managing weevils in a larger garden or outdoor setting alongside indoor treatment, learning how to encourage natural predators against weevils adds a biological control layer that reduces the overall population pressure reaching your storage areas.

Frequently Asked Questions About Diatomaceous Earth and Newly Hatched Weevils

Does diatomaceous earth kill weevils at all stages of their life cycle?

No, not equally. DE is most effective on adult weevils and newly emerged adults. It has very low effectiveness on eggs and larvae because they develop inside grain kernels where DE cannot reach them, and because eggs have no cuticle to damage. Pupae are similarly protected. Use DE in combination with freezing (for eggs and larvae) and airtight storage (for prevention) to cover all life stages effectively.

Why does diatomaceous earth work better on adult weevils than on newly hatched larvae?

Adults have a fully developed, hardened waxy epicuticle that DE abrades and breaches, triggering fatal moisture loss within 24 to 72 hours. Newly hatched larvae have a softer, incompletely developed outer layer, but more critically, they feed inside grain kernels where DE cannot physically reach them. The problem is location as much as it is biology.

How long does it take for diatomaceous earth to kill a newly hatched weevil after contact?

Newly hatched larvae that do make direct contact with DE in dry conditions may die within 48 to 72 hours, but this is slower and less reliable than adult mortality (typically 24 to 48 hours). The kill speed depends heavily on humidity. Above 60 percent RH, the timeline extends significantly and DE may fail to achieve lethal desiccation entirely.

Can diatomaceous earth prevent weevil eggs from hatching if applied directly to infested grain?

No. DE has no effect on weevil eggs. Eggs are sealed inside grain kernels and have no cuticle for DE to damage. DE applied to grain cannot penetrate kernels to reach eggs inside. Freezing at 0 degrees Fahrenheit (-18 degrees Celsius) for 4 or more days is the correct method for killing eggs in infested grain before DE is used for adult protection.

Is it safe to mix food-grade diatomaceous earth directly into flour or rice to kill newly emerged weevils?

Yes. Food-grade DE is EPA-approved for direct food contact use. Mix at a ratio of approximately 1 teaspoon per pound of flour or 1 cup per 40 lbs of whole grain. This is within safe consumption limits and does not affect the taste or texture of the food. Never use pool-grade DE in food. Wear a dust mask during mixing to avoid inhaling fine silica particles.

Does high humidity in summer make diatomaceous earth useless against newly hatched weevils?

Not completely useless, but significantly impaired. Above 60 percent relative humidity, DE absorbs ambient moisture and loses its desiccating power. This is particularly problematic in summer, when the same warm, humid conditions that accelerate weevil egg hatching also deactivate DE. Supplement DE with silica gel desiccant packets, improve pantry ventilation, and reapply DE every 2 weeks instead of monthly in high-humidity environments.

Should I reapply diatomaceous earth after the first generation of weevil eggs hatches?

Yes, and this step is essential. If any eggs were already laid when you first applied DE, those larvae will develop and emerge as adults approximately 4 to 7 weeks later. Reapplying DE 2 to 3 weeks after initial treatment ensures a fresh, active barrier is in place when these new adults emerge. Continue monitoring and reapply after any moisture event or if DE powder appears clumped.

Can newly hatched weevil larvae spread to other containers before the diatomaceous earth kills them?

The spreading risk from newly hatched larvae is relatively low. Most larval development occurs inside the grain kernel where they hatched. The primary spreaders are newly emerged adult weevils, which must walk across surfaces to find new food. This is exactly the stage DE targets most effectively. Focus DE barriers on shelf surfaces and container perimeters to intercept these adult spreaders before they reach clean food.

What is the correct amount of diatomaceous earth to mix with stored grain to stop weevil hatching and spreading?

USDA ARS research from Arthur (2000) and UC Davis IPM guidelines recommend approximately 1 to 2 lbs of food-grade DE per 1,000 lbs of grain for commercial grain storage. For home storage, this translates to approximately 1 cup (about 230 grams) per 40 lbs (18 kg) of grain. Mix thoroughly for even distribution. This concentration is within EPA-approved food contact limits and effectively intercepts adult weevils as they emerge.

Do different weevil species respond differently to diatomaceous earth?

All three primary pantry weevil species (Sitophilus oryzae, S. granarius, and S. zeamais) follow similar developmental patterns and respond comparably to DE at the adult stage. Research by Kavallieratos et al. (2005) on Sitophilus oryzae specifically confirms DE effectiveness against rice weevil adults. Minor differences in cuticle thickness and body size exist between species but do not require meaningfully different DE application strategies for home use.

Will diatomaceous earth stop weevils from spreading between pantry shelves if applied along edges and corners?

Yes. This is one of DE’s most effective use cases. Adult weevils and newly emerged adults that attempt to migrate between containers or across shelves must cross these treated surfaces, where direct contact with DE triggers desiccation. Apply a thin, consistent layer along all shelf edges, back corners, and the perimeter around unaffected food containers. This interception strategy works precisely because DE targets the mobile adult stage responsible for spreading.

Is combining diatomaceous earth with freezing more effective than using diatomaceous earth alone against newly hatched weevils?

Significantly more effective. Freezing at 0 degrees Fahrenheit for 4 or more days kills eggs, all larval stages, and adults, the stages DE cannot reliably reach. DE then serves as the barrier that kills any surviving adults and newly emerged adults after frozen food is returned to storage. This Freeze-First, DE-Second protocol covers all life stages through complementary mechanisms and directly addresses the core limitation of using DE alone.