I did a quasi-scientific test this year with my eggplant. I split up a six pack of plants and planted some of them with black plastic mulch and some of them without. The differences between them are remarkable: the plants that had plastic mulch are about 50% larger (taller & wider, with bigger leaves) and have given me more fruit to harvest. I was able to harvest much sooner (and thus able to enjoy more Szechuan eggplant and baba ghanoush .
Of course, this isn’t really a scientific test. The plants are in different garden beds, and various things could be different such as the soil, the sunlight, the watering, and the amount of attention I’ve given them. They also have different neighbors (peppers vs. cucumbers & broccoli). And I only tried it with the globe-type eggplant (I didn’t split up the ichiban). But, it does seem promising, doesn’t it?