Answer:
Chromoblastomycosis
Explanation:
Based on the information provided within the question it can be said that worker is most likely suffering from Chromoblastomycosis. This is a type of infection that follows the description mentioned, and is caused by fungi entering the subcutaneous tissue after a field tool or vegetative material like a thorn or splinter pierces the skin and creates an opening for the fungi. Just like what happened to the worker.