Why would the blooms on my eggplant suddenly drop off? Is this a sign of something bad?
This article should help: https://www.gardeningknowhow.com/edible/vegetables/eggplant/what-to-do-for-eggplant-blossoms-drying-out-and-falling-off.htm
My eggplants are turning yellow and they are still very small. If it is bacteria wilt or one of the other causes listed, how do I fix it?
Once a plant is infected with bacterial wilt, there is no cure. If you have soil that is contaminated with bacterial wilt, you need to either make sure not to plant anything from the nightshade family (e.g. eggplant, tomatoes, potatoes) for at least 2 years or you can solarize the location. Here are directions for solarizing: https://www.gardeningknowhow.com/garden-how-to/projects/how-to-solarize-garden-beds-to-eliminate-garden-pests-in-the-soil.htm
If it is a fungal issue, you can usually treat the plant with neem oil. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
My eggplants are breaking at the main stem because of the weight. They are not yet ripe enough to harvest but are too heavy for the branch. There are too many branches to put in a post. Should I use cages to support the branches next year? Is that unheard of or just not good?
Anytime you are growing eggplant, you want to stake the plants up to support the heavy vegetables. The use of tomato cages are preferred. However, you can use metal or wooden stakes as well.
I read that eggplants are perennials. What do I need to do to make sure mine comes back next year? Do I just cut it back as with other perennials?
Although eggplant is a perennial, it is more commonly grown as an annual. Generally, these heat-loving plants need to be protected by cool temps, especially freezing weather or else they will die. They can be pruned back in fall but it's probably more efficient to just get new plants. Here is an article that you may find helpful: https://www.gardeningknowhow.com/edible/vegetables/eggplant/growing-eggplant.htm
I just started picking my eggplants but some of them have holes in them, about 1/4 of inch round and 1/2 inch deep in the flesh. There are no visible bugs to be found. Could you help me? Could this be slugs?
Normally slugs focus more on the leaves rather than the fruit, though I guess it could be possible. It could also be some type of animal, like raccoon. However, there are many insect pests that feed on eggplants, including tomato hornworms. Try using neem oil. It's safe to use and is both an effective pesticide and fungicide. These articles should help: https://www.gardeningknowhow.com/edible/vegetables/eggplant/eggplant-problems-eggplant-pests-and-diseases.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
My eggplants are yellow and blossoms turn brown and fall. How to treat?
If it truly is wilt, there is nothing you can do for the plants. They need to be removed and destroyed and you should not plant any nightshade plants there for at least 2 years because the disease will affect those plants as well.
But, what you describe could also be caused simply by too little water. Try increasing water to the plants to see if that improves their condition.
My eggplant plant has tons of flowers but no fruit. Can you tell why? Also, how can I get the fruit to come?
Are they falling off? If so, this article will help: https://www.gardeningknowhow.com/edible/vegetables/eggplant/what-to-do-for-eggplant-blossoms-drying-out-and-falling-off.htm
It may be a pollination issue. Since they are similar to tomatoes, this article on hand-pollinating should be helpful: https://www.gardeningknowhow.com/edible/vegetables/tomato/pollinate-tomatoes.htm