Late Blight Confirmed on Tomatoes in Henderson County

This week Plant Pathologist Kelly Ivors found and confirmed late blight (by microscopic examination) in one small shaded area of a conventional tomato field in Henderson County. We have not been able to confirm its presence anywhere else in the tomato production areas of NC this summer, so I believe this is the start of the tomato late blight epidemic in WNC. We've had some rains recently and I'm sure it's out there elsewhere now, or soon to arrive.

Without proper preventative measures, late blight can completely defoliate and destroy a crop within one to two weeks. The disease can be severe on tomatoes grown in the mountains of North Carolina, as well as in late plantings in the Piedmont.

The first symptoms of late blight on tomato leaves are irregularly shaped, water-soaked lesions on lower leaves. During high humidity, white cottony growth may be visible on underside of the leaf. As the disease progresses, lesions enlarge causing leaves to brown, shrivel and die. Fruit lesions appear as dark, greasy spots that eventually turn a chocolate brown color, and can enlarge to the point of encompassing the entire fruit.

Refer to this website for more details on the symptoms of this disease. The application of fungicides plays a significant role in the control of late blight. Fungicides containing copper, chlorothanonil, or mancozeb are recommended for treatment in home gardens.

No fruit on your tomatoes?

We have had some seriously warm weather here in the past few weeks for WNC. Daytime temperatures above 90°F and night temperatures above 70°F result in reduced flowering and fruit set. There is considerable evidence that night temperature is the critical factor in setting tomato fruit, the optimal range being 59° to 68°F. With night temperatures much below or above this critical range, fruiting is reduced or absent. Low temperatures reduce the production and viability of pollen. High temperature, especially if accompanied by low humidity and moisture, hinders fruit set through failure in pollination and/or fertilization.

Apple Recipe Contest - September 3, 2010

The annual Apple Recipe Contest is only weeks away and NC Cooperative Extension is looking for both amateurs and professionals to enter their original non-copyrighted recipes. Winners will receive great prizes, a ribbon, and I can't forget to mention the bragging rights that accompany winning the contest at the NC Apple Festival. Recipe entry forms and the written recipe must be mailed, faxed, or delivered by September 1, 2010 to NC Cooperative Extension. If you would like more information, contact Renay at 828-697-4891.

Blossom-end rot on tomatoes

We have been receiving several calls lately concerning tomatoes that are rotting on the blossom end. The problem is blossom-end rot. Blossom-end rot is a fruit disorder that causes the blossom end of a tomato fruit to rot. The rot is dark brown in color and has a tough, leathery feel. It is usually worse on the first fruit cluster but can be a problem throughout the season.

Blossom-end rot is caused by a lack of calcium in the fruit. If the soil pH is too low, calcium is not available to the plant. Dry weather contributes to the problem.

You can also reduce blossom-end rot by spraying with a calcium chloride solution. Ideally, you should start spraying when the first green tomatoes are about the size of a silver dollar then spray once a week for three to four weeks.

Inconsistent watering encourages the problem of blossom-end rot. So, water as needed to maintain uniform soil moisture. Tomatoes need about 1 inch of water per week. During hot dry weather they may need more. Blossom-end rot tends to be worse on staked tomato plants and when high rates of nitrogen fertilizer have been applied.

While the tomatoes that are already affected will continue to be deformed, they are safe to eat. Simply cut out the bad portion and eat the rest.

For more information see: http://www.ces.ncsu.edu/depts/hort/hil/hil-28-d.html

Photo credit: Darrell Blackwelder

Fresh Market Tomato and Vegetable Field Day - August 19th Noon-4:30pm

Mark your calendars now and reserve the date for the annual tomato field day at the Mills River (formerly Fletcher) Research Station! This is your opportunity to see new up and coming varieties and learn the latest about disease, insect, and weed control for staked tomato production and vegetables in western North Carolina. As always, the afternoon field day will be followed by a pig pickin' at Lake Julian.

Tomato field day is sponsored by North Carolina State University, College of Agriculture and Life Sciences, NC Agricultural Research Service and NC Cooperative Extension Service, the North Carolina Department of Agriculture and Consumer Services, and the North Carolina Tomato Growers Association. For more information, contact Denny Thompson at 828.684.7197 or Jim Walgenbach at 828.684.3562.

Be Careful in the Heat!

The combination of heat, humidity and physical labor can lead to fatalities. The two most serious forms of heat related illnesses are heat exhaustion (primarily from dehydration) and heat stroke, which could be fatal. Signs of heat exhaustion or heat stroke need immediate attention. Recognizing those warning signs and taking quick action can make a difference in preventing serious injury or a fatality.

Follow these guidelines to insure a safe and pleasurable gardening season.

Sun

Sunlight contains ultraviolet (UV) radiation, which causes premature aging of the skin, wrinkles, cataracts, and skin cancer. There are no safe UV rays or safe suntans. Be especially careful in the sun if you burn easily or spend a lot of time outdoors.

Here’s how to block those harmful rays:

• Cover up. Wear loose-fitting, long-sleeved shirts and long pants.

• Use sunscreen with a sun protection factor (SPF) of at least 30. Be sure to follow application

directions on the bottle or tube.

• Wear a hat. A wide brim hat, not a baseball cap, works best because it protects the neck, ears, eyes, forehead, nose, and scalp.

• Wear UV-absorbent sunglasses (eye protection). Sunglasses don’t have to be expensive, but they should block 99 to 100 percent of UVA and UVB radiation. Before you buy sunglasses, read the product tag or label.

• Limit exposure. UV rays are most intense between 10 a.m. and 4 p.m.

Heat

The combination of heat and humidity can be a serious health threat during the summer months. If you work outside you may be at increased risk for heat related illness. So, take precautions.

Here’s how:

• Drink small amounts of water frequently.

• Wear light-colored, loose-fitting, breathable

clothing—cotton is good.

• Take frequent short breaks in cool shade.

• Eat smaller meals before work activity.

• Avoid caffeine and alcohol or large

amounts of sugar.

• Work in the shade.

• Find out from your health care provider if

your medications and heat don’t mix.

Herbicide Injury Showing Up in Henderson County

I have had multiple samples of herbicide injury on fruits and vegetables come in the office the past few weeks. Keep in mind that tomatoes are SO sensitive to some broadleaf herbicides that you can just walk past the plants with a sprayer on a hot day and they can get enough fumes to affect them. Above is a picture of what the injury can look like on tomatoes. Leaves tend to be stringy and malformed. Be sure to keep herbicides away from your fruits and vegetables.