Not quite. It is not fallacious to conclude the negative case in the presence of no evidence. In fact, it is good rational thinking.
Where the fallacy comes in when it becomes a matter not of the evidence but of the conviction. "I can't imagine such a thing as ghosts, therefore they cannot exist", "I don't understand evolution, therefore it cannot work", or any such state where your conclusion precedes your analysis, in a refusal to consider. It is not fallacious to examine the evidence, or lack of it, and come to a conclusion from there, so long as one is willing to revise one's conclusion based on further data.