Non-Fumigation Pest Control
Phosphine fumigation remains the de rigueur pest control option in the tobacco industry. But, there certainly are other alternatives available. Tobacco Asia investigates this with German outfit ThermoNox GmbH.
By Thomas Schmid
Phosphine fumigation is most commonly employed when tobacco beetle (lat. Lasioderma serricorne) or tobacco moth (lat. Ephestia elutella) are wreaking havoc in tobacco warehouses or infest production floors and machinery.
The method requires considerable preparation effort, as areas to be treated must be hermetically sealed. The highly toxic gases also make these areas inaccessible to humans for a couple of days, resulting in potentially long production downtimes. Furthermore, additional time is required for post-treatment aeration.
But, there are options that avoid this inconvenient procedure. One would be thermal treatment, which uses high heat of at least 80 degrees Celsius to kill off the invading insects – but alas with the risk of damaging manufacturing equipment or raw materials in the process. Further alternatives are low-oxygen or chemical net treatments (see our side boxes), but they impart some limitations as per where and when they can be used.
Originally developed for grain mill pest control
A quite gentle alternative is the low-heat treatment offered by ThermoNox GmbH. The patented and trademarked disinfestation system uses strategically placed electrical ovens supported by special fans, according to company owner and general manager, Martin Hofmeir. Originally developed between 1993 and 1994 as a pest control solution against flour and rice beetles in the Hofmeir-owned grain mill, a few years later the system made inroads with bakeries and other food processing factories.
The system was subsequently also picked up by the hospitality sector, as it turned out that ThermoNox also could get rid of bed bugs and other nasty critters lurking in hotel rooms or restaurants.
”Beginning in 2000, we landed our first bed bug disinfestation contracts from hotels. In the meantime, the hospitality industry has become our second-largest customer after the food-manufacturing sector,” Hofmeir recalls.
The tobacco industry follows in third place, but only because “there are marginally fewer companies around than in the other industry sectors.”
Word spread by itself, aided by CORESTA
The company had actually never actively promoted its pest control product to the tobacco industry at all.
“In fact, we were approached by our very first tobacco customer for help with an infestation problem… and I have no idea how they even found us,” Hofmeir said.
That first customer was BAT, or rather a BAT-owned tobacco factory in the southern German city of Bayreuth, where disinfestation with the ThermoNox solution proved successful. Austria’s national tobacco company soon became the company’s next big client. Franz Rappl, at that time Austria Tabak’s executive in charge of pest control, subsequently filed a detailed report about the extermination with CORESTA. This led to further disinfestations at large tobacco firms, among them JTI and PMI.
Hauni gets on board
Apparently reacting on the CORESTA report, in 2007 leading tobacco machinery manufacturer Hauni invited ThermoNox to Hamburg to lead a test disinfestation project on its wide range of equipment. Highly satisfied with the outcome, the machinery company officially endorsed ThermoNox as a “suitable pest extermination method for all Hauni machines”, as Hofmeir puts it.
“To the best of our knowledge, no other pest control process has achieved that status [with Hauni] so far.” That endorsement alerted even more tobacco industry customers to the then still relatively obscure ThermoNox method. Two decades after the solution’s inception, Hofmeir claims that his company has “successfully conducted tobacco industry disinfestations with ThermoNox in about 15 countries worldwide.”
Global representation through partnerships
This is of course not all directed from ThermoNox’s home base in the small Bavarian town of Fahlenbach. Instead, the company has since entered into various partnerships with local distributors and service companies around the globe, all of whom “are licensed to conduct disinfestations with our method,” according to Hofmeir.
”We are [today] represented in all regions, particularly well in western and eastern Europe but also through joint ventures in countries like Mexico, Japan and Australia, Hofmeir elaborates. He adds that “about 17 years ago we partnered with SAN-EI in Fukuoka, a Japanese company that handles the [entire] Asian market for us.”
ThermoNox systems have been sold to and are currently in use in several Asian countries. “Only a short while ago, we realized two projects in the Philippines, for example,” Hofmeir recounts.
