This question requires identifying the factor that does NOT cause biotic loss during grain storage. Biotic losses are caused by living organisms, while abiotic losses are caused by non-living factors.

Understanding Biotic vs. Abiotic Grain Losses

In grain storage, losses can occur due to two main categories:

• Biotic Factors: These are living organisms that damage or consume stored grains. Examples include insects, rodents, mites, and fungi.
• Abiotic Factors: These are non-living environmental conditions that degrade grain quality or cause loss. Examples include temperature, humidity, inappropriate moisture levels, and physical damage.

Analyzing the Options

Let's examine each option in the context of biotic loss:

• Loss by rodents: Rodents (like rats and mice) are living organisms that directly consume and contaminate grains. This is a biotic loss.
• Loss by inappropriate moisture: Moisture content is a non-living environmental factor. High or inappropriate moisture levels can lead to spoilage, fungal growth (which is biotic, but the *moisture* itself is abiotic), and degradation of grain quality. This is an abiotic factor influencing loss.
• Loss by insects: Insects (like weevils and beetles) are living organisms that infest and damage grains, reducing quantity and quality. This is a biotic loss.
• Loss by mites: Mites are tiny living organisms that can infest stored grains, causing damage and spoilage. This is a biotic loss.

Conclusion on Grain Storage Losses

The question asks for the factor that is NOT a biotic loss. Based on the analysis, inappropriate moisture is an abiotic factor, not a biotic one. While it can contribute to fungal growth (biotic), the moisture level itself is a physical condition.

Therefore, loss by inappropriate moisture is the correct answer as it stems from an abiotic cause.