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40 TOBACCO INTERNATIONAL JANUARY/FEBRUARY 2016 maintain the effectiveness of phosphine, it must be used correctly. "Formal research and data based on historical experiences are constantly evaluated to ensure the safety and effec- tiveness of phosphine," Yeaman said. "We put a great deal of effort into training end users to ensure safe, effec- tive fumigations. This is done by em- phasizing the proper way to transport, store and apply our products. And ef- fectively applying them and employing proper sealing and dosing and monitor- ing methods to offset the increased pres- ence of insects less susceptible to phos- phine. R&D of new technologies, deliv- ery methods and product improvements is an on-going process. In addition to internal advances, we are a longtime member and active participant in the Pest Sanitation and Management sub- group within CORESTA (Cooperation Centre for Scientific Research Relative to Tobacco). This sub-group collaborates on the development of the most effec- tive control measures, resulting in in- creased insect mortality and more suc- cessful and economical treatments." Y e a m a n a l s o e x p l a i n e d t h a t Phostoxin® and Magtoxin® are wide- ly marketed and considered safe when applied responsibly. It is interesting to note that no traces of pesticides or their active agents are left on the tobac- co after application. "Aluminum phos- phide and magnesium phosphide never come into contact with the tobacco," Yeaman said. "Both products generate phosphine gas which is the insect con- trol agent. The phosphine gas leaves virtually no residue and does not ad- versely affect the tobacco. The fumi- gants are very safe when handled prop- erly, per label instructions and respected as a Restricted Use Pesticide," Yeaman said. "Phostoxin was invented in 1951 and US registration was granted on November 10, 1958. Magtoxin,® Fumi- Cel® and Fumi-Strip® were registered in the United States on June 6, 1979. For decades, the Magtoxin® product line has been the gold standard in high qual- ity tobacco fumigation processes." We asked Yeaman to give us an insight to the relative effectiveness of aluminum phosphide and magne- sium phosphide and how such factors as ambient temperature affect each product and what the ideal application circumstances are for either product, Phostoxin® or Magtoxin.® "When used properly, phosphine is very effective against all life stages of many pests," Yeaman said. "In addition to temperature, moisture or humidity is also necessary as a catalyst for the re- action and creation of phosphine gas. Magtoxin® is effective at producing phos- phine gas at lower temperature and hu- midity levels than Phostoxin.® All factors being equal, Magtoxin® does react faster. Yeaman added that weather, hu- midity and temperature can affect or influence pests and their ability to in- fest and damage tobacco. "Insects thrive within a narrow range of envi- ronmental factors so treatments should be made then," Yeaman said. "Yes, we adjust dosage rates and exposure periods based on the commodity temperature. If these environmental factors are not met, we strongly discourage the fumiga- tion treatment of cigarette beetles. Just like the best time for fumigation is when the environmental conditions are ideal, it's usually true that infestation levels, if monitored correctly, will fall within those periods. The treatment tobacco re- ceives in the field has little or no effect on our process of post-harvest and mostly processed products. Fumigation should occur when infestation levels increase beyond the individual customer's set threshold levels. Additionally, processed tobacco often gets exported, and these shipments must be made in accordance with USDA Phytosanitary requirements. "Most companies schedule an an- nual fumigation," Yeaman said. "Insect activity is monitored and once this ac- tivity reaches an actionable level, fumi- gation is scheduled. As the fumigation process does not leave any residual in- sect control, care must be given not to re-infest the treated space and tobacco within it." Product stewardship is stressed by Degesch America through the safe and effective application of its fumigants. DEGESCH AMERICA