Expert Gardeners Say Plant Diseases Can Be Controlled With Preventative Measures

By Nancy K. Crevier

It is not just Connecticut residents who have been wilting in the humidity this summer. Calls to the UConn Home and Garden Education Center indicate that garden vegetables in the state are buckling under to leaf blights, powdery mildew, and molds, according to a recent press release. “New vegetable gardeners especially are concerned about leaf blights on tomatoes, powdery mildew on cucumbers, and gray molds on green beans,” said the release, issued last week.

“That kind of stuff is typical this time of year, and more so with the wet, humid weather we have been having this year,” said Jim Shortt of Shortt’s Organic Garden Center in Sandy Hook. “We have some fungus here and there, but there is not much you can do once it sets in,” said Mr Shortt. Fungicides can be applied every seven to ten days, but in order for them to be effective, he said, the weather has to be dry.

“The biggest problem we are seeing this year is that the tomatoes are just sitting there. We haven’t had enough consistent heat and warm nights for them to ripen properly. Last year was a good growing year with long, dry periods followed by a good rain, but not this year. So you will see a little more fungus-type problems,” Mr Shortt said.

As the owner of Cedar Hill Farm for more than 40 years, Frank Hufner has grown acres of vegetables over the years. He has downsized in recent years and now just staffs a booth at the weekly Bethel Farmers’ Market on Route 6, but still grows a good amount of produce. Lengthy spells of warm, humid weather create prime conditions for fungus and molds to grow, said Mr Hufner, but preventative measures can be taken to lessen the destruction caused by these diseases.

If gardeners start off with good, healthy plants, that is one of the more important steps that can be taken to avoid diseases. “Keep the plants healthy and well-fertilized, and make sure they are planted in good, full sun,” Mr Hufner suggested. A vegetable garden planted under a canopy of trees is bound to have problems he said. Plenty of air circulation around plants is also important, as is good soil drainage. One common mistake home gardeners make that can exacerbate fungus and mold problems, Mr Hufner said, is watering the whole plant instead of just the roots. Watering vegetables early in the day gives the plant time to dry out, as well, he recommended.

Through good garden management, this year Mr Hufner has experienced only a mild problem with downy mildew on his cucumber plants.

 “Once a fungus or mold is there, it is hard to eradicate. When we have these [humid weather] conditions, it might be wise to preventatively spray tomatoes and peppers, especially, with a fungicide,” said Mr Hufner. He prefers, however, to use pesticides and fungicides as a last resort. “We try not to spray repeatedly and really pay close attention to when we spray and harvest time. We watch that real close and are not even marginal,” he stressed.

The master gardener program coordinator at the UConn Agricultural Extension Service in Bethel, Sandy Wilson, has not fielded an unusual number of calls concerning vegetable plant diseases. “We have not had a huge amount of calls about fungus or mold problems,” said Ms Wilson. “We see more tree, shrub, and ornamental problems here, I think, than vegetable problems, but we have really not had any extremely crazy and out of the ordinary calls about wilt or vegetable molds,” she said.

New gardeners, however, may not be so aware of the importance of sanitation in a garden to keep fungal problems at bay, Ms Wilson added. “We do see tomato leaf wilt quite often, and new gardeners need to know to clean up those leaves at the end of the season and get rid of them. Leaves with wilt should be picked off so that the disease doesn’t spread,” she said. The same advice goes for rose plants, which are subject to black spot in this part of the country. “Pick off the affected leaves and clean up around the plants to control the spread of disease,” she advised.

The mold and fugal problems may be more of an upstate issue than for gardeners in Fairfield County, though, said Regina Campfield, the master gardener program coordinator at the Bartlett Arboretum in Stamford. “Upstate, there has been a different weather pattern this summer. They have gotten a lot more rain than we have here, so I think gardeners in the upstate area are seeing a little more problem with fungi and mold. I have to say, there is no unusual death and disease on our veggies here in Fairfield County,” said Ms Campfield.