The Blueberry Bulletin, July 26, 2001
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The BLUEBERRY BULLETIN A Weekly Update to Growers Dr. Gary C. Pavlis, County Agricultural Agent 6260 Old Harding Highway, NJ 08330 Phone: 609/625-0056, Fax: 609/625-3646, Email: [email protected] July 26, 2001 Vol. XVII, No. 15 AT A GLANCE… BLUEBERRIES Insects: Dr. Sridhar Polavarapu, Extension Specialist in Blueberry Entomology, Rutgers University Mr. Dean Polk, IPM State Agent - Fruit Problem - Solution Anthracnose: Field counts have increased since last week. Anthracnose is present in 1 out of 5 samples. This Anthracnose - represents a 3 fold increase over the previous week. Captan 50 WP 5.0 lb/A Growers with late varieties should be aware of this Captan 80 WP 3.1 lb/A disease pressure when making fungicide choices. Captec 4L 2.5 qt/A Alternaria: Alternaria is present in one out of 7 Blueberry Maggot samples. The incidence of alternaria found in the field Yellow Sticky Traps has not shown much change since last week. Aphids Aphids: While aphid populations are present in about Provado 1.6F- 3to4 fl oz/A 44% of samples taken, populations exceed 10% of terminals infested in only 8% of those samples. While aphids are still present, they are secondary to blueberry maggot. Blueberry Maggot: Adults counts have increased over INTERNET ADDRESS the last week. In fact, while reviewing data from Click on to the RCE Web site previous years, counts in Atlantic County are higher than and see our 'Web Page'. during the previous 2 years for this time of the season. www.rce.rutgers.edu/pubs/blueberrybulletin Growers with late varieties should maintain maggot programs where flies are being captured. (See pest map for blueberry maggot on page 3.) Redbanded leafroller (RBLR): Small to medium sized larvae of RBLR are being seen at several Atlantic county locations. Larvae at this time tie up several berries together for shelter and feed on the surface of the berries. This feeding injury may also serve as the entry point for fruit rot fungi. Insecticide applications are (Continued on page 2.) recommended if more than 1% fruit clusters are Crop rooting depth and the soil water-holding damaged or if larval population exceeds more than one capacity are used together to determine the total water- larva per 100 fruit and leaf clusters. If insecticide holding capacity of the rooting volume. The capacity of applications are required, use Imidan or Lannate. ❦ the rooting volume is important in scheduling irrigation. Disease and Culture: Table 1. By Gary C. Pavlis, Ph.D. Typical Water-holding capacity for various soils. Atlantic County Agricultural Agent Texture Water-Holding Capacity Diseased bushes: Roguing of diseased bushes should be (inches of water progressing. This is important in all varieties but should per inch of soil) be done with extra care where blocks of Bluetta or Sand 0.05 Weymouth are located close to Blueray or Bluecrop. In Fine sand 0.08 the Pemberton area where there is still an appreciable Sandy loam 0.11 acreage of Rancocas, varieties adjoining this old variety Loam 0.16 should be carefully inspected. In such situations there Silt loam 0.18 seems to be a more rapid spread of Stunt Disease. The Clay loam 0.19 Rancocas is very resistant to this virus disease but it is Silty clay 0.20 susceptible and may be a source of the disease without Clay 0.22 showing symptoms vividly. After many years of harboring the disease some Rancocas bushes are now The following example shows how to determine the clearly exhibiting stunt symptoms. water-holding capacity of the rooting volume and how to All old plantings of Rancocas should be use this information to schedule irrigations. In this carefully rogued. Remember to spray diseased bushes example, assume that blueberries are planted on a sandy before removing them. It is necessary to kill the loam soil. Using a rooting depth of 1.5 feet, the total leafhoppers and it is more efficient, more economical, water-holding capacity of the rooting volume is 18 and wise from the standpoint of conservation of inches of soil times 0.11 inch of available water per inch beneficial insects to spray individual bushes rather than of soil depth, which equals 2 inches of total water- entire fields. holding capacity. The total water available in the Spraying entire blueberry fields with insecticide rooting volume should not drop below 50% of the total at