What do newly hatched billbug larvae look like?

Newly hatched billbug larvae are typically legless and have a soft body. A key characteristic of these larvae is their feeding behavior; they burrow down into the plant stems, which is a critical aspect of their biology and impact on plants. This legless structure allows them to move through the plant tissues effectively as they consume the plant's cellular material, leading to potential damage or even death of the host plant.

The other options do not accurately depict the appearance of newly hatched billbug larvae. Small black beetles refer to the adult stage of the billbug, not the larval stage. Long green worms may confuse them with another type of pest, while pale, winged insects would typically refer to a different life stage or different insect entirely. Understanding the larval form of pests like the billbug is vital for effective pest management and control strategies.