CooperativeExtension ServiceMarshall County

1933 Mayfield Hwy.Benton, KY 42025

(270) 527-3285Fax: (270) 527-1555

http://marshall.ca.uky.edu

The April/May 2016 Edition of

Nikki’s NewsMarshall County’s Agriculture and Natural Resources Update

In this Issue:

Corn Replantp. 2, 4-5

Hydrangeas p. 3

Tomato Diseases

p. 6-7

GreenhouseRenovation S. Marshall Elementary

p. 8-9

Farm to Table Recipe

p.10

Farmers Market

Anyone with interest in becoming a vendor at a Marshall County Farmers Market can call the MC Extension Office to be added to the

potential vendor list. This is a no commitment list that will simply indicate the number of

people willing to participate in farmers market and then potentially lead to information

distribution on local farmers market vending opportunities. We are looking for anyone who produces fresh local produce or value added products. Examples: local fruits, vegetables,

meats, eggs, honey, jams, jellies, etc. (No flea market items please)

Call the MC Extension office at 270-527-3285

Crop NewsCorn Replanting Disease Risks

Chad Lee, Extension AgronomistReplanting and delayed planting of corn puts the crop at higher risks for certain diseases. The following is updated excerpt from AGR-195 Replanting Options for Corn. Delayed planting or late replanting, could result in increased outbreaks of several diseases.The “virus complex”: Infections of Maize dwarf mosaic virus and Maize chlorotic dwarf virus, viruses which survive in johnsongrass rhizomes and are spread (vectored) by aphids and leafhoppers, respectively, cause the virus complex. Compared to corn planted on time, late-planted corn is at an earlier stage of crop development during periods of peak vector activity, and earlier growth stage infection usually results in more severe disease symptoms.

Fungal diseases of foliage: Several leaf diseases, especially gray leaf spot, may be more severe when corn is planted late. This risk is especially high for fields in continuous no-till corn. Late-planted crops will be at a comparatively earlier stage of development during periods of high spore activity if weather is conducive for these diseases. Leaf infection early in plant development will reduce yields by decreasing photosynthetic capability and will increase susceptibility to stalk rots.

Fungal ear rots: Growers who plant full-season hybrids for grain production (120-day relative maturity, or greater) after June 1 increase the risk of fungal ear rots, because ears may not have sufficient time to dry adequately before harvest. (Note: Planting 120-day hybrids after June 1 is not recommended in Kentucky.) Planting shorter-season hybrids after June 1 helps assure maturity before frost and lower grain moisture contents at harvest. In addition, fall armyworm can be more severe on late-planted corn. Ear feeding by this insect can increase the incidence of ear rot diseases by providing wounds allowing fungal invasion.

Fungal stalk rots: Increased stalk rot diseases could result from delayed planting. The shorter daylength and drier weather late in the season both may favor stalk rots, as these can result in decreased carbohydrate levels in the stalk and more plant stress, which can favor infection.

Growers who still want to plant corn late should use hybrids with resistance to these diseases. Disease resistance is not as common in mid-season and short-season hybrids as in full-season hybrids. Therefore, growers are advised to be sure mid- and short-season hybrids have resistance to the above diseases, particularly since these could become more severe than normal.

Figure 1: Gray Leaf Spot

Flower NewsGrowing Hydrangeas in Kentucky

By Michael Boice and Lauren StatePrimarily known as a source of summer color flowering June through August long after most shrubs have finished. Hydrangeas’ interesting bark and flower heads can also provide winter texture when left untrimmed until spring. Four species are commonly used in Kentucky.

Big Leaf Hydrangea is the most widely used hydrangea species. Its large flowers range from white to pink to blue. While white cultivars remain white, pink or blue cultivar color is determined by soil pH and availability of aluminum. A soil pH range between 5.0 to 5.5 will generally produce the blue flowers, and a pH of 6 and above inspires pink flowers. Most cultivars of this species bloom on the previous season’s wood. If temperatures drop too low, the flowers for the next season will be lost. New selections like “Endless Summer” bloom on current season’s growth, providing blooms even if flower buds are killed by late spring frosts.

