Note: never handle cigarettes or other tobacco products while planting or harvesting tomatoes. Tomato plants are susceptible to tobacco mosaic virus, harmless to humans but dangerous for related plants.

This phenomenon, known as "blossom drop," is usually caused by rapidly changing temperatures, for instance, cool nights and hot days. It can also occur when the air is very dry. There is no practical preventative.

When fruit exhibits blotchy ripening, it's usually caused by too much shade and cool temperatures. The tomato may not mature completely.

When large holes appear in your tomatoes, look around on the plant for a hornworm. This finger-sized, light-green caterpillar will eat its way around the whole tomato patch. Picking hornworms off is usually the easiest way to eliminate them.

"Leaf roll" is a condition that affects only the leaves. Your tomato fruits will not be affected. No disease is involved.

Tomatoes that feel puffy when mature may have suffered from a pollination problem due to extremes in temperature. Depending on the weather, little can be done to correct temperatures. Try to protect the maturing tomatoes from extreme hot and cold.

This condition is called sunscald. The light patches will probably end up rotting. Sunscald can be prevented by choosing plants that produce the most leaf coverage. Do not trim leaves.

When your perfect specimen suddenly turns black and rotten on the bottom, your tomato is suffering from blossom end rot. This problem can be prevented by keeping the soil consistently moist. Mulching your plants will help prevent total drying out.

Tomatoes that show this "zippering" have been subject to cold temperatures that resulted in a pollination problem. Protect young plants from the cool early spring air. Also, grow the varieties of tomatoes that are cool-temperature hardy.

The "shoulders" of your tomato may remain light green (the area around the stem). There is no disease involved. Choose hybrid varieties to grow (these have had this condition bred out), and pick tomatoes while still all green to ripen indoors on the windowsill.

Tomato blossoms are sometimes damaged by winds and cool temperatures, which results in a tomato with scarring known as "catfacing". The fruit is fine to eat. No disease is involved.

When leaves resemble lace more than leaves, your tomato patch probably has flea beetles. You can see the flea-size beetles jumping from plants when they're disturbed. Spray your plants with Schultz Fruits & Vegetables Insect Spray made with botanical pyrethrins. It's safe to use on edibles up to the day of harvest.

The small tomato fruitworm is probably the culprit behind small holes in fruit and flower buds. They may be sprayed with Schultz Fruits & Vegetables Insect Spray, made with natural pyrethrins. It's safe to use on edibles up to the day of harvest.

Long tunnels in leaves are usually the result of a little worm-like leaf miner. Spray with Schultz Fruits & Vegetables Insect Spray.

Seedlings mysteriously chopped off near the soil may have been attacked by deer, rabbits, or tiny cutworms. Fencing will keep out the first two, larger critters. And a tiny collar made of a paper towel roll section can be placed around the seedling at the time of planting to prevent easy access by cutworms (submerge the collar about 1 inch into the soil, with about 1 inch above the soil).

Aphids love rose bushes, and it sounds like your plants have them. Aphids sink their sucking mouth parts into rose stems and remove the juices. Ants herd aphids like sheep and harvest aphids' sticky-sweet "honeydew" residue for food. Spray your plants in the early morning with Schultz Roses & Flowers Insect Spray, made with botanical pyrethrins.

Powdery mildew is a very common rose fungus that takes hold when days are hot but nights are cool; when plants are too close for adequate fresh air circulation; or when roses are watered often at night. Water early in the day to allow rose leaves to dry thoroughly before nightfall. Consult the American Rose Society at www.ars.org for recommendations.

This reddish, warty-looking bump is rust, a fungal disease that may spread quickly over entire leaves. Rust is generally active after long periods of dampness. Remove damp leaves from around plants to help keep rust spores from spreading. Watering early in the day, which allows rose leaves to dry thoroughly before nightfall, helps lessen fungal diseases. Consult the American Rose Society at www.ars.org for recommendations.

When webbing appears on almost any plant (unless you see a beneficial spider nearby), you can be sure the plant has spider mites. These microscopic members of the spider family feed on the juices of plants, whereas large spiders help us by feeding on harmful insects. Spray spider mites with Schultz Roses & Flowers Insect Spray, made with botanical pyrethrins.

Black rings on rose leaves indicate black spot, another fungal disease. Watering early in the day, which allows rose leaves to dry thoroughly before nightfall, helps lessen fungal diseases. Consult the American Rose Society at www.ars.org for recommendations.

Promising blooms that suddenly turn freckled and start to deteriorate usually have thrips. They feed and live almost exclusively inside the blooms. Schultz Roses & Flowers Insect Spray is effective against thrips.

