Summer Tipping, Fruit Disorders and Irrigation. Amanda McWhirt Horticulture Production- Extension Specialist. Osage: June 8; June 26

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1 Summer Tipping, Fruit Disorders and Irrigation Amanda McWhirt Horticulture Production- Extension Specialist Lifecycle Jan Feb Mar April May June July Aug Sept Oct Nov Dec Photo Gina Fernandez Photo Gina Fernandez Natchez: June 5; June 17 Average Day of First Harvest and Peak Fruiting in Osage: June 8; June 26 Clarksville, AR Ouachita: June 12; June days from flower to ripe fruit Harvest period 4-7 weeks Heat issues over F Navaho: June 20; July 1 Apache: June 25; July 6 Photos: Amanda McWhirt 1

2 Blackberry Plant Structures Lateral Floricane Primocanes Source: NSW WeedWise. Floricane Cultivars, Spring/Summer: Tipping Floricane Primocane Soft Tipping Hard Tipping Primocanes: (for erect/semi-erect cvs) Tip primocanes in summer at high ( just above top wire) to force laterals which will bear fruiting clusters in year 2 Apply fungicides after tipping, particularly if rain is expected 2

3 Primocane Cultivars: Tipping and Pruning Spring/ Summer - Primocane tipping done when canes reach 25-30, before bud set - Option: Continue tipping laterals, double tipping Fruit Disorders 3

4 Red Cell Regression Red Cell Reversion Red Druplet Disorder or Red Cell Reversion of druplet color after harvest or cooling Is associated with rapid temperature changes in the environment or in the berry. Ways to prevent: Harvest before 10am, while berries are still cool from the night before Shade berries in the field as they are being harvested Limit physical damage at harvest Stepwise cooling (this is cooling the berries first to room temperature, than to the cooling room temperature) Avoid excess N applications at harvest Fruit is still edible White Druplet Individual or groups of druplets turning first white and then later brown in color. Is associated with a drop in humidity and an increase in temperature. Early in the season Apache is a variety that is more prone to this disorder. Sunscald is a related disoder 4

5 Poor Pollination Blackberry flowers are selffertile Bees are important for ensuring good pollination 2 colonies per acre Blackberry flowers have pistils must be fertilized to get a good sized and shaped berry. Viruses Double Blossom (Rosette) Caused by the fungus, Cercosporella rubi Thornless varieties are not susceptible to this disease Only effects floricanes Disease mimics the biennial lifecycle of the crop cycles through the flower to the primocanes at the time of pollen production in the flower. After infection primocanes will appear normal until their 2 nd year (floricane). Photos: Bryce Baldrige University of Arkansas, CES 5

6 Double Berry Primocane fruiting varieties Flower in the middle of summer High heat during flowering J. Clark- more double berry occurring on 'Prime- Ark Freedom' and 'Prime- Ark 45' than on 'Prime- Ark Traveler'. Fasciation Causes: Environmental factors Herbicide Disease Insect feeding Virus Other Generally it is isolated and is not contagious or prone to spread. 6

7 By weight berries are 85-95% water. Irrigation Blackberry Water Needs Bramble plants need about 1 to 2 inches rainfall per week This amount is especially critical during fruit formation and harvest. 1 acre inch= 27,156 gallons Salinity tolerances Water test at your local laboratory Above 1.5 ds/m yield decline may occur How long to run your irrigation system? Drip tape flow rate, row spacing Example: 1 gph emittors, emitters 12 apart, 10 row spacing = gallons per hour, or 6.25 hours to get 1 of water. Soil type 7

8 Effect of Texture on Soil Properties Sand Silt Clay Water Infiltration Rate Fast Medium Slow Water-holding capacity Low Medium High Plant-available water Low High Variable Nutrient-holding Capacity Low Medium High Factors Affecting Water Needs Water loss from plants is greatest on clear, hot windy days (may lose 0.25 inches per day) than on cool, overcast days. Plastic mulches reduce evaporation loss from the soil but also reduce the amount of rainwater that can reach the root zone for young plants. Tensiometers can be used to monitor soil moisture Place in the root zone Maintain between centibars 8

9 Example Drip Irrigation System Example Fertilizer Injector: Venturi Type Filter Nutrient Tank Nutrient Tank Filter Pressure Regulator Other Considerations 16mm hard tube with Button type emitters Emitters every 4, 1-2 gal per minute Drip tape Bury 3-4 Holes up Be aware of rodent damage to lines Sprinkler irrigation Frost protection 9

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