South Africa - Infested Wheat Cargoes from U.S.

November 2007

PDF Version


 “Bugged” Out

There appears to be a growing problem with wheat arriving in South Africa from the United States where the cargo has been infested with “Rust Red Grain Beetles”. 

All the vessels concerned are being checked and passed fit for loading by the National Cargo Bureau (NCB) and the United States Department of Agriculture (USDA). These authorities have all issued certificates stating that the holds were found to be clean, dry, free of insect infestation and suitable to store or carry the grain cargo. On completion of loading, the cargoes are being fumigated with Aluminum Phosphide tablets. Whilst Aluminium Phosphide is an effective fumigant, it is only effective provided the application method being utilized is correct. 

The dosages stated on the certificates issued by the fumigators at load port indicate that 33 grams of fumigant per 1000 cubic feet of hold space is being used and the fumigators are issuing certificates declaring that the fumigant was applied using the “trench” method.  

We have noted from our attendance on board all of the vessels that the fumigant tablets appear to be simply scattered across the top of the stow in each hold. This application method is clearly ineffective since on arrival in South Africa, the cargoes are infested with “bugs” and the local authorities and receivers are simply rejecting the cargoes until they have been re-fumigated. The re-fumigation takes place on board the vessel at great expense to all parties concerned. The costs increase very quickly since the crew have to be placed ashore in hotels, emergency services put on standby and extra security provided to the vessel. 

The vessels are being re-fumigated at Durban with Methyl Bromide Gas for a period of 36 - 48 hours using what is referred to as the “J” system of fumigation. This method entails using pipes, which are inserted into the cargo that go directly down to the tank top. This method then enables the gas to be circulated throughout the cargo thus eliminating all the “bugs”.  

Another method often used to fumigate cargoes is known as the “probing” method. This involves pushing metal probes deep into the stow, to a depth of approximately 2 – 3 metres. Phostoxin pellets are dropped down the probe and then the probe is removed leaving the pellets in the cargo. Whilst this is certainly a cheaper method of carrying out the fumigation, it does not have the same effectiveness as the “J” system, because the fumigant is not circulated throughout the cargo; it will only penetrate to the depth that the probe is able to achieve which is usually about 3 metres. 

A further method involves putting the tablets into the cargo at various stages of the loading in order to disperse the tablets evenly throughout the hold and thereby fumigating the entire cargo. This, in theory, is a good and inexpensive option. However, if due to operational circumstances, the loading is stopped for a period of time, the tablets will start to release their gas, creating a potentially lethal atmosphere in which to work. In reality, this is not really a viable option.  

The usual method of fumigating is the sprinkling of tablets over the surface of the cargo whilst in stow. This fumigation method is, in the view of the writer, ineffective when it comes to wheat. In stow, wheat has a high density and it is suggested that it is this factor, which prevents the gas emitted by the tablets from being able to penetrate the cargo down to the tank top.  

While the fumigation certificates issued to vessels at the various load ports show that the correct amount of fumigant has been used, the results appear to reflect a very high concentration of fumigant at the top of the stow, but weaker levels deeper down into the stow. It would also appear that Aluminum Phosphide, as a fumigant, is really only effective for about 8-10 days after which, any bugs or eggs that are present in the lower reaches of the stow and which have not been eliminated are able to move through the cargo. 

The writer would recommend that the P&I correspondents in the USA be advised of the problem and provide necessary assistance on how to beat the “bugs” and save on costs subsequently arising in South Africa. 

With thanks to Michael Heads of P&I Associates (Pty) Ltd, Durban, for preparing this article.