Modeling of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) based on historical weather data indicates aeration is effective for management of wheat stored in Greece

Authors: Morrison, William - Rob; ARTHUR, FRANKLIN - Retired ARS Employee; ATHANASSIOU, CHRISTOS - University Of Thessaly; LAMPIRI, EVAGELIA - University Of Thessaly; WILSON, LOYD - Texas A&M University; YANG, YUBIN - Texas A&M University; WANG, JING - Texas A&M University

Submitted to: Computers and Electronics in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/2022
Publication Date: 4/8/2022
Citation: Morrison Iii, W.R., Arthur, F.H., Athanassiou, C.G., Lampiri, E., Wilson, L.T., Yang, Y., Wang, J. 2022. Modeling of Sitophilus oryzae (L.) (Coleoptera: Curculionidae) based on historical weather data indicates aeration is effective for management of wheat stored in Greece. Computers and Electronics in Agriculture. 0168-1699. https://doi.org/10.1016/j.compag.2022.106926.
DOI: https://doi.org/10.1016/j.compag.2022.106926

Interpretive Summary: It is increasingly important to shift management of insects after harvest away from fumigants to nonchemical alternatives. One potential nonchemical alternative is grain aeration, whereby a low flow current of air is circulated from outside through a grain mass in order to cool the temperature of the grain, reduce development of insects, and protect commodities from damage. Grain aeration has largely been assumed to not be feasible for southern Europe, despite its importance in producing, storing, and processing stored wheat in the European Union. An important stored wheat pest to consider is the rice weevil, which is commonly found at food facilities in Greece. In this study, when we analyzed the climatic patterns from 10 year historical weather information, we found there were three grain aeration zones in Greece, ranging from warmest, to intermediate and coolest as one moves up in elevation and away from the coastline. In evaluating multiple scenarios of aeration in the warmest zone, we found that when activation of aeration uses an outside threshold of 60°F starting on 15 July or through aeration activated at an external temperature of 70°F, rice weevil populations were suppressed compared grain with no aeration. However, in this warmest part of Greece, it is likely an additional fumigation will be needed to control insects, but using aeration may delay when a fumigant is required. In the intermediate and coolest regions of Greece, all aeration scenarios equally suppressed rice weevil growth and prevented the need for fumigation compared to when no aeration was used. Our results indicate that aeration recommendations may need to be tailored to specific climatic zones, even in a relatively small country like Greece because of its complex topography. Importantly, aeration is predicted to be an effective, nonchemical alternative tactic by which to control rice weevil populations in Southern Europe.

Technical Abstract: A modeling simulation study was conducted to determine the feasibility of using aeration to manage Sitophilus oryzae (L.) in wheat stored throughout the country of Greece. Daily high and low temperature data were obtained for sixteen representative sites in Greece from 2010–2019, and averaged to predict hours below temperature thresholds of 15', 18', and 21' from August–November. Based on climate, the sixteen sites were classified into three distinct aeration zones. Zones were associated with differences in latitude and elevation. Web-based modeling developed predictions for S. oryzae population growth in unaerated wheat, wheat aerated immediately after the start date of 15 July, and wheat aerated based on the accumulation of temperatures below the 15' , 18', and 21' thresholds. The optimal aeration scenarios for inhibition of S. oryzae growth in wheat stored in the warmest Zone 1 were immediate aeration or aeration at 21', but additional fumigation inputs may be required in this zone. Immediate aeration or aeration at 18 and 21°C were the most optimal scenarios for wheat stored in Zone 2, an intermediate climatic zone. For the coolest Zone 3, any aeration scenario would be feasible. For all zones, predicted S. oryzae populations in unaerated wheat would increase exponentially in late autumn to catastrophic levels, causing extensive economic damage. Our results can be used to develop wheat management using aeration in Greece, and may possibly lead to reduced reliance on phosphine for control of S. oryzae.