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What is fumigation?

Fumigation is a method using gas (fumigant) to exterminate pests in commodities within an enclosed space such as tarpaulin-covered shipments, ship’s holds, barges, silos, container, etc.

Why is fumigation important?

According to the regulations of the phytosanitary agencies, commodities in general, especially agricultural products, need to be fumigated before being exported to avoid the spread of harmful organisms from foreign countries as well as country to country to protect the commodities from damage caused by insects. A fumigation certificate is often required in trading contracts of imported and exported goods.

What commodities usually need to be fumigated before export?

Agricultural products in general (rice, coffee, cassava chips, spices such as pepper, ginger, cinnamon, edible nuts such as cashews, almonds, etc.)
Products made from wood, handicraft items, commodities with wood dunnage such as pallets, shelves, lifting plates, etc.

What chemicals used for fumigation?

Currently, in the world there are quite a few chemicals used as insecticides, however, of which only 2 chemicals are most commonly used and accepted in most countries are Methyl Bromide (CH3Br) and Aluminum Phosphide (AlP) – the starting ingredient to make Phosphine gas (PH3). Both of these chemicals – Methyl Bromide and Phosphine affect insects in a gaseous state, after the necessary incubation time, the vapor is vented out of the fumigated space so that the commodities can be used as required.

What chemicals does VFC use for spraying?

We will use the appropriate chemicals depending on the locations/areas that need spraying and what commodities are stored inside. Currently, in the list of pesticides permitted by the Ministry of Agriculture and Rural Development, only Actellic 50EC (active ingredient Pirimiphos - methyl) is suitable for spraying insecticides in commodities storage and factories.

Insects enter commodities through which ways?
  • Already exist on merchandise.
  • Capable of moving from one area to another by flying, or crawling.
  • Infection through the transportation of commodities, from people, birds, rats, etc.
  • Infection through the transportation of commodities, from people, birds, rats, etc.

There are many ways for insects to enter commodities. Fully understanding how the infection happened helps us to have the most effective insect control measures.

How many stages of development do insects have? What stages of development are difficult to kill?

Pests generally belong to the Coleoptera and Lepidoptera group, their life cycle goes through four stages of development: egg - larva - pupa - adult, in which the egg and pupa stages are the most difficult to kill. Therefore, when fumigating, it is necessary to pay attention to technical solutions to not only kill adult insects but also exterminate all stages of insect development.

Why must there be a special control when commodities are infected with insects that are subject to quarantine?

Insects that are subject to quarantine are species that can grow, cause great damage, and have never appeared or appeared only in small areas in a country. These insects are a very big threat to a country's agriculture. Therefore, when detected, the phytosanitary agency will have to carry out very strict control measures (zoning, isolating, fumigating, disinfecting, spraying, etc.) to thoroughly eradicate the nests, prevent the infection from spreading to other areas, and continue to have a monitoring mechanism for a necessary period.

Incubation time required for each fumigant?

For insects to be exterminated, the vapor needs to act on the insect for a long enough time with a certain necessary concentration level (C x T). In order to thoroughly exterminate all stages of insect development, the required incubation time for Methyl Bromide must be at least 24 hours or more, and for Aluminum Phosphide, it must be at least 120 hours because of the nature of the gas which is slow acting on insects. Aluminum Phosphide itself is not an insecticide but will release Phosphine gas (PH3) from the reaction:

AlP + 3H2O = PH3 + Al(OH)3

Why does wooden dunnage (pallets, racks, etc.) have to be fumigated and stamped before export?

Commodities imported and exported from one country to another are always subject to insect control based on the Phytosanitary regulation and the requirements in the import and export contract. However, the accompanying wood dunnage (pallets, racks, etc.) is usually not of interest for insect inspection, and the exact origin of this wood dunnage is unknown (because of the reuse) leading to the spread of pests from one country to another. The IPPC (International Plant Protection Convention) has issued the ISPM 15 (International Standards for Phytosanitary Measures) standard, which stipulates that these materials must be fumigated to kill pests before using to pack export commodities.

According to ISPM 15, what insect control measures are acceptable?

As specified by ISPM 15 standard, Wood Packaging Materials must be fumigated with Methyl Bromide or Heat Treated with the temperature in the core of the wood must reach a minimum of 56°C for some time. The minimum time is 30 minutes. Accompanying the treatment, these wooden packaging materials must be stamped with the required mark to confirm the treatment ..

Will the fumigation affect the quality of commodities or be harmful to people?

Fumigant affect insects as well as commodities in vapor form, after properly ventilated most of the vapors in the shipment are released back to the environment. Whether the quality or safety of the commodities is affected, depends entirely on the fumigation technique. The proper selection of fumigant, proper injection/placement of fumigant, and thorough ventilation will ensure that the quality of the commodities after fumigation is not affected. This can only be achieved with reputable fumigation units with full knowledge and practical experience.

What kind of packaging is suitable when commodities are fumigated?

