What form do thrips eggs take when laid on leaves or stems?

The correct answer identifies thrips eggs as having a white bean-shaped form. This distinctive shape aids in their identification, setting them apart from eggs of other pests that may appear round, sticky, or gelatinous. Thrips typically lay their eggs in the plant tissue, often on leaves or stems, which helps in concealing them from potential predators.

Other forms mentioned in the choices, such as being round and sticky or long and thin, do not accurately represent the morphology of thrips eggs, nor do they align with the biological characteristics specific to this pest. The shape and appearance of the eggs can influence their survival rates and the methods of pest control that might be applied, making recognition crucial for effective management. By understanding that thrips eggs are white bean-shaped, pest control professionals can better identify infestations and take appropriate action to mitigate plant damage.