Evaluation of Wireless Phosphine Sensors for Monitoring Fumigation Gas in Wheat Stored in Farm Bins

Abstract

Fumigation of grain bins with phosphine tablets is one method of insect control for stored products. Monitoring the concentration of the toxic gas at many locations over several days for a given structure or container can be challenging. In this study, a commercially-available system that wirelessly measures phosphine was evaluated in small-scale and large-scale tests. Small-scale testing was performed to study the repeatability and accuracy of the sensors. The wireless sensors were within 30 ppm of each other, over a range of 700 ppm phosphine. Large-scale testing evaluated the system during the fumigation of wheat stored in 7 m diameter, 120 metric ton, steel grain bins. As a reference, monitoring lines were distributed at several positions and depths in the bin in order to sample phosphine gas concentrations. A series of three fumigation trials were performed, with each lasting for over six days. The wireless devices collected local phosphine concentrations and temperatures every two hours without assistance from personnel. Although the fumigation trials were significantly different in terms of patterns in gas concentration over time, the two sampling methods gave similar trendlines. However, the automated data provided a more detailed picture of the fumigation process. This information may help fumigation managers to better evaluate fumigations and assure successful insect control.

Delayed mortality, resistance and the sweet spot, as the good, the bad and the ugly in phosphine use

“…However, there are cases where phosphine is used for short intervals, as in the case of quarantine and pre-shipment treatments (QPS), in different export scenarios of fruits and vegetables 56,57 . Nevertheless, even in phosphine fumigations that are carried out in large structures, such as silos with grain bulks, the concentration of the gas changes dramatically over time, resulting in large areas to be partially treated, or even untreated [58][59][60] . In a recent study, Agrafioti et al 60 demonstrated that phosphine distribution within silos is rather uneven, and may leave large areas within the grain Table 5.…”

Development of detection methods for the diagnosis and analysis of highly toxic metal phosphides: A comprehensive and critical review

“…Brabec et al 111 designed a wireless gas sensor system for automated detection of PH 3 in order to monitors fumigation treatments, which presents additional information about PH 3 concentration changes during treatments in different areas of grains containers resulted from different events such as effects of weather changes or recirculation fan. According to Figure 3(E), this system included two bines, filled of wheat, and two wireless sensors of PH 3 that were placed at center and wall positions each bine.…”

“…117 So the study of Brabec et al, 111 which applied the wireless gas sensors for automatically evaluation of spaces of grain bines is valuable. As mentioned for study of Brabec et al, 111 the wireless gas sensors were mounted at center and wall locations. As a defect that can be mentioned, the rate of PH 3 release at different regions is different leading to differentiating the saturation rate of wire-less gas sensors at different location.…”

“…“Reprinted from Sensors and Actuators B, Vol 21, Nakano and Ogowa, Preparation of thin gold‐film electrode for an electrochemical gas sensor for phosphine and arsine, Pages 51–55, Copyright 1994, with permission from Elsevier” 1 ; (E) mounting the wireless and hand‐held meter gas sensors in grain bines: (a) design of grain bins, (b) wireless, and (c) hand‐held meter gas sensors. “Reprinted from insects, Vol 10, Page 121, Figure 1, Figure 2, Figure 3, https://www.mdpi.com/2075-4450/10/5/121, Copyright 2019, published and licensed by MDPI, according to the license terms of Creative Commons are available at https://creativecommons.org/licenses/by/4.0/” 111 …”

“…This manual sampling and measurement is time consuming, difficult to inset the monitoring lines into various locations, and highly required to trained persons to check at regular time intervals 117 . So the study of Brabec et al., 111 which applied the wireless gas sensors for automatically evaluation of spaces of grain bines is valuable. As mentioned for study of Brabec et al., 111 the wireless gas sensors were mounted at center and wall locations.…”