Benton County Cooperative Extension Service

1204 SW 14th Street, Suite 2, Bentonville, AR 72712 • Tel: (479) 271-1060 • Fax: (479) 271-5713 • www.uaex.edu

Managing Strawberry Diseases Let’s hope the 2016 season is better for strawberry production than the wet 2015 season of last year. Strawberries are susceptible to several different diseases that damage the plant and reduce or destroy fruit. These are two of the most common ones:

Botrytis/Gray Mold This fungus enters through the bloom and is spread by rainfall. If leaves are wet for 6 or more hours

and air temperature is 60-70 degrees F, botrytis can develop quickly. This disease has developed resistance to fungicides in FRAC Code 11 (Pristine, Cabrio, Flint, Quadris); therefore these products are ineffective. The current recommendation is to use Captan as your primary fungicide. University of Florida research shows Switch is also effective against botrytis and may be applied with Captan if infection is likely.

Anthracnose Strawberry Anthracnose is similar to botrytis in that it is fungal and disease development is favored by wet foliage or fruit (12+ hours) and

moderate temperatures (68-70 F). When conditions are favorable, varieties with little or no resistance to anthracnose are often a total loss. Avoid harvesting

in a wet field if possible as spores are only spread by splashing water (not wind). Drip irrigation and raising berries in high tunnels are the best tools for susceptible varieties. As with botrytis, Captan is the recommended fungicide for fruit infections and may be applied on a 7-10 day rotation with susceptible varieties (Treasure, Camerosa, Festival). Abound, Cabrio have proved ineffective on some farms due to resistance, leaving captan as the only choice in this case. Anthracnose also causes lesions on runners and leaf petioles, and a different species causes crown rot, which are managed differently than fruit infections.

Tips on Irrigating Strawberries Maintaining adequate soil moisture is a must before and during the strawberry season. If we don’t get rain, we have to turn on the water. Consider the following if planning or working on your irrigation system: Maintain around 12 pounds pressure in tape Use a regulator in each field, or in zones managed differently Aim for 35 gallons water per 100 row feet; 0.4

or 0.5 GPH tape should work If fertigating: determine how long it takes to

fully charge irrigation system and to get soil wet. Inject fertilizers toward the end of that time.

Flush fertilizer from lines when finished to prevent salts from crystallizing and plugging holes. It’s time to begin leaf/petiole sampling to plan fertilization. Call the office if you are interested in assistance collecting and submitting samples.

University of Arkansas, United States Department of Agriculture and County Governments Cooperating. The Arkansas Cooperative Extension Service offers its programs to all eligible persons re-

gardless of race, color, sex, gender identity, sexual orientation, national origin, religion, age, disability, marital or veteran status, genetic information, or any other legally protected status, and is an

Affirmative Action/Equal Opportunity Employer.

Commercial Horticulture Newsletter March/April 2016

Maximizing Your Market Display Your goal at the farmers market is to sell all the produce you haul to town. Use color, a variety of products, even attractive signage to draw customers to your booth. Remember that some customers are unfamiliar with the natural variability in crop appearance, and may have an idea in their mind of what a specific crop should look like. Variation from the “norm” in color and form may leave patrons wondering if they want to take a chance on a veggie with which they are unfamiliar. If you are selling an heirloom variety for example that looks different, educate customers as to its qualities. Create signs or information sheets to educate customers about unique qualities or perhaps a variety of historical value. Distribute tested recipes, or perhaps a “veggie dish kit”, so that patrons leave your booth with all the raw ingredients and recipe needed to prepare the dish. Otherwise: Only display fruit of highest quality (correct

size, minimal or no blemishes ) Pick as close to market time as possible to ensure freshness. Crops held until sale in cold, moist conditions

(32-36 F; 90-95% relative humidity) include: asparagus, brassica crops, greens, carrots and parsnips

Crops held until sale in cool, moist conditions (40-50 F; 90-95% relative humidity) include: snap beans, cantaloupe, watermelon, cucumber, peppers, ripe tomatoes, potatoes

Many customers may not know Arkansas Black was bred in Benton County around the turn of the last century. Market this as a local, high-quality apple.

Cole Crop Management This includes broccoli, cauliflower, brussels sprouts, cabbage. Plant and row spacing

depend on the crop, but 3 feet between rows and 12 to 18 inches between plants are pretty close for all. If soils are heavy (clay), use raised beds 6 to 8 inches deep. Cole crops prefer a soil pH of 6.0 to 6.5, so apply lime right away if soil test results indicate the need. These crops are fairly heavy nitrogen feeders, and all fertilizer applications should be made according to soil test recommendations. However here are some generalities: Nitrogen: 120 lbs N/acre if soil organic matter is

less than 3%. 80 lbs N/acre if soil OM is greater than 3%

Phosphorus: 25 to 200 pounds P2O5 per acre. If your field has received poultry litter in the past phosphorus levels may be fine, but soil tests tell the story.

