Miller Magazine Issue 109 / January 2019

81 ARTICLE MILLER / JANUARY 2019 Recirculation is mandatory for all grain masses larger than 100 metric tons. The ideal recirculation should last during all the treatment as long as it does not increase gas leakage. When the recirculation is stopped, the result is loss of equilib- rium as shown in photo 4. Measuring Remote monitoring is changing the fumigation world. Pre- cision fumigation is not cheap to achieve and in most cases monitoring is made only at the beginning and at the end of a fumigation. Fumigators hesitate to send operators to take readings every day in a faraway silo. Wireless sensors offer new capabilities with continuous information upload. They allow the observation of each treatment in real time, al- lowing corrective actions and evaluation of each application. The cognitive software offers treatment prediction and gives recommendation to users based on numerous monitored pa- rameters. In the next years all fumigations will be monitored online. Inspect At the end of each fumigation, a thorough ins- pection must be made in search for surviving in- sects. Such a fin- ding will indicate a gap in the pro- cess and should lead to corrective and preventive actions. There are several aspe- cts in a fumigati- on that may lead to a failure like leakage, low dosage, low humidity, low temperature, wrong readings, short duration etc. By finding alive insects we rea- lize a failure. If we don’t find alive insects are we sure that the fumi- gation was successful? Probably not. Adult insects are about 15% of the total insect population (data on Tribolium), me- aning that we search for alive adults while the 85% of the population (larvae, pupae and eggs) may also be alive and almost impossible to detect. When a treated volume shows infestation a month or two later, it is a clear indication that the fumigation failed. Frequency of applications Depending on the label of phosphine and the country le- gislation, a second phosphine fumigation on the same lot, in the same year, may not be allowed. Here is another serious reason for improving the art of fumigation. Are non-chemical fumigation methods successful in silos? Several silo treatments like: oxygen, controlled atmosphere, CO2, N2 are considered very successful and are ava- ilable in many places around the world. Academic research has been conducted by several institutes leading to the conc- lusion that non-chemical methods can be equally successful. Precision monitoring is the key to success. People safety The right approach starts with a Risk Assessment for each treatment. This can be part of the Fu- migation Plan as described on the first paragraph. Personal monitors, real-time monitoring, visual and sound alarms shall be involved in every fumigation. Life is very valuable to put it at risk and modern technology gives us many tools to use. There is no excuse for risking lives. It’s all about precision The fumigator must evolve. The art of modern fumigation is not in using traditional secret methods. The art is acquiring information and using it to succeed. Insects evolve, we should too. Sources 1. Presentation to IMFO group, Prof. C. Athanassiou, 2017 2. Fumigation Plan, Pestcon Systems Inc., 2016 3. Fumigating with Phosphine, GRDC Australia, 2013 4. Phosphine Fumigation Parameters, Coresta Guide No2, 2013 5. Fumigation Handbook, USDA, 2016 6. Pressure testing sealable silos, GRDC, 2014 7. Centaur sensors and platform, centaur.ag , 2019 Photo 4: stopping the j-system during the treatment leaves the phosphine gas to be moved by natu- ral convection currents, creating loss of equilibrium and serious fluctuation. Photo 6: modelling a silo fumigation using computational fluid dynamics Photo 5: a silo equipped with wireless sensors for monitoring fumigation and grain spoilage