The drop in temperature during October can lead to a surge in pest populations as they seek out warm environments, often within your thriving plants. Common culprits include aphids, caterpillars, and spider mites. Fungal diseases such as powdery mildew or blight also pose risks due to increased humidity. Begin by inspecting your plants regularly for signs of infestation or illness—discoloration, wilting, or holes in foliage are tell-tale indicators.