Potassium: up to 250 lbs K2O/acre, again based on soil test results.

Boron: Provides response in growth on low or-ganic matter soils. Household borax (11% B) can be broadcast across the field as a fertilizer, but be careful not to over apply as Boron is toxic at high levels.

Give transplants a heavy feeding just before set-ting in the field, or feed each transplant with a starter fertilizer solution to give it a boost.

Plan to sidedress with 60 pound N/acre when rapid growth begins (2-3 weeks after transplant). Don’t overdo it with N on broccoli or it may grow too fast and form a hollow flower stalk.

Save the Date April 1: Spring Turn Out-Tune Up, 2:00 to 6:00 pm, Benton County Fairgrounds. Pasture and livestock management meeting. Dinner provided. April 1: Farmers Market Promotion Grant, postmark date. Application available at aad.arkansas.gov April 5: Private Applicator Training, 6:30 pm start time, Benton County Extension Office. Training to receive restricted use pesticide license. April 21: Chainsaw Safety Workshop, Gentry Fire Station. Contact Gail to RSVP @ 273-2622, ext. 109

Is Your Flower Crop Hungry? It is easy to overlook the importance of fertilizing flower crops since they don’t feed as heavily as most fruits and vegetables. However to achieve good growth and a healthy, showy plant, fertility must be managed well. The following deficiency symptoms come courtesy of Jared Barnes, North Carolina State University. Remember, these symptom descriptions are guidelines. Plant tissue testing is the only way to know the status of nutrient content. We can also code soil tests for flower crops.

Symptoms of Macronutrient Deficiencies Nitrogen Deficiency – Initial: lower leaf yellowing, discoloration

(purple, etc.), smaller plants Advanced: plant yellowing, lower leaf necrosis Phosphorus Deficiency – Initial: smaller plants, lower leaf purpling,

darker leaves (hard to see without healthy plant comparison)

Advanced: lower leaf necrosis, leaf drop Potassium Deficiency – Initial: necrotic spots on lower leaves, lack

of stem elongation, upper leaves appear healthy

Advanced: necrotic spots increase in size, failure to flower

Calcium Deficiency – Initial: middle and upper leaf necrotic spots,

reduced root growth Advanced: necrotic spots enlarge, entire

plant collapse, failure to flower, stem topple Magnesium Deficiency – Initial: marginal or interveinal yellowing Advanced: leaf bleaching, flower color

change, lower leaf necrosis and/or leaf drop Sulfur Deficiency – Initial: upper leaf yellowing, smaller plant

size Advanced: entire plant yellowing, red discoloration, lower leaf necrosis

Symptoms of Micronutrient Disorders Boron Deficiency – Initial: smaller plants, upper leaves distort

and become thick and/or brittle Advanced: lower leaf yellowing, failure to

flower Boron Toxicity – Initial: marginal browning on lower leaves Advanced: marginal browning on upper

leaves, leaf distortion, lower leaf necrosis Copper Deficiency – Initial: leaf bleaching or spotting Advanced: spot sizes increase Iron Deficiency – Initial: interveinal chlorosis or yellowing on

upper leaves Advanced: interveinal chlorosis or yellowing spreads to lower leaves Manganese Deficiency – Initial: yellowing (variable- marginal, whole

plant, lower leaf) Advanced: yellowing intensifies, necrosis on

upper leaves Zinc Deficiency – Initial: smaller plant size, some distortion of

flowers Advanced: leaf necrosis, interruption of

flowering

Left photo: chrysanthemum flower, boron deficiency Right photo: normal chrysanthemum flower

Calcium deficiency in tulip. Note the collapsed stem.

Cooperative Extension Service 2301 South University Avenue Little Rock, AR 72204-4940 OFFICIAL BUSINESS

Neal Mays County Extension Agent—Agriculture Benton County, Arkansas

How to Take A Good Quality Soil Sample

1. Determine field boundaries. Sample according to crop,

difference in soil or management.

2. Using a shovel or probe, take several subsamples to depth of root zone. For vegetables, 6-8 inches. Fruit crops, 10-12 inches.

3. Take several subsamples randomly from across field. More sub-samples = better results.

4. Combine all subsamples taken in the field. Remove a pint of the mixed soil and bring to Extension office. Soil must be air dry. Repeat for other fields.