Question
We live in Hawaii where it rains a lot.  we have one yellow pear tomato plant.  The top four or five branches are green and healthy and blooming.  The bottom branches are turning brown and curling up one by one progressively from the bottom.  It looks like there is new growth at the joint where the dying branches are falling off.  What is it? and how do I fix it.

Answer
Donna, it is not uncommon for bottom leaves to yellow or brown in dry conditions. This condition is even more prevalent when gardeners water often but shallow. When this occurs, the roots are reaching to the surface for water. It is much better to water very deeply once or twice per week than to water shallow everyday.

If, however, as you described, your area is receiving ample rainfall, the problem may be that a fungus disease has infected your plants. The most common types are fusarium wilt and verticillium wilt. If the plants have contracted either of these, the leaves will gradually curl and drop off. Blight, on the other hand, results in blackened patches on the leaves. Most current day hybrids are resistant to these diseases. However, if you are growing heirlooms or open-pollinated varieties, disease is a stronger possibility.

To prevent the disease from advancing, spray the plants with any over-the counter fungicide. I personally use copper-based fungicides as a preventive measure by spraying once every two weeks. You can purchase these products at any reputable garden center or through an on-line company such as Gardens Alive.

I would also advise you to mulch the plants heavily with aged grass clippings or straw. This will not only prevent soilborne diseases from splashing up onto the leaves, but it will also retain the moisture which means less need for watering should the rains subside.

I hope this helps.  Please write again if I can be of further assistance.

Regards,

Mike