Gardeners wrestle with problems growing tomatoes

Vegetable problems seemed to be on gardener's minds this week.

Damaged tomato leaves: The culprit eating the leaves is the tomato hornworm, one of the largest caterpillars, measuring 4 inches in length. The prominent "horn" on its rear gives it the name. It quickly defoliates tomatoes, potatoes, eggplants and peppers. You'll see damaged leaves on top of plants before seeing the perpetrator. Hornworms are difficult to see because of their coloring. They are not much for heat or sunlight, so they feed inside the plant during the day but on the outsides at dawn and dusk.

Do one of the following to control them: Close your eyes and handpick them; snip them in half; place them in a bucket of water or use Bt, an organic compound. Finally, remove all damaged foliage so you know if you are conquering them.

Sickly yellow, stunted tomatoes: This is a disease called curly-top virus because it causes leaves to curl. Sugar beet leafhoppers that winter in southern Arizona make their trek to the beet fields of Washington. They need nourishment along the way, so they feed on your tomatoes. As a way of saying thanks, they inject a virus into the tomatoes. If you have infected plants, remove them. Deter infecting other plants by shading your tomatoes, because the insect won't go under shaded areas. Nurseries sell shade cloth, and the added shade will prevent your tomatoes from splitting.

Tomatoes naturally curl: This is a natural phenomena believed brought on to slow down photosynthesis because of our excessive sunlight. The plants are OK.

Something eating mint: If you find leaf damage on your mint and can't find the offender, suspect a cat. Veterinarians tell me that mint has similar ingredients of that found in catnip, so it can prove tempting to some cats.

Damaged beet leaves: Flea beetles feed on beet leaves and may go unnoticed except for the damage left behind. This beetle feeds on a wide range of vegetables, stunting their growth. For control, eliminate weeds near the garden to deprive them of food and clean up areas where they seek protection. Cover veggies with shade cloth until the plants are established. Interplant with other crops such as tomatoes and broccoli to reduce their feeding sites or use an organic compound called neem, directing it to the underside of leaves.

Bottomless radishes: They will not make bulbs if they are too crowded. If overfertilized, they'll grow only tops. They also won't make bulbs if you didn't provide enough phosphorous prior to planting and/or if temperatures get above 85 degrees, which isn't a big problem right now.

Hot radishes: They will become hot if you plant them in poor soils without organic matter, if they stress for water and nutrients to bring on radishes or if you let them get too old and/or if temperatures get over 85 degrees. So far we've had good temperatures, but we're moving into the no-plant radish zone until fall.

Forking and twisting carrots: Compacted soil or rocks interfering with the developing roots generally bring on forking. Also, planting too thick brings on the twisting carrots if you didn't thin them out.

Sticky white stuff on rosemary: Spittlebugs cause frothing, but it won't harm this herb. If these bugs bother you, direct a strong jet of water at them to wash off the sticky stuff. The now-exposed insect dies quickly.

Dichondra taking over Bermuda: Dichondra grass is very aggressive if overwatered. It can be even more aggressive if planted under shade. Bermuda does not compete with shade or dichondra at all. Cut back the watering and if shade is a problem, thin out the trees so you get light coming through them. We call this dapple shade.

Linn Mills writes a garden column each Sunday. You can reach him at linn.mills@springspreserve.org or call him at 822-7754.