Brown streaks on stems of healthy basil
I just bought a sweet basil plant that was hydroponically grown. I plan to transfer it into my hydroponics system once I finished building it. However, 2 days after, the stems near the sand began turning into brown streaks, became smaller in diameter, and softer. I did not overwater it as I only water it when the sand is dry. I had to support the plant using skewers in order to make it stand upright as it was drooping. The leaves are all green and healthy, no shedding of leaves at all.
I had given it some sunlight but not too strong as it was indoors
I read online that sweet basil is very susceptible to diseases like fusarium wilt. Is it really fusarium wilt, or is it because of some other reasons?