Utilizing low oxygen to mitigate resistance of stored product insects to phosphine

Abstract

BACKGROUND Data are provided on the utilization of modified atmospheres, at a commercial scale, against stored product insect populations that are resistant to phosphine. The method is evaluated on different populations of two major stored‐product beetle species, Rhyzopertha dominica and Oryzaephilus surinamensis. The trials were carried out in commercial facilities, in which nitrogen was introduced through an embedded nitrogen generator. Each chamber contained three or four pallets of either currants or herbs. A computational model was developed to evaluate the nitrogen concentration. RESULTS In most trials, 100% mortality was recorded for both beetle species and all populations, regardless of the temperature and exposure intervals tested. Control progeny production ranged between 20 and 45 adults per vial for R. dominica, and 29 and 27 adults per vial for O. surinamensis. Simulation results reveal that nitrogen can easily penetrate the currants, and its concentration is uniform (differences are below 1.5%) across the pallet. Additionally, the simulation model revealed that lower temperatures do not have an impact on the nitrogen concentration profiles. CONCLUSIONS The modified atmosphere applications evaluated here were proved to be effective for all populations, regardless of the level of resistance to phosphine, and any survival could be attributed to the short exposure intervals. Modified atmosphere applications can be effective at a considerably short exposure interval, even at 2.5 days, which is an incontestable advantage for the use of this method against insects, at exposures comparable with those of commercial fumigations. © 2022 Society of Chemical Industry.

Effect of Nitrogen on Stored-Product Insect Control at Industrial Scale

“…Moreover, nitrogen killed almost all insects that had been placed inside the commodity, indicating that the replacement of air by nitrogen is progressing in a uniform way in the entire mass of the treated commodity. This observation is in agreement with the data that are reported by Agrafioti et al [ 19 ] for the distribution of oxygen within similar chambers, underlying that this distribution is not affected much by the prevailing temperatures. The findings of the present study are particularly important in the case of flour, where airflow is much more limited as compared with bulked grains that have large interstitial air zones among kernels.…”

“…The findings of the present study are particularly important in the case of flour, where airflow is much more limited as compared with bulked grains that have large interstitial air zones among kernels. Similar results for different exposure intervals have been illustrated by other researchers, as well as with different experimental protocols [ 11 , 13 , 15 , 16 , 17 , 19 , 22 , 23 , 24 ]. These results underline the merit of experimentation at the industrial/commercial scale in order to obtain standardized application conditions that can be adopted in different types of commodities, facilities, and conditions.…”

“…The eggs were newly hatched (one to two days old), and larvae and pupae were younger than seven days and three days old, respectively. The methods for obtaining the different life stages of T. confusum have been described in previous papers [ 13 , 15 , 19 ].…”

“…Four trials were conducted inside a sealed chamber (237.6 m 3 ) in which the nitrogen was introduced by using the system that is described in previous works [ 13 , 15 , 19 ]. For Trials 1 and 2, plastic Petri dishes (9 cm in diameter) were used, while for Trials 3 and 4, we used plastic cylindrical vials (2.5 cm in diameter, 9 cm in height).…”

Influence of Modified Atmospheres on Infestation of Stored Date Fruits by Ephestia cautella (Walker) and Stegobium paniceum (L)

“…As a result, death happens from an anoxic environment and dehydration. Thus, the most accurate expression can be "low oxygen" rather than "high nitrogen" (Navarro, 2006;Agrafioti et al, 2022). Given that the percentages nitrogen and oxygen in the atmosphere are roughly 78% and 21%, respectively, and the increase in nitrogen will result in a proportional decrease in oxygen, which will cause hypoxia or anoxia (Mitcham, et al 2006;Navarro, 2012 and.…”