Smooth Hydrangea is popular for its large, white blooms from June to September every year on new growth. Removing the flowers as they turn brown will encourage a second flush of flowers in August. Part shade is best in locations where the weather is generally hot and dry. This hydrangea grows three to five feet tall, making it a possible choice in smaller landscape spaces. There are several good cultivar selections, but the most popular is “Annabelle.”

Panicle Hydrangea is one of the larger shrubs growing six to ten feet tall and six to ten feet wide depending on the cultivar. This plant will grow best in full sun. Enjoy the white to purplish-pink flowers from June to September. Blooms can be pruned when they turn brown or during the winter. One popular selection of this species is “Limelight” with large, light green flowers that mature to white.

Oak Leaf Hydrangea, native to the southeastern United States, is known for its large, oak leaf-shaped foliage, and is a popular landscape choice for areas with part shade. The white to purplish-pink flowers are four to twelve inches long with three- to four-inch wide panicles. The flowers are abundant and fragrant. In the fall, the foliage turns to shades of red, orange-brown, and purple, adding additional color to the landscape.

Hydrangea tip: A lot of plants struggle when the ground is not properly fertilized, but a lot of gardeners over fertilize the ground where they plant their hydrangea flowers in an attempt to change the color of the flower. Some of the more common fertilizers that are used have a high concentration of nitrogen in them, and nitrogen is a great way to boost the growth of your plant, but it will put all of its energy into creating foliage instead of flowers.

More Crop NewsCorn Replanting Herbicide

Replant RestrictionsChad Lee, Extension Agronomist

As farmers consider replanting corn, the herbicides already applied may limit the options for replant. The following table is an updated version of the table 8 in AGR-195 Replanting Options for Corn. The table below lists corn herbicides and the potential risk associated with replanting corn, grain sorghum or soybean. This table is not exhaustive, and the herbicide label should be consulted for more details on crop rotation limitations.

Table 1. Risk to crops replanted following use of corn herbicides. (This table is a guideline. Consult the herbicide label for additional details. This table is adapted from AGR-6 2016 Weed Control Recommendations for Kentucky Grain Crops)

Continued:

Horticulture NewsVegetable Diseases to Scout for: Kim Leonberger, Ext. Associate & Emily Pfeufer, Ext. Plant Pathologist

Kentucky vegetable growers should be on the lookout for early blight and Septoria leaf spot of tomato. As the most common diseases of tomato in Kentucky, homeowners or growers not on a preventative spray program always have at least some Septoria leaf spot and early blight pressure. Both diseases commonly occur in fields under wet, humid conditions. They may also occur in greenhouses or high tunnels, particularly near side walls or when plants are grown in natural soil without plastic mulch. Prevention, early identification, and management will help reduce plant losses. Here are the symptoms to look for, preventative tactics, and brief suggestions on how to treat crops once disease is confirmed.

Early Blight: Early blight is caused by the fungal pathogens Alternaria solani and A. tomatephila. These pathogens overwinter in plant debris from the previous season. Spores are initially splashed onto the lowest leaves, where symptoms are first apparent, but frequent rain or overhead watering can spread spores throughout the plant. Leaves, stems, and fruit may become infected at any stage during the growing season, which can result in fruit or plant loss. Early blight is favored by moderate temperatures, high humidity, and frequent rainfall. Once established the disease can spread rapidly in dense plantings. Potatoes are also susceptible to early blight, and symptoms, preventative tactics, and management are similar to tomato.

Symptoms: Dark-brown lesions with a concentric ring pattern develop on leaves or stems, sometimes with a chlorotic (yellow) halo around the lesion (Figure 1). Older leaves are usually affected first, with the disease spreading up the plant to affect newer growth. Lesions enlarge and may coalesce to result in blight (rapid death). Affected fruit develop dark-brown lesions with a concentric ring pattern, typically at the attachment end (Figure 2).