this time will destroy many beneficial insects which water-holding capacity. This assures easy access to are now abundant. Bumble bees and other wild bees are water by the roots and prevents drought stress. Using busily foraging in goldenrod, boneset, aster, gerardin and this limit in the example, the total water available should other wild flowers. The killing of these effective not fall below 1 inch, which is half of the 2-inch total pollinators of blueberries is wanton and unwise. water-holding capacity. A blueberry plant growing Parasites and predators of leafrollers, leafminers, aphids vigorously in summer can evapotranspire more than 0.25 and scale are also numerous now in blueberries and their inch per day. With 1 inch of water available in the reduction by insecticides will make the problem of their rooting volume and approximately 0.25 inch being used control next year difficult. per day, it takes 4 days for the blueberry plant to use this stored soil water. Since the average time between rains Water Management: Blueberries have shallow root is 5 days, irrigation is highly desirable for this soil and systems that cannot use water stored deep in the soil. As site under peak use conditions. In general, blueberries a result, blueberries grow best where the soil has a high grown on light soils with low water-holding capacities water-holding capacity. Information about soil water- will benefit from irrigation most years, even in the holding capacity is generally available in soil surveys. humid regions. Reprinted: Highbush Blueberry Production Soil texture is another clue to water-holding capacity Guide. (Table 1). In general, sandy soils hold the least amount Sincerely, of water. These soils must be irrigated more frequently and with less water per application than soils with a high percentage of silt and clay. Dr. Gary C. Pavlis Atlantic County Agricultural Agent Editor - Blueberry Bulletin ma ❦ Page 2 Blueberry Bulletin, Vol. XVII, No. 15 At. Co. Blueberry Trap Averages WEEK END CBFW RBLR OBLR SNLH OR BEETLE BBM 20-May 4.79 16.63 0.00 27-May 6.00 1.94 0.33 3-June 2.66 0.19 13.67 10-June 0.94 20.22 14.00 0.10 10.00 0.00 17-June 0.44 102.88 1.50 0.42 428.64 0.01 23-June 0.32 146.73 0.00 0.37 1042.33 0.02 29-June 0.06 91.13 0.00 0.16 1355.00 0.02 6-July 0.00 79.11 0.00 0.11 1591.47 0.17 13-July 0.00 29.33 0.00 0.04 875.59 0.67 20-July 0.00 8.11 0.00 0.01 198.87 1.21 Burl. Co. Blueberry Trap Averages WEEK END CBFW RBLR OBLR SNLH OR BEET BBM 20-May 4.30 4.14 27-May 4.56 0.67 3-June 26.68 0.50 10-June 11.40 0.14 4.00 7.27 30.00 0.00 17-June 4.09 12.29 4.00 11.62 75.57 0.15 23-June 4.73 94.43 3.00 8.02 600.13 0.06 29-June 0.32 107.57 2.00 3.50 271.80 0.15 6-July 0.00 60.71 0.00 3.02 1016.00 0.27 13-July 0.05 31.43 0 1.55 657.90 0.90 20-July 0.00 5.00 0 0.79 212.50 0.17 Insect Trap Count Key: RBLR=redbanded leafroller, OBLR=obliquebanded leafroller, CBFW=cranberry fruitworm, SNLH=sharpnosed leafhopper, BBM=blueberry maggot. Blueberry Bulletin, Vol. XVII, No. 15 Page 3 BLUEBERRY RECIPES CHARLENE'S BLUEBERRY PIE BLUEBERRY SALAD MOLD 1 baked 9 inch shell or graham cracker crust 1 envelope unflavored gelatin 1 qt. fresh blueberries, rinsed and drained 1/2 cup cold water juice and rind of 1 lemon (2 Tbsp. juice) 1 cup hot water 3/4 cup sugar 1/3 cup sugar 3 Tbsp. cornstarch 1/8 tsp. salt 1/4 tsp. salt 1/4 cup lemon juice 3/4 cup water 2 cups blueberries Topping: Soften gelatin in cold water. Add hot water, sugar, salt and 2-3 oz. pkgs. cream cheese, softened lemon juice. Stir well. Chill until thickened. Fold in 1 1/2 2 Tbsp. cream cups washed blueberries. Pour into mold. Chill until firm. 1/4 tsp. aromatic bitters Unmold on salad greens. Garnish with additional one-half cup 2 Tbsp. sugar of blueberries. Makes 6 servings. Combine 1 cup berries and next five ingredients. Cook over BLUEBERRY SHORTCAKE low heat, stirring until bubbles and thick. Cool to lukewarm. 2 cups sifted flour Fold in other berries. Spread in shell. Mash cheese and other 2 Tbsp. sugar three ingredients until soft and fluffy. Pipe decoratively on 3 tsp. baking powder top of pie. Chill. Note: Can use frozen "dry pack" berries. 1 tsp. salt Will be like cream pie. 6 Tbsp. shortening 2/3 to 3/4 cup milk BLUEBERRY TARTS 4 to 6 cups blueberries 1 1/2 Tbsp. cornstarch 1/2 cup sugar Sift together flour, sugar, baking powder and salt. Cut in 1/2 cup water shortening with a pastry blender until fine.