Aluminum foil is a popular "garden hack" for repelling certain types of insects, particularly aphids and thrips, but its effectiveness is limited and specific. The theory is based on light reflection; when laid on the ground around the base of plants, the foil reflects sunlight upward onto the undersides of leaves where these pests like to hide. This confuses the insects' navigation and light-sensing abilities, causing them to move away. However, it does not "repel" larger insects like mosquitoes, ants, or spiders in any significant way. In fact, for mosquitoes, foil has zero impact as they are attracted to heat and carbon dioxide, not deterred by shiny surfaces. While foil can help with small, light-sensitive garden pests, it can also harm plants by reflecting too much heat, potentially scorching delicate foliage in peak summer. Furthermore, it is not a long-term solution as the foil degrades and becomes less reflective over time. It is a clever, short-term deterrent for specific agricultural pests but should not be mistaken for a general-purpose domestic insect repellent or a substitute for professional pest control.