Proper procedure

| January 1, 2018

Tobacco pest control technologies would be more effective if they were carried out correctly.

By George Gay

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As I started to research this story about the control of insect pests in tobacco, a subject that I previously covered in 2011, I was hit by a feeling of deja vu. The value of the tobacco currently lost each year to tobacco beetles and moths is thought to be roughly—probably very roughly—$800 million, the same figure as was being bandied about in 2011. Also, the problem highlighted in 2011 of the emergence of increasing numbers of insects resistant to the most commonly used fumigation technique has not been solved. In fact, it has become worse, implying, I suppose, that the value of the tobacco lost must have increased or must be increasing. And the reason for the increase in insects that are resistant to phosphine gas fumigation is, as it was in 2011, down to incomplete and/or faulty fumigations.

Now, as then, experts involved in such techniques will tell you that phosphine is a good gas for the job and, if used properly, will kill all insects, even resistant ones when the more demanding Coresta guidelines for fumigating such insects are followed. And they will tell you that phosphine fumigation must remain one of the weapons in the tobacco industry’s pest control armory. But they will tell you too that phosphine fumigation is often not done properly, because the environment is unsuitable, the equipment is deficient, there is a lack of time (fumigation in the case of resistant insects can take up to 12 days), there is a lack of understanding of what should be done by those undertaking the task, and, something that might impinge on any one of the aforementioned, there has been a failure to pay a reasonable price for the job where, as is often the case, it is carried out by third parties.

Oxygen starved

Given all this, the bad news is that, unlike in 2011, there seem to be no new systems coming to the rescue. In 2011, controlled-atmosphere (CA) systems, which had been used in respect of other commodities and various products for 15 years or more, were starting to gain traction with tobacco people—those involved in warehousing, shipping, trading and manufacturing tobacco. Indeed, in 2012, Coresta issued a guideline for the treatment of tobacco beetles with CA, a guideline that was revised to include the tobacco moth the following year.

Used properly, CA offers enormous benefits because it kills all tobacco beetles and moths in all their life cycle stages. It can be used for all types and varieties of leaf tobacco without affecting taste and color, and it can be used for tobacco products.

And because of these benefits, CA is being adopted, and the rate of its adoption is likely to increase in the future, if for no other reason than that the industry cannot afford to continue losing the fight against resistant insects, especially in an era when it is likely that increasing numbers of pesticides will be banned and removed from the market. Rene Luyten of b-Cat, which, among other things, supplies CA systems, told me at the end of November 2017 that business was good—that his company was expanding. Just in the previous two months, he said, his technicians had installed CA chambers in Germany and Poland, and they were preparing to install some in Jordan.

But even so, as can be inferred from the fact that even now CA is being used to treat only a small proportion of tobacco (I was told variously “from 1 percent to 2 percent” to “certainly not more than 10 percent”), this system has its drawbacks. Probably the major hurdle to having more tobacco treated with CA is the cost of the investment involved, a factor that is being brought into sharper focus by the day as talk of combustible cigarette endgames becomes more serious.

CA involves the construction, usually within a warehouse, of a gas-tight chamber or chambers in which the temperature can be controlled and the composition of the air can be changed to deprive the insects of oxygen. In this way, given the correct period of exposure to this controlled atmosphere, all stages of the beetle are killed—the adults and larvae, which are relatively easy to deal with, and the eggs and pupae, which normally present more of a challenge.

As is obvious, I think, investment decisions about such installations might be easy to make when they are being taken ultimately by companies with deep pockets and refer to places where power supply is not a problem. For one thing, CA is probably a better fit than is phosphine fumigation with such companies’ sustainability strategies. But they can be difficult decisions for smaller operators even though it is a moot point whether CA treatment is more or less expensive than is phosphine fumigation. I was told by different people that CA was more and less costly than is phosphine fumigation, and this disagreement is not surprising given that CA is relatively new, making it difficult to calculate how much tobacco is being saved. Also, different companies will take different views on depreciation.

And there are other important factors, too. In some tobacco production areas, export logistics might determine that tobacco departure points must be changed, while the location of CA chambers are fixed. In some growing areas, such as southern Brazil, the sheer scale of production might be a deterrent, and in others, having to put tobacco through chambers, necessarily in fixed locations, can act as a constriction in the logistics flow.

And following on from this idea, one thing that works against a decision to install CA chambers is that the use of phosphine fumigation is very flexible. The fumigator can, within reason, choose where the fumigation should be done and, providing it is done properly, he will achieve his aims.

Improving treatments

So up to a point the important question comes down to whether the two processes are likely to be carried out properly. And here, for the time being at least, CA seems to win hands down. For one thing, CA tends to reduce greatly the possibility of human error in the process. Once the tobacco has been positioned in a chamber and the equipment and monitoring devices have been programmed, technology takes over. The programmed atmospheric conditions are achieved, and they can be maintained via a system of strategically positioned monitors feeding back instructions to the various controls.