Figure 1: Early blight results in the development of dark-brown lesions with concentric rings or bulls-eye patterns. (Photo: Kim Leonberger, UK)

Figure 2: Fruit affected by early blight develop dark-brown lesions with concentric rings (Photo: Yuan-Min Shen, Taichung District Agricultural Research and Extension Station)

Continued:Septoria Leaf Spot: This is caused by the fungal pathogen Septoria lycopersici. The pathogen overwinters in plant debris from the previous season. Spores are initially splashed onto the lowest leaves, but frequent rain and overhead watering will spread the disease throughout the plant. Only leaves, stems, or petioles may become infected, which can result in significantly reduced plant vigor. Septoria leaf spot is favored by moderate temperatures, high humidity, and rainfall. Once established the disease can spread rapidly in dense plantings of tomatoes.

Symptoms: Small circular lesions with darkened borders and tan-brown centers are characteristic of this disease (Figure 3). The number of spots increases as disease severity increases. Blighting (rapid death) may occur in severe cases, which may kill plants while leaving a few unblemished fruit. The fungus produces additional spores in pycnidia, which are small, black specks seen in the centers of older lesions.

Early Blight & Septoria Leaf Spot ManagementCultural Practices: Select varieties with resistance or tolerance to early blight and/or Septoria leaf spot. Do not set transplants with visible leaf spots. Remove plant debris or weeds from the growing area. Remove and destroy heavily infected leaves from indeterminate tomatoes. Use drip irrigation (instead of overhead watering) to reduce leaf wetness. Improve greenhouse ventilation to reduce humidity. Use recommended plant spacing to facilitate air movement and leaf drying. Practice crop rotation. Chemical Approaches: Start plants on a preventative fungicide program within 2 (field) or 3 (greenhouse) weeks of setting plants.

Greenhouses: Apply mancozeb and/or copper on a 7 to 10 day schedule early in the season. If moderate disease pressure continues as harvest approaches, replace mancozeb with a systemic fungicide; otherwise continue with copper every 7 to 10 days. For specific systemic fungicide options with shorter preharvest intervals, see ID-36, page 18.

Fields: Apply mancozeb or chlorothalonil on a 7 to 10 schedule early in the season; incorpo-rate copper for bacterial disease management. Shorten spray intervals under rainy conditions. Use a systemic fungicide tank-mixed with a protectant (mancozeb, chlorothalonil) at the third spray, and alternate between protectants and systemic fungicides as the season continues. A sample fungicide program for tomatoes may be found on page 97 in ID-36.

As always, all label recommendations must be followed when applying fungicides to crops. Pay particularly close attention to pre-harvest intervals.

Figure 3. Photo: Kenny Seebold, UK

MC Extension News Greenhouse Renovation at

South ElementaryThis spring semester, the 1st graders at South Marshall Elementary School studied the importance of agriculture and how to grow healthy foods. The MC Health Department partnered with the Marshall County Extension Office to pursue a grant to renovate the

greenhouse and garden. We received a 5-2-1-0 grant for $500 to renovate the greenhouse. 5-2-1-0 stands for: 5 or more fruits and vegetables, 2 hours or less screen time, 1 hour or more hours of physical activity, and 0 sugary drinks. This program was designed to teach students how to prevent obesity.

After receiving the grant, a group of volunteers joined together to renovate the greenhouse and garden. Master Gardeners: Dennis Riley, Charles Frazier, and future MG Joe Mitchell, along with Lori Henry from the MCHD and Nikki Bell the MC ANR Agent renovated the greenhouse and raised beds. (Before and after pictures can be seen on the following page.)Meanwhile, the 1 st graders worked on how they were going to teach the community to grow their own fruits and vegetables. After many brainstorming sessions and trying to grow their own vegetables with little luck, the students decided to call in a “specialist.” Nikki critiqued their project and presented a lesson on what it takes to grow vegetables.

After learning how to grow vegetables, it was time to put the newly renovated garden and greenhouse to use. With the help of the volunteers listed above, plus MG’s Bob and Jeanne Gooud, the 1st grade successfully grew tomatoes and pepper plants to take home at the end of the school year, broccoli, cabbage and enough lettuce to feed the whole school salads.

Left: Charles Frazier helping the students plant peppers. Middle: Bob Gooud teaching students how to transplant vegetables Right: Students setup a salad stand and fed fresh salads to the school

Before After

The Planting Crew!

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Farm To Table Recipe