Weed, insect, and disease control may also be required for pastures. A healthy, productive pasture will resist invasion from most poisonous weeds and provide good quality forage. When pastures are overgrazed, horses will eat the grass and legume species down to the soil, which allows weeds to take over.
1 Melasma can be triggered by birth control pills because it increases hormones throughout the body. # 2  This is one of the most common causes of melasma. 3  Pregnancy: During pregnancy the body will become very hormonal and skin conditions like acne vulgaris and melasma/chloasma become very common.
Causes and Symptoms of Melasma. Melasma shows up in the form of brown spots or patches on the cheeks, forehead, upper lip and nose. It is most common in women during their productive years and it tends to with olive skin that tans easily. My friend fits this risk factor because she always looks tan, even in winter.