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basil

Pest Alert: Basil Downy Mildew Found in Western North Carolina – July 22, 2019

July 29, 2019

Basil downy mildew has been confirmed on the variety ‘Genovese’ in the NC State University research plots in Haywood County, North Carolina.

Basil Downy Mildew Spores on Underside of Leaf
Basil Downy Mildew

Basil downy mildew characteristics

  • Pathogen: Basil downy mildew is caused by the fungus-like oomycete pathogen Peronospora belbahrii.
  • Host crop: Basil (Ocimum basilicum)
  • Host parts affected: Leaves are severely affected, which can result in yield reduction or plant death.

 Identification

The disease typically begins in June and lasts throughout the growing season. Symptoms include yellowing or browning of leaves, which may be mistaken for nutritional problems. Infected leaves have many dark spores on the underside of infected leaves that can be seen without a microscope or hand lens.

  • High-humidity and moisture—6 to 12 hours of moisture from morning dew, rain, or overhead irrigation.
  • Cool temperatures (60°F).

Prevention

The disease has not been found on the resistant sweet basil varieties ‘Thunderstruck,’ ‘Devotion,’ ‘Passion,’ and ‘Obsession.’ Planting these resistant varieties or pathogen-free seed of other varieties is essential to prevent basil downy mildew.

Some basil types are less susceptible than sweet basil varieties. Researchers have found red basil (‘Red Leaf’ and ‘Red Rubin’), Thai basil (‘Queenette’), lemon basil (‘Lemon,’ ‘Lemon Mrs. Burns,’ ‘Sweet Dani Lemon Basil’), lime basil (‘Lime’), and spice basil (‘Spice,’ ‘Blue Spice,’ ‘Blue Spice Fil,’ ‘Cinnamon’) to have less severe downy mildew symptoms.

In addition to infected seed. disease also spreads from airborne spores of Peronospora belbahrii. Help control by watering early in the mornings, so foliage dries quickly, and allowing enough space between plants to increase air circulation.

Disease control for home gardeners

Be diligent in checking basil leaves for downy mildew. Fungicides are most effective when applied in a preventive, weekly spray program. Products containing the active ingredients copper or chlorothalonil (‘Daconil’ is the trade name of one product with chlorothalonil) are the only effective products available to home gardeners. Apply to achieve good coverage on both sides of the foliage and apply the products before disease begins.

 For more information:

Pest Alert: https://plantpathology.ces.ncsu.edu/2019/07/basil-downy-mildew-found-in-western-north-carolina-july-22-2019/

Basil Downy Mildew: https://content.ces.ncsu.edu/basil-downy-mildew

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Categories Plant Diseases Tags basil, diseases, downy mildew, pest control, Symptoms

Growing Herbs: For Your Kitchen!

May 1, 2019

If you’re planning a kitchen herb garden, think about what herbs you like to use. Are you interested in drying herbs for tea—like mint or lemon verbena?  Do you cook Italian food (basil, oregano), Mexican food (cilantro), or Asian recipes (Thai basil, lemon grass)?

What is an herb?

Merriam Webster defines an herb as a plant or plant part valued for its medicinal, savory, or aromatic qualities. Here we’re talking about the savory or culinary herbs that you can grow in your home garden. Herbs are generally easy to grow, requiring only plenty of sunshine and well-drained soil. Many are suitable for planting in containers on a deck or patio. Herbs may be annual, perennial, or even biennial (parsley).

Herb Garden in Container_by Frances Carter_CC_Flickr
Herb garden planted in container

Where to grow herbs

What kind of space can you devote to an herb garden—a few pots on a balcony, a small raised bed, or a section of a large vegetable garden? Check out the size and space needs of the herbs you would like to grow. Note: Some herbs—such as mints and lemon balm—need to be contained if you don’t want them to take over your space!

Herb Garden in Raised Beds_by Kyla Kae_CC_Flickr
Herb garden planted in raised bed

Place herbs in average garden soil (or potting soil if you are using containers) where they will get at least six hours of sun a day. While annual herbs generally need more water than the perennials—which tend to be from the sunny, drier Mediterranean region—all need good drainage. Fertilize only lightly for best flavor and aroma. Grown with enough sun and good air circulation, most herbs are pest and disease free.

How to get started

When you choose seeds or plants, look at the planting times and hardiness zones to determine when to plant and if the varieties you choose will thrive in your location.

 Seeds. You can purchase seeds for almost any culinary herb, and some herbs are better planted from seed directly into the garden, such as dill, cilantro, and fennel. Dill and cilantro are both short-lived and usually require plantings every few weeks if you want a continued supply.

Plants. Most perennial herbs, such as mints, oregano, rosemary, thyme, and tarragon, are easier to establish from plants—to ensure you get the correct varieties as well as to have plants large enough to harvest in their first season.

 How to harvest

Growing your own herbs means you’ll have fresh herbs to use in season. Once your plants are established, you can start harvesting—just don’t remove more than ¾ of the leaves at once! Pick your herbs early in the day. For annual herbs, harvest before the plants start to flower. Some annual herbs will last until frost. Some perennial herbs may even stay green into winter for occasional harvest! To preserve herbs, they may be dried or for best flavor, frozen. Freeze chopped herbs in a little water in ice cube trays.

Traditional hanging method for drying and preserving herbs.
Herbs of sage, garlic chives, and parsley hang ready for drying.

The Buncombe County Extension Master Gardeners’ will be staffing an information table at the Asheville Spring Herb Festival at the WNC Farmers Market on May 3, 4, and 5, 2019. 

 Article by Joyce Weinberg, Extension Master GardenerSM Volunteer

For more information:

Growing herbs:

https://content.ces.ncsu.edu/growing-herbs-for-the-home-gardener

Harvesting and preserving herbs:

https://content.ces.ncsu.edu/extension-gardener-handbook/16-vegetable-gardening#harvestingherbs

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Categories General Gardening Tags basil, cilantro, Dill, fennel, herbs, mint, oregano

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