So far, however, such sophistication has been largely lacking when it comes to phosphine fumigation. Monitoring seems to be, in most cases, sketchy, and feedback controls nonexistent.

It is possibly counterintuitive, but the worst criticism seems to be leveled at phosphine fumigations carried out in shipping containers. I was told by one bemused observer that the tobacco industry continued to accept the fact that it was spending money fumigating in containers when it was known that such operations were not being carried out properly and were creating more insect resistance. Fumigations, on the other hand, carried out under tarpaulins are relatively successful, given that the tarpaulin is of the right type and in good condition.

Shipping containers, even with their vents taped up, tend to leak gas at unpredictable rates, but the main problem is that the fumigator often has little idea what has gone on. I was told that to monitor a container would require instruments to be positioned at the back of the container, in the middle and at the door. But this was rarely done because it was too expensive. Instead, monitoring was usually done only at the door, where the phosphine plates were placed and where the levels of the gas would be the highest. In addition, the monitoring would be done only once a day.

But things might be about to change. Nico Vroom, one of the earliest advocates of CA systems, told me at the end of November 2017 that he was shortly going to an exhibition in Dubai, United Arab Emirates, where he would be demonstrating Centaur’s wireless fumigation sensors, with which it would be possible to monitor phosphine treatments 24/7 via a cloud platform rather than once a day. Previously with Eco2, Vroom was at the time he spoke with Tobacco Reporter in the process of setting up a pest control consultancy—N.I.C.O. (No Infestation Consulting Organization)—through which, in part, he will be assisting companies with CA installations and operations and helping to improve phosphine treatments.

It was probably misleading to say above that there were no new systems coming to the rescue. It is true, but there are new techniques being trialed and used in various parts of the world. For instance, CA chambers, which have been installed in Mozambique without the equipment necessary for CA treatments, are being used for phosphine fumigation. Such chambers provide an environment in which phosphine fumigation can be properly monitored and controlled. They offer the advantage that without the CA equipment they are less expensive than they otherwise would be, while providing the opportunity to install such equipment later. Also, trials have been conducted using shipping containers as chambers for CA treatments.

And work has been carried out on creating insect-free warehouses—warehouses that prevent free-roaming insects from entering and that therefore remain insect-free providing all of the tobacco introduced into them has been properly treated.

Guy Harvey, the CEO of Transcom Sharaf in Africa (South Africa, Mozambique, Malawi and Zimbabwe), said that his company, which is in the process of building an additional 18,000 square meters of warehouse at the port of Beira, Mozambique, was trying a lot of different techniques to reduce beetle counts and increase hygiene levels. In part, it was working with the port authorities, describing to them the losses that insects could cause and encouraging them to enforce strict hygiene levels throughout the port.

Such hygiene is vital during storage, transport, processing and manufacturing because whereas the tobacco beetle and the tobacco moth are public enemies No. 1 and No. 2, they are not exclusive to tobacco. This was a point made by Steven Bailey, group managing director of Barrett and Co., which supplies the MoBe Combo Mk2 pheromone-based monitoring trap for the detection of beetles and moths. In fact, Bailey emphasized this point by always referring to these insects by their Latin names: Lasioderma serricorne, the beetle, which is also found, for instance, in cocoa, and Ephestia elutella, the moth, which is commonly known as the warehouse moth and can be found in stored food such as grains.

The MoBe trap is unique in that it attracts both the beetle and the moth, and Bailey said this was important. Whereas the beetle was often considered to be the priority pest, probably correctly, the moth should not be underestimated. At one time, the moth was seen mainly as an insect of northern Europe, but now, because of climate-controlled warehousing and shipping, the moth, in pupae or egg form, was able to migrate. This meant that both beetles and moths could thrive just about anywhere in the world and meant that, in one sense at least, they were both equally problematic.

Such traps can act as an early warning system and can help pinpoint infestations so that fumigations can be limited. And while it is not really a significant factor in their use, by their very nature they do trap and kill a limited number of insects.

But Bailey pointed out that it was important that traps went wherever tobacco went: into warehouses, shipping containers, trucks, processing plants and manufacturing factories. And this was a point echoed in one way or another by everybody I talked with. Ridding tobacco of insects by fumigation, CA treatment or freezing comes to naught if the tobacco is not properly monitored and handled after such processes.

There’s that “properly” word again. Tobacco must be properly monitored and properly handled, including by ensuring that traps are used properly. A trap that is left beyond its end date will not be giving off the plume of pheromone necessary to attract beetles and moths, and it could in this case provide a false sense of security.

Category: Also in TR, Editorial Archives

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