Detecting insects in grain remains a weak point in silo operations and professionals are calling for a step change in performance. A series of interviews conducted with 7 silo managers and quality experts across France highlights a clear message: current detection methods are no longer sufficient given the operational and financial stakes.
Figure
1 Silo and ventilation system © ARVALIS
Silo managers highlight the limitations of their current practices.
Today, insect detection relies almost entirely on manual sieving, typically using a 2×2 mm square mesh. While widely adopted, this approach shows major limitations such as low sensitivity for early or low-level infestations, uncertain representativeness of samples and no ability to detect hidden infestations. Operators acknowledge that sieving may detect insects in roughly 80% of infested cases, but most agree that performance drops significantly at low-level infestations. The issue lies not only in the method itself, but also in sampling practices, which may not reflect the actual condition of a grain batch.
The frequency of insect checks depends heavily on the type of facility. In inland silos, detection is not systematic, mainly carried out at harvest, whereas collection and dispatch sites carried more regular controls and port silos carried systematic checks on both receipt and shipment. Wheat and barley are the primary focus, while corn is rarely monitored due to lower perceived risk.
Failing to detect an infested batch can have serious financial consequences. One reported example highlights a €30,000 loss linked to late detection during barge loading. The risk is particularly high in port silos, where large volumes and multi-operator storage increase liability. Despite this, costs of non-quality are rarely quantified.
“First
detection, then quantification,” say silo managers.
The expectations for new insect detection technologies are clear and pragmatic. First and
foremost, operators are looking for a simple and reliable answer to a basic question: are
insects present or not? Quantification and species identification are considered secondary, as operational decisions are generally based on presence alone. However, any new method must significantly outperform manual sieving, with higher sensitivity the ability to detect at least 3 insects per kilogram - currently the lowest acceptable threshold in port silos - and the capacity to identify hidden infestations that remain undetected today. At the same time, specificity is critical: false positives are seen as unacceptable because they can lead to unnecessary batch rejection and commercial disputes. Finally, any solution must fit smoothly into existing workflows, with a clear preference for technologies that can integrate with equipment already used on site, such as multi-parameter analyzers.
A real market exists for such solutions, with an acceptable investment estimated at around €20,000, although profitability will depend on the size and throughput of the site.
Nevertheless, adoption will be driven less by innovation itself than by proven performance in real conditions. In this context, there is strong interest across the sector for faster and more reliable insect detection at grain intake, but expectations remain uncompromising: methods must be more sensitive than sieving, deliver virtually no false positives, and remain simple to operate. Without meeting these requirements, new technologies risk being rejected in the field, just like previous attempts. For grain storage professionals, the message is clear: better detection is needed, but only if it can be fully trusted.
Camille Harel, ARVALIS
Check the DODILog pilot on insect detection in grain via NIRS