Wednesday, August 27, 2008

Water, water everywhere!

We finally received some rain and boy did we need it! But, of course when it rains it pours. Below are 3 issues that cause concern with excessive rainfall.

1. Equipment. Please make sure that if there is heavy rain that equipment gets moved to a place where it cannot be damaged. I know a few growers who took the time to move their irrigation pumps further up the banks to accommodate the flowing rivers and creeks and I hope that everyone was able to do this in a timely fashion.

2. Flooding. With large amounts of rain flooding of fields from river, creek or stream water is a major concern. I am sure that you all remember Hurricanes Frances and Ivan! Because there is no way of knowing what kinds of contaminants are found in flood waters, crops that have been flooded CANNOT be harvested and sold for human consumption. A chlorine rinse is NOT adequate to guarantee safety of the produce. Crops intended for human consumption are considered contaminated if they have been covered with flood waters from rivers, creeks or streams. Growers should distinguish between rainwater that accumulates on a field because of excessive rainfall versus fields covered by flood waters from risen rivers, creeks or streams.
Here is a link from the Food Science Dept. at NCSU:
If you would like more information about food safety of flooded crops or have any questions please contact me and I will do my best to provide you with assistance.

3. Disease. Be on the look out for diseases that are favored by cool and wet conditions such as Late Blight of tomato and potato, Phytophthora Blight or root rot and Downy Mildew of cucurbits. If you think you have a disease problem make sure to get it positively identified so that we can get you on an appropriate spray program (if necessary or applicable). There have been no reports of Late Blight, yet, but Downy Mildew of cucurbits has been reported on cucumber in the WNC.

*Thanks to Dr. Jeanine Davis and Diane Ducharme for passing along great information about food safety issues in flooded fields.

Tuesday, August 5, 2008

Early Blight of Tomatoes

One of the first disease problems I have encountered in WNC is Early Blight on tomatoes. Early blight is caused by Alternaria solani, a fungal pathogen. Traditionally, symptoms of Early Blight appear as spots on the foliage. These spots have concentric circles and look like a "bull's eye" (image, right- click on image to enlarge). These symptoms first appear on older leaves of the tomato plant.

In addition, Early Blight can actually affect the stems of the tomato plants (image, below). This condition is known as "collar rot". Notice that the stem lesion begins where the plastic begins, not at the soil line. Concentric circles may also be seen in the stem lesions. Early Blight attacking stems can be an severe problem, especially in fields that are not fumigated, as plants will not be able to survive stem girdling.

In order to control A. solani and other important pathogens of tomato, prevention is key. Dr. Kelly Ivors and Dr. Frank Louws, both of the Department of Plant Pathology at NCSU have put together a comprehensive Foliar Fungicide Spray Guide for Tomatoes in NC. This is program is a holistic approach to tomato disease control and followed by many WNC tomato growers.

Other fungicides that are very effective for Early Blight on tomato are the strobilurin fungicides, azoxystrobin (Amistar, Quadris) and pyraclostrobin (Cabrio). *Strobilurin fungicides must be rotated with a fungicide that is not in FRAC group 11.* Other fungicides with good efficacy towards Early Blight are boscalid (Endura), mancozeb (Dithane, Manzate, Penncozeb, Manex II) and maneb (Manex, Maneb).
Efficacy data obtained from Southeastern Vegetable Extension Workers 2008 Vegetable Crop Handbook. Always follow application guidelines on the fungicide label!

Monday, August 4, 2008

Welcome to the WNC Vegetable and Small Fruit Blog

My name is Sue Colucci and I am the new Area Specialized Agriculture Agent in Henderson, Haywood and Buncombe Counties in Western North Carolina (WNC) with responsibilities in vegetables and small fruits.
I joined the NC Cooperative Extension Service on July 15 after finishing my master's degree in Plant Pathology at NC State in Raleigh. My project involved cucurbit downy mildew (caused by Pseudoperonospora cubensis), a common problem in NC on squash and pumpkin and a re-emerging disease problem on cucumber.
If there is anything that you would like more information about, please contact me and I will do my best to answer your questions or find pertinent information for you.
I am looking forward to working with the vegetable and small fruit growers here in beautiful WNC and blogging about the problems and questions that I am faced with.