Insects in commodities can only be destroyed when a sufficient concentration of vapor penetrated in for a necessary period. Common types of packaging such as Jute bags, and PP bags allow vapor to penetrate, so they are suitable for fumigation techniques. In contrast, types of packaging such as PE bags, 2-layer packaging with PE film, BOPP bags, laminate, etc. will prevent vapor from penetrating, so they are not suitable when fumigating commodities. When commodities are required to be packed with these types of packages, they must be punctured, opened, unsealed, or must be fumigated before packing.

How to load commodities in a container for the best fumigation results?

In principle, the loading of commodities must allow the vapor to diffuse evenly throughout the fumigated space so that the fumigant concentration can be evenly diffuse in all directions and be effective enough to thoroughly exterminate insects. Therefore, when loading commodities into the container, the volume of commodities must not occupy the entire volume of the container, the commodities at the bottom of the container should be placed on a pallet layer and the surface of the commodities should be at least 30 cm from the ceiling of the container so that the vapor can circulate evenly around the commodities.

What are the conditions required to conduct fumigation?
  • Commodities must be in normal condition in terms of storage or export standards (water content, temperature, etc.)
  • Must be able to seal the space that is to be fumigated (covered with canvas, completely sealed, etc.)
  • There must be enough time to incubate depending on the fumigant used.
  • Packaging is not airtight.
  • There must be space to ventilate the fumigant after the incubation time is finished.
The fumigation activities are under the management and supervision of which agency?

The Plant Protection Agency under the Ministry of Agriculture and Rural Development is a State management agency with the function of managing and supervising fumigation activities in the territory of Vietnam. When the commodities are exported, the National Plant Protection Agency of the host country must check the status of insects or pests on the commodities and make necessary decisions.

How long in advance do customers need to notify VFC when there is a need for fumigation?

VFC is always ready to serve customers 24/24. However, for the fumigation to be proactive and the technical requirements to be fully met, customers should notify VFC (by phone, email, Zalo) 24 hours before performing fumigation (for a container). When there is a request to fumigate large-scale warehouses or fumigate ships, customers need to notify VFC as soon as possible so that we can conduct a survey and give technical advice (if necessary) before the fumigation.

Besides the fumigation of preserved, import and export commodities, what other related services does VFC provide?

Currently, VFC provides a variety of services. Besides fumigation, VFC also provides pest control services (control of flies, mosquitoes, ants, cockroaches, rats... in hotels, restaurants, offices, and industrial zone...); sealing containers, and providing desiccant for exported containers. In addition, VFC also provides consultation and training on fumigation, integrated pest control (IPM), etc. VFC also supplies marine safety equipment (masks, toxic gas filters, toxic measuring devices, fire-fighting equipment, lifebuoy, etc.) depending on the customer's request.

The procedure for container fumigation.

Reasonable and simple are VFC's criteria to give customers the best service:

Customers send fumigation requests to VFC via phone, email at the office, or directly to the fumigation stations in the areas. For VFC to serve customers in the best way and ensure that your container is fumigated, please send a request via email or Zalo. The more information, the better.

  • VFC’s technical staffs at the fumigation stations (all ports and key areas) perform work as required or advise customers on related technical issues. The fumigation will be carried out in accordance with the National Technical Regulation on the technical process of fumigation, promulgated by the Ministry of Agriculture and Rural Development (QCVN 01-19: 2010/BNNPTNT).
  • The fumigation record signed by both parties will be sent to VFC's office.
  • The incubation time depends on the nature of the fumigant used. The minimum incubation time for Methyl Bromide is 24 hours and for Aluminium Phosphide is 120 hours.
  • VFC conducts ventilation when the incubation time is finished at the port, then process to retrieve AlP residues (if requested)
  • Based on the B/L sent by a customer, VFC will issue a fumigation certificate at the customer's request.

Note: The fumigation request form can be downloaded from our website: www.vfc.com.vn at the section Fumigation registration.

The procedure for storage fumigation
  • Customers send requests according to the form (via email, or phone).
  • VFC will discuss further if additional information is needed.
  • VFC's technical staff conducts field surveys and talks directly with customers.
  • Make an implementation plan; write an overall control program to send to customers and wait for confirmation (for large warehouses, factories, etc.), signing contract (if requested).
  • Fumigating the consignment, spray the outside of the consignment or the entire storage as requested.
  • Fumigating the consignment, spray the outside of the consignment or the entire storage as requested.
  • The incubation time depends on the nature of the fumigant used.

  • Ventilate the consignment, check and evaluate the result of the fumigation.

  • VFC issues a fumigation certificates at customer request.
Can a fumigated consignment be re-infected with insects?

Yes, it can happen if there are no protective measures. We all know that fumigants have the effect of exterminating harmful organisms present in commodities. A consignment that is thoroughly fumigated (exterminate all pests thoroughly)will be isolated and protected from outside infection, only then as a result, there will be no fear of insects. However, in reality, we are not always in control of everything. Therefore, a full understanding of the possible causes of re-infection and remedial measures is of great interest to both the consignment owner and the fumigation company.

Are there other methods to exterminate insects aside from fumigation?

