GARDEN DETECTIVE: Late blight and downy mildew?

Q: I was wondering if you had any comments about the prospects of the tomato blight devastating our crops this year like it did last year. Would it be helpful to plant the tomatoes in the greenhouse? I do think the tomatoes I had in the greenhouse last year held up better than those outside, but it was my first year with the greenhouse, so I don't have a lot of experience. And what should we be looking for with the basil problems you thought we might have this year? --  Charles Bebber, Mount Sinai

A: I'm not too worried about a recurrence of late blight on tomatoes this year, as the pathogen does not typically overwinter in soil or dead plant tissue. Your greenhouse-grown tomatoes fared better because their exposure to the airborne spores was lower than for those that were out there in the garden, unprotected.

The disease often surfaces late in the season and mostly affects farms. Last year's devastation was due to the unprecedented early spring introduction of the pathogen, and its presence on plants sold to home gardeners not trained to recognize it. It can always resurface, but conditions have to be right to cause the problems it did last year - namely the pathogen has to be introduced, and we have to have a very wet spring.

Potatoes are another story, however, because the pathogen can survive in living plant tissue. If you left any tubers in the garden over the winter, dig them up, bag them tightly and discard them right away. Meg McGrath, a plant pathologist with Cornell University, is concerned that as plants sprout from potato tubers left over from last year, they may develop late blight and spur another epidemic in the Northeast. If you composted any infected (or even possibly infected) potatoes last year, better to discard the compost than take a chance.

Downy mildew of basil, is likely to be a problem, as it was discovered in the Northeast in 2008 and is expected to recur routinely here as it does in Europe. It turns the leaves yellow, which could easily be mistaken for a problem with nutrients or watering.

The pathogen can be transmitted from infected seeds, on leaves or, like late blight, via airborne spores. It also affects coleus, sage, salvia and mint - all members of the Lamiaceae family. Fungicides aren't really practical for home growers; just keep an eye out for symptoms: yellowing on the upper side of leaves, mildew underneath. And never eat infected leaves. Just toss them in the trash.

Q: I've had a ponytail palm, which is 62 inches tall in a 42-inch round pot, for 47 years. Before that, it belonged to my mother, and I had always admired it. She gave it to me when I moved into my house. I think it is rather exotic. I tried feeding it, but the leaves turned yellow (my mother never fed it, and it always looked healthy). Am I treating this plant properly? Is it worth money? I am 92, and none of my children want it. So if it was worth a lot of money and someone was willing to buy it, I probably would consider selling it. -- Jody Pollina, Commack

A: Ponytail palms (Beaucarnea recurvata), also known as bottle palms or elephant foot trees, are easy-care desert plants from Mexico. Actually they're not palms at all, but members of the agave family.

Since you've been caring for your plant for 47 years and it has survived nicely, I'm fairly certain you don't need any advice from me. As you surely already know, ponytail palms require bright conditions, but not much water. Allow the soil to dry out between waterings, then water deeply, but infrequently. And never allow water to collect in the bottom of the saucer or pot.

Ponytails don't take kindly to pruning, so don't be tempted to try to control its size. I would only apply fertilizer once a month over the summer, during its active growing phase.

I found 9-year-old, 20-inch-tall ponytail palms for sale at The Home Depot for $59.99, including Humiditray. I suppose, like anything else, worth would be dictated by the price someone is willing to pay.