What is the resistant survival structure associated with Damping-off?

The correct answer is oospores. Oospores are the thick-walled, resting spores produced by certain fungi, including some that cause damping-off diseases. These structures allow the fungus to survive adverse environmental conditions, such as drought or extreme temperatures, by remaining dormant in the soil until favorable conditions for germination return.

In the context of damping-off, which affects seedlings and young plants, oospores play a crucial role in the life cycle of the pathogens by enabling their persistence in the soil between crop cycles, thereby leading to continued infection of susceptible plants when they emerge.

Other structures, such as zoospores, are involved in the motile stage of certain fungal pathogens that can cause infection, but they do not have the same capability for long-term survival as oospores. Chlamydospores are also a type of survival spore, but they are produced by different fungi and may not be directly related to damping-off. The term "poda" does not correspond to a known survival structure associated with damping-off. Thus, oospores are specifically recognized for their role in the resistance and survival of pathogens associated with damping-off.