I was recently asked the question "What is the difference between a fruit and a vegetable?" It is a common question, usually pertaining to tomato classification, so I thought I would answer it here to satisfy everyone's burning need to know.
Botanically speaking, the word vegetable means "pertaining to plants." By definition, a fruit is the result of an effort. The fruition of the plant's effort is making seeds to reproduce. The apple you eat is the ovary that produced seeds, and the reason it is sweet, is to disseminate the seeds through whatever eats it.
Culturally speaking, fruits are sweet, desserttype food. Almost always the actual fruit of the vine or tree can be eaten raw out-of-hand.
Vegetables, on the other hand, often need some preparation and may be sweet, (like corn), but usually not a dessert. They are not necessarily a fruit of the plant but instead some other part of the plant. Some examples are: a leaf (lettuce, cabbage), a stem (celery), a root (carrot), a seed (beans), a petiole [that little stem between the leaf and the branch] (rhubarb), a flower (broccoli), specialized stems for overwintering-bulbs and tubers (onions and potatoes).
So the question remains, is a tomato a fruit or a vegetable? The answer is yes. Botanically it is a fruit, in fact a berry. Culturally, however, it is treated as a vegetable. So there you have it. As the song goes "...let's call the whole thing off."
Speaking of vegetables, there are a couple of rascals to watch for in the hot summer garden. First I would keep a close eye on spider mites. They are very small but can do a lot of damage. They are especially bad on tomatoes and marigolds but also can affect other crops like beans and even okra.
Mites like hot, dry conditions, so this summer has been prime for their proliferation. Look for them on the underside of the leaf. They are very small, so a magnifying lens can be helpful. Look for a few webs and little red dots with legs underneath and little dots on top where they have been feeding. A lot of mites make a lot of little dots, giving a russeted appearance to the leaves. Insecticidal soaps can be used but usually are not very effective. Other chemical deterrents are Malathion or Diazinon, but probably the best recommendation is Kelthane.
These chemicals are usually pretty effective, but keep a few things in mind. Scout for mites to catch them before numbers build so that the plants are not damaged too badly. Next, make sure to spray the underside of the leaf to get where the mites live. And keep scouting because a second application is often necessary. As always make sure you read the label for rates and recommendations, and be careful when using chemicals.
The second critter to watch for is the squash bug. They are dark, gray colored bug about three-quarters of an inch long usually found under squash, pumpkin and melon vines. These insects feed on these plants by sucking the juice so when large numbers build up in hot weather, it is often more than the plants can take. Squash bugs are very tough when mature but not too hard to kill when they are young. They hatch out as nymphs, as opposed to larvae, and go through several "instars," or stages of growth. The younger instars look like the older except for size and color (they are white to light gray).
Again, scouting gives you the edge on spraying when lots of eggs have hatched, so you can get the most bang for your buck. Sevin, as most of you may well know, is not very effective. The most recommended chemical for homeowners is Thiodan. However, if you are a licensed applicator, Asana is an effective restricted use pesticide. Make sure you get under the leaves because squash bugs like to hide in the shade... but don't we all? Happy gardening!