Mother Nature asserts herself in every garden: weeds, insects, disease ... they’re all waiting to take control, and although you can’t stop her, the first step in combating her is recognizing the signs and vigilantly watching for them. Here’s a primer.
Dropping a hint: The first signs of a tomato hornworm's chewing damage are their droppings, which are easier to see than the green caterpillars themselves. The caterpillars normally start eating at the tops of plants. Pick them off and destroy them.
But, if the hornworm is has tiny white "Tic-Tac" shaped parasites hanging off its body, leave it alone. This Braconid parasite is a beneficial and important factor in hornworm control.
Late fruiters: Assuming you did not give the plant too much Nitrogen, lack of bearing fruit may be weather-related: nighttime temperatures that remain above 70 degrees or below 50 interfere with pollination. Fruit set can also be hampered by irregular watering.
Rot Bottom: Blossom-end rot, so called because the bottom is where the flower was before the fruit began to grow, can appear as leathery and sunken, or be watery-looking. The end is discolored, and dark. The cause: not enough calcium, caused by water stress. Some gardeners work lime or calcium into the beds as a preventive measure.
Greenbacks: On a tomato’s stem end, having a “greenback” doesn’t signal a bumper crop, it means the area remains hard, green and unripened. Too much sunshine can sometimes be the culprit.
Seeing Spots: Various fungal diseases, cankers, viruses and bacterial conditions can show up as spots on tomato skin. If your tomatoes get anthracnose (sunken round spots that go dark in the middle for a bull’s-eye effect), alternaria canker (a.k.a. blight, sunken gray-brown marks on fruit, accompanied by plant lesions), or black mold and ghost spot (watery spots with dark centers), crop rotation might have helped prevent it, and is a must next year.
Tomato foliage can also experience all manner of spotting, and many such afflictions are symptoms of the same cankers, blights, fungi and viruses.
Sometimes leaves fall off from the bottom up, other times it’s from the top-down. Bacterial wilt is a top-down deal, while fusarium and verticillium begin at the bottom of the plant. Apply two inches of compost, then mulch lightly. A barrier of clean mulch applied at planting time can reduce some spores that splash up from the soil onto plants.
