Effects of threshing and storage conditions on post-harvest insect infestation and physical characteristics of maize grain

Maize is the most significant cereal crop in Ethiopia in terms of production, and it is essential in terms of food security. However, ineffective threshing and storage of maize grain had a substantial impact on its physical attributes and loss. This study aimed to investigate the impact of threshing, and storage conditions on the physical properties and insect infestation of maize grain during storage. For this, a freshly harvested maize grain of BH-540 variety was used. Maize was threshed at two moisture content levels (17, and 23%) using two threshing methods (hand & mechanical). After threshing, the grains were dried to safe moisture content (13%) for storage using a solar bubble dryer and stored in five different bags (Purdue Improved Crop Storage bag, GrainPro, ZeroFly, woven polypropylene bag with plastic liner, and woven polypropylene bag) at a room temperature for 6-months. Each post-harvest loss indicator parameter and the physical properties of the grain were measured over 6-months. Minitab software (version 19.2) was used to analyze the data. During threshing, the highest broken kernel was observed on maize grain threshed mechanically at 23% moisture content (44.00). The threshing and storage conditions showed a significant effect (p < 0.05) on all post-harvest loss indicator parameters. The maximum total number of adult live weevils (227.67 adult/kg) were observed for maize threshed mechanically at 23% moisture and stored in a woven polypropylene bag for 6-months. Similarly, maize threshed mechanically at 23% moisture and stored in a woven polypropylene bag had the highest weight loss percentage (5.45%), and grain damage (20.06%) after six months of storage. No loss was observed in both threshing conditions stored in hermetic bags and all physical properties of maize have remained good during the six months of storage. Generally, to reduce the high percentage of postharvest loss of grains, grains should be threshed and dried immediately using appropriate artificial dryers, and stored in hermetic storage structures.