Thrips are small insects that feed on plant sap. These pests can cause significant damage to plants by sucking the water and nutrients out of leaves. Leaves will turn yellow and may eventually fall off the plant. Thrips can also form colonies on other plants nearby, which can lead to a lot of leaf damage. One way to prevent thrips from feeding on your plants is to keep them covered in debris. This will reduce their access to sap and foliage. Also, make sure your plants are watered regularly so they don't get too dry. Prune back any growth on your plants that is close to the ground, as this will provide more hiding places for thrips. If you notice leaves wilting or falling within a few days of being bitten, then it is likely that thrips are causing damage. Remove the affected leaves and contact a professional if necessary.