Yes, there is. There are some other methods such as controlling the air (based on the principle of low oxygen content, combined with CO2), hot and cold treatment, irradiation, etc. However, in reality, implementing these methods requires very complicated techniques, high costs, and having to move commodities to specialized processing areas, so the feasibility is still low at present.

Some export contracts require the use of Phostoxin, while others require the use of Phosphine (PH3) and some contracts stipulate the use of Aluminum Phosphide as a fumigant. So what's the difference between these contracts? Which one is more accurate?

Fumigants

Phosphine (PH3) is a toxic gas used to exterminate insects, released from a chemical reaction:

AlP (Aluminium Phosphide) + 3H2O (Humidity) = PH3 (Phosphine) + Al(OH)3

Phostoxin, Gastoxin, Quick Phos, Celphos, etc. are names of products made by different manufacturers with the main active ingredient being Aluminum Phosphide 56%. Normally, when fumigating, every 3g of AlP will produce 1g of PH3 if there is enough incubation time for the chemical reaction to occur completely. Depending on what is written in the contract or L/C, the fumigation company will prepare a file and issue a certificate accordingly. Therefore, when the deed shows that the fumigant is Aluminum Phosphide (9 g/m³) or Phosphine (3 g/m³), it is reasonable as long as it is consistent with the L/C or the contract.

Why use desiccant in containers when exporting commodities?

There is always a certain amount of water vapor in the air, about 30 g of water vapor in 1 m³ of air when the temperature is 30 - 32°C and the relative humidity is 80%. When the container is sealed, the gas exchange process is limited, causing the temperature to rise, possibly to 50-60°C, then the amount of water vapor in the air also increases, possibly up to 100 g/m³ of air. The outside temperature is usually lower than in the container, so the steam that rises to meet the metal ceiling will condense and fall on the surface of the cargo, causing wet conditions and mold growth. The purpose of using desiccant is to maintain the humidity of the air in the container at a safe level, prevent the above condensation from occurring and thereby protect the commodities from moisture or harmful mold.

In addition to the amount of water vapor present in the air, what other sources can lead to the above-mentioned vapor condensation effects that require the use of a desiccant?

The amount of water vapor that causes the above condensation, comes from the container floor because most of the container floors are made of wood with fairly high moisture (from 25-30%) and about 5% of that amount of water will participate in the evaporation and condensation of water vapor on the surface of the commodities. Therefore, if the container is not used with a desiccant, it is easy to have the possibility of mold and damage to the commodities, especially with high-value commodities, the damage is great. Currently, VFC provides the service of using PVC bags to protect all commodities inside the container – please contact VFC for further advice.

Besides fumigation, does VFC provides consultation as well as integrated pest control programs to improve economic efficiency for customers?

VFC is Vietnam first fumigation company with over 45 years of experience and has close cooperation with many international specialized organizations ready to provide free consultation on all issues related to pest control work in general and fumigation in particular, building the Integrated Stored Pest Management program, conducting many training courses, on-site consulting for customers' relevant personnel to bring the highest efficiency to customers in the preservation and export of commodities.

Some customers and contracts requested fumigation using the J System (Low Air Flow Fumigation Method). So what is the difference between fumigation using the J System and without the J System?

Request for fumigation using the J System is often applied when fumigating with Aluminum Phosphide. Because Aluminum Phosphide reacts with water vapor and releases Phosphine, which is a relatively light gas (the density is 1.17 compared to air), difficult to diffuse deep into the cargo layer at the bottom of the hold, especially with cargo holds of large capacity. To ensure uniformity of chemical concentration at all areas in the hold as well as to increase the efficiency of the fumigant, many customers have requested the use of The J System - Low airflow fumigation method. Currently, VFC is the only company in Vietnam applying this copyright fumigation method. The operating principle of this system is detailed in the Technical Information section – J System – Advanced fumigation method. -> J System is also applied to other fumigation such as fumigating commodities stored in silos, bins, warehouses, etc.

Is In-transit fumigation the same as Quick fumigation?

They are not the same. Some customers interpret "In-transit Fumigation" as "Quick Fumigation" – This is incorrect. Starting from the need to save unnecessary waiting time for ships, International Maritime Organization (IMO) has issued regulations for In-transit Fumigation. This can be found in the "Recommendations on the Safe Use Of Pesticides in Ship". The fumigation of the In-transit ship is carried out when all the specified conditions are followed.

After placing the medicine in the cargo hold, and checking the safety of the areas as prescribed, the fumigation officer will instruct and hand over the next tasks in the process to the ship captain such as the time needed to incubate the fumigant according to the nature of the fumigant used, ensure safety, cargo must be ventilated, prevent infection, etc. After that, the ship can depart. Thus, in practice, there is no concept of Quick fumigation, but only In-transit Fumigation.

Can a properly fumigated consignment be re-infested with insects at the destination port?

It is quite possible if the consignment protection measures are not taken into account and fully implemented. Fumigant is only effective against insects presented on the cargo at the time of fumigation. After the incubation period, the consignment is ventilated so that the commodities return to normal condition. This issue is covered in detail in the "Technical Information section – Why are insects still alive at the destination port?"