Easy-as-pie operation and maintenance
Unlike phosphine fumigation, which requires licensed personnel to carry out the hazardous procedure, the Thermonox method can be handled by anyone with a modicum of proper training, including a factory’s own technical staff.
“If done internally, the respective company can always receive guidance from us via email or telephone consulting,” Hofmeir says. However, he only recommends this when smaller areas – like single rooms – need to be treated. In case of an entire factory floor, he prefers to dispatch Thermonox technicians to ensure that the equipment is set up properly and the heat-dispensing ovens are distributed correctly.
Nonetheless, regular system maintenance and working condition check-ups can easily be accomplished by any in-house technician.
“Our equipment has very few wear and tear parts,” Hofmeir reasons, adding with visible pride: “Not a single one of our ThermoNox machines has ever failed and all systems that we have dispatched over the decades are still in active use.”
Careful set-up to ensure total efficacy
ThermoNox is principally effective against all development stages of tobacco beetle and tobacco moth, i.e. eggs, larvae, and adult insects. The reason for that is the high air temperature susceptibility inherent to practically all insect species.
“Insects cannot sweat to regulate their core temperature, but instead adjust to the surrounding air temperature,” elaborates Hofmeir. Once that air temperature reaches 50 degrees Celsius and above, their body protein begins to congeal, basically killing them. With a typical treatment cycle lasting 24 to 48 hours, ThermoNox uses sustained low heat that is circulated with the help of fans and ducts. For treatment efficacy, it is crucial that individual ovens (as well as accessory equipment like floor fans) are positioned correctly. “The produced heat must be distributed in a certain manner to be lethal to the insects.”
Limitations to an otherwise excellent solution
But there is one important limitation to the ThermoNox method’s otherwise excellent insect eradication efficacy.
“Tobacco bales are impossible to be treated. The tightly packed leaves act like an insulator and the applied heat will not penetrate deep enough to actually reach beetles, their eggs, or larvae,” Hofmeir admits. Yet when used on vast factory floors, the ThermoNox process brings along a rather beneficial side effect. The equipment’s warming-up phase at 35 to 44 degrees Celsius simulates summer temperatures to the insects; in other words: mating season. This causes them to leave their hideouts, allowing the exterminator to identify where the biggest infestation has amassed so appropriate action can be taken – such as concentrating the ThermoNox in that particular area.
Netting tobacco pests
Non-fumigation pest control options are far and between. One ingenious solution is BASF’s Carifend system. Specifically designed to protect warehouse-stored tobacco, it is the only insect control system that provides continuous, preventative protection without having to resort to conventional phosphine fumigation. Carifend also is the world’s first insecticidal net technology application and can help reduce merchandise exposure to fumigants. According to BASF, the specially developed net, impregnated with an insecticide, has been proven to be up to 100% effective in controlling stored tobacco pests. BASF provides an individual, turn-key service for Carifend, including design, manufacture, installation, system monitoring, and disposal. The method, however, is not suitable to disinfest tobacco machinery.
(Source: BASF website)
When pests cannot breathe
As simple as it sounds, depriving tobacco pests of oxygen literally lets them choke to death. Several suppliers offer this interesting alternative to phosphine fumigation. Known as low-ox or nitrogen treatment, the procedure is straight forward: Infested tobacco is isolated in a special treatment chamber (or, alternatively, under an air-tight plastic foil tent) and the oxygen is replaced with nitrogen for a prescribed time period, causing the insects to die, including their larvae and eggs.
The method is preferably used either pre- or post-shipping, but can also be deployed on tobacco batches in the warehouse. The downside is that investment cost may be considerable if a fixed treatment chamber built on location is wanted. And with temporary plastic sheeting tents in warehouses, the process can turn out to be quite laborious as the structures must be assembled and disassembled repeatedly to treat a large amount of tobacco in batches. Furthermore, single treatment periods can be lengthy and last up to 48 hours. However, the nature of the method practically guarantees an extermination rate of 100% -- and it is of course entirely non-hazardous both for humans and the environment.