The low chemical activity of the inert gases is due to the fact that their outermost, or valence, electron shell is complete, containing two electrons in the case of helium and eight in the remaining cases.
Often only one side of a plant is affected at first, but symptoms eventually spread. Tomato Leaf SpotâSeptoria lycopersici Fruit is not affected, although sunscald can be a problem due to foliage loss. Numerous brown spots on leaves, each about 1/16 inch in diameter. They do not have a yellow halo and they do have black specks in the center. First symptoms are usually on lower leaves after the first fruit sets.
Tomato plants are susceptible to pest damage. The leaves and fruit of the plant attract a variety of bugs, and these insects are capable of destroying your garden tomato crop. Some pests eat holes in the leaves and bore into the fruit, while others suck the juice from the leaves and stems, weakening them. Still others feed on the roots of the tomato plant.