Issue: August 27, 1997

Old lombardy poplar sick

We have a large (70 ft) Lombardy Poplar which is probably 40 years old. For the last 2 years it gradually sheds its leaves beginning about June and some branches in the lower reaches appear dead. The neighbor across the street has a smaller Lombardy Poplar (50 ft) and it's nice and leafy green. Our tree has no obvious signs of disease or damage other than previously mentioned. We live in the North Valley, in Los Ranchos de Albuquerque. We don't go out of our way to water it. 2 smaller trees nearby are in good health. Has the tree reached the end of it's life span? What can we do to rejuvenate it? Thanks for your advice.

Forty years is pretty old for a Lombardy Poplar here in Albuquerque. There are probably other factors involved, but age may certainly be a significant consideration. There are borer insects and canker diseases which can attack and injure or kill poplars. You should look for holes in the trunk, especially near the base and in exposed roots to determine if borers are the problem. Cankers, or running wounds, would indicate canker disease. Also look for evidence of warty-looking galls on the roots or trunk. This is another disease which could be causing the problem. If you find any of these symptoms take them to your local Cooperative Extension office for a recommended treatment, if one exists.

Another consideration is the fact that until last summer New Mexico had been suffering through several dry years. The younger, smaller, trees may not have exhibit problems because they are more vigorous with more vigorous root systems. If there has been damage to the root system of the older tree, it would have suffered more from the drought than the other trees. Besides, a tree like a person is less tolerant of environmental stress when it is older. Adequate watering during especially dry years will help alleviate environmental stress, but cannot totally compensate for the effects of age.

Consider whether or not this tree is becoming a hazard for property and health. If it is declining in health and is near the house, driveway, street, or area frequented by people, you should consider whether it would be safer to remove the tree rather than wait for ito fall and cause damage. The degree of decline and location are factors to consider. If you think it can remain for a few more years, you may wish to plant another tree nearby to become established and develop some size before the older tree must be removed.

Watermelon blossom end rot

My watermelon crop had at least a dozen blooms, and good sized melons but then died due to "brown rot" on the bottom of each melon (not the part that touches the ground, but the end of the fruit). The few that survived the rot, eventually "burst" and had to be removed. Our early growing season was extremely wet (over 12 inches in May!). uld this have caused these problems and what can we do to prevent the remaining melons from dying before they are fully mature? It doesn't seem to matter what age they get the "rot"...some are barely 2 inches in diameter, others are almost 6-8 inches before they turn brown. Can you help?

You have described the symptoms of blossom end rot. This malady can affect watermelons as well as cucumbers, tomatoes, chiles, squash, and many other fruits produced in the garden. As you have probably read, blossom end rot is due to a calcium deficiency in the developing fruit. The deficiency can be due to a lack of calcium in the soil, as is the case in parts of the country with acid soil. In the Southwest, with our alkaline soils and super abundance of calcium, it would seem that blossom end rot would be impossible. However, if water, which transports calcium and other minerals, doesn't reach the end of the fruit during the critical time when the fruit is developing, blossom end rot will develop. The failure of water to reach the fruit can be due to hot, dry, windy days which evaporate water before it reaches the fruit, or in your case due, perhaps due to waterlogged soil, which due to absence of adequate oxygen around the roots, prevents the absorption of water and minerals by the roots. So, yes, I believe the extremely wet conditions you experienced earlier, as the fruit were just forming is the cause of the problem. The solution is to avoid waterlogging of the soil, and maintaining both adequate water and oxygen in the soil around the roots. As the weather became drier, the problem should have resolved, if fungal or bacterial rots didn't infect the plants during the wet period.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

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