Thrips are a group of small, wingless insects that suck juices from plants. They can cause extensive damage to foliage by sucking the fluids and nutrients out of leaves. This can lead to wilting, reduced growth, and eventually death of the plant. Thrips are most commonly found on outdoor plants such as flowers, fruits, and vegetables. They usually attack plants in cool weather, but they can also infest warm-season plants if conditions are right. The damage caused by thrips is usually visible as tiny dots or streaks on the leaves. Thrip victims may also experience a sour odor on their foliage. In extreme cases, thrips can even cause entire leaves to fall off the plant.