What causes damage to developing ovaries in sorghum heads?

The correct choice highlights the impact of sorghum midge small maggots on developing ovaries in sorghum heads. These small maggots, which are the larvae of the sorghum midge fly, specifically target the developing reproductive structures of the sorghum plant. When the female midge lays eggs on the florets, the emerging larvae feed on the ovaries, leading to significant damage. This feeding affects the plant’s ability to produce viable seeds, which ultimately reduces yield.

Other choices, while they may involve pests or diseases, do not directly harm the developing ovaries in the same manner. Green bug infestations, for example, can reduce overall plant health and productivity but do not specifically target the reproductive structures. Feeding by soybean thrips can damage foliage but is not a primary threat to sorghum ovaries. Bacterial infections can lead to various plant diseases but typically do not cause the kind of direct damage to ovaries that the sorghum midge larvae do. Understanding these distinctions is crucial for effective pest management and maximizing crop yields.