Your plant is probably too dry, and may be in a location that's too hot. Submerge the whole pot in some lukewarm water and allow the soil to soak. Water it more often, for instance, once every ten days or so. Consider a location in a cooler spot with good air circulation.

Overwatering is probable -- the number-one killer of plants. Allow most plants' soil to dry out slightly between waterings. Check the soil with your finger down to about a 1/2-inch. Water only when the soil feels dry.

Spider mites have invaded! Under a gentle spray of lukewarm water, wash your plant's leaves. Then spray as needed with Schultz Houseplants & Gardens Insect Spray, made with botanical pyrethrins from chrysanthemum flowers. Keep checking for more webbing over the next few weeks. Keep newly purchased plants away from your regular plants for three months as a quarantine to stop the spread of spider mites.

Your plants have a case of aphids. The sticky substance is the aphids' residue, which sometimes attracts ants that like to eat it. Wash plants under a gentle, lukewarm spray of water. Spray as needed with Schultz Houseplants & Gardens Insect Spray, made with botanical pyrethrins from chrysanthemum flowers.

Sounds like mealybugs. Try new Schultz Insect Killer for Whiteflies & Mealybugs. It's a tetramethrin aerosol that quickly kills the hard-to-eliminate mealybug, plus dozens of other pests.

When otherwise healthy violets aren't blooming, it may be because of inadequate lighting. African violets need filtered daylight (or fluorescent lighting placed 14" above them) for about 10-12 hours a day to produce blooms. Your plants might also need more nutrients. Feed your African violets every time you water with Schultz Liquid Plant Food for African Violets.

Overwatering is the probably the cause of mushy stems and limp leaves. Your African violets may even be dropping leaves. When too much water is present in the soil, fungal diseases have their day and can eventually kill the African violet. Allow your soil to dry out somewhat between waterings. Keep your soil moist but not soggy. Never allow your violets to sit in water for longer than 30 minutes.

Sudden yellowing of a usually healthy African violet may indicate natural gas in the environment. Other symptoms include unexplainable leaf drop or blossom drop. Your gas stove, furnace, or dryer may be leaking. Move your plants away from the gas source, and check out your gas lines.

Underwatering is just as common as overwatering. Dry soil or dry air can cause the symptoms described. Try watering the entire root ball by soaking the plant in a sink (always use lukewarm water). Others prefer to water African violets by setting the plants in saucers of water for about 30 minutes. To increase humidity, consider setting each pot in a saucer containing enough gravel so the pot sits above the water level and does not absorb water from the saucer. For more tips on watering methods, visit the African Violet Society of America at www.avs.org.

When gray powder appears on previously healthy blooms and leaves, chances are your plants have powdery mildew. As with most fungal diseases, powdery mildew is in the air anyway, but starts to take over when fresh air circulation is inadequate. Remove the affected leaves and blooms. Wash your hands as you go to prevent spreading the mildew. Set your African violet pots farther apart so that fresh air circulates between them.

Mealybugs look like little cottony balls on stems and leaves. They spread quickly, so isolate your mealybug victims from your healthy plants. New Schultz Insect Spray for Whiteflies & Mealybugs is an effective insecticide for mealybugs. For more information, visit our Products page.

Brown spots on leaves are usually caused by sunlight burning through water droplets left on leaves, so try to keep your African violets' leaves dry and clean. Never spray velvety leafed plants like African violets with water.

Pale spots on flowers are also caused by water drops. Never spray violets with water. And if you're washing off leaves and flowers as part of insect control, allow the African violet to sit away from its regular brightly lit location while it dries.

These symptoms indicate cyclamen mites, a type of spider mite that is impossible to see without a strong magnifying glass. Spray with Schultz Houseplants & Gardens Insect Spray, made with natural botanical pyrethrins. It may be impossible to eliminate all cyclamen mites. Many growers simply throw the plant away. Be sure to isolate sick plants to keep the mites from attacking your healthy plants.

When African violets seem to be growing slowly, or they just don't look very healthy, it may be time to repot. Choose a pot about the same size as the original (African violets like to be slightly potbound). The experts recommend repotting annually, or even every six months, to keep African violets' soil fresh. Please visit our Repotting section for tips on repotting African violets with Schultz Potting Soil Plus for African Violets.

One of the tiniest insects is thrips, a menace to many blooming plants. Experts recommend treating all African violets in a collection at one time because chances are good they are all playing host to this almost invisible insect. You will have to remove all blooms and buds from your plants and then spray with Schultz Houseplants & Gardens Insect Spray. Check new blooms later for any tiny movements and re-apply insect spray as needed.

Crown Rot is killing your plant. It is caused by too much wetness in the soil. Avoid fungal diseases with good watering practices. For example, never allow plants to set in saucers of water for more than 30 minutes. Unfortunately, there is no cure. Discard your plant.