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Issue: 16-10August 10, 2016

In This IssueCrop conditions, current growth stagesSymptoms of flyspeck and sooty blotchTissue analysis for grapes and small fruitGrape harvest 2016Strawberry fruit bud developmentSpotted Wing DrosophilaUpcoming events

Crop conditions, currentgrowth stages(Bruce Bordelon, bordelon@purdue.edu, (765) 494-8212) &(Peter M Hirst, hirst@purdue.edu, (765) 494-1323)

Grape harvest has began in the southern part ofthe state and will begin in central areas over thenext week or so. Early varieties are nearing fullmaturity while late varieties are just at, or not yetat veraison. Overall fruit quality looks excellent.Apple harvest continues. Summer varieties aremostly done and early fall varieties are almostready. Primocane fruiting blackberry harvestcontinues into its second week on Black magic,with APF-45 not yet ready. First crop of Heritageand Caroline primocane fruiting raspberries areripening this week. Pressure from spotted wingDrosophila and Japanese beetles in brambles isstill very high and growers should continuecontrol measures. Incidence of white drupeletdisorder is common due to the high temperaturesthis year. Strawberry plantings are underconsiderable stress from heat and lack ofmoisture. Irrigation is highly recommendedespecially as fruit bud development nears.

Chambourcingrapes justbeginningveraison

Traminettegrapes are at

veraison

Marquettegrapes near full

harvestmaturity

Zestar applesready toharvest

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Silken applesready toharvest

Black Magicprimocane

fruitingblackberry at

harvest

Heritageraspberries at

harvest

Symptoms of flyspeck andsooty blotch(Janna L Beckerman, jbeckerm@purdue.edu, (765)494-4628)

The symptoms of flyspeck and sooty blotch havebegun to make their appearance. I know thisbecause 1). I’m starting to see spots, and 2). Wehave accumulated MORE THAN enough hours ofpost- petal fall leaf wetness needed for infectionto occur.

On no-spray or poorly managed orchards,flyspeck and sooty blotch are probably the leastof your problems.

First, what is enough hours of post- petal fall leafwetness needed for infection to occur? Differentstates have developed different levels andstandards, with highs of 270 hours (hours mustbe greater than 4 hrs to be counted) needed inNorth Carolina, compared to 175 period identifiedin Iowa. In Kentucky, John Hartman found185-251 hours were needed, but did not stipulatethat a minimum of 4 hrs was required toaccumulate leaf wetness. We have not yetdeveloped a guideline for Indiana. In the interim,using either the Iowa or Kentucky model mayreduce your fungicide usage in a normal year.For much of Indiana, ‘normal’ is a state we hearabout—a utopia between our extremes of tropicalrainforest (2015, 2016) and drought (2012).Sprays: Topsin-M tanked with captan is aneffective combination (Ziram is another option). However, some orchards may be experiencingTopsin-M resistant flyspeck and sooty blotchpopulations. If you suspect you are one of thoseorchards with SBFS fungicide resistance, or youwere late getting started, use Flint or Pristine toeradicate any infections that may have started. Thereafter, captan alone at appropriate intervals(2 weeks or 2 inches off rain; 10 days or 1.5inches of rain) should provide fair to goodcontrol. If disease pressure is high, and youhaven’t exceeded your four applications of

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strobies, Pristine or Flint all provide the bestprotection against this disease complex. We donot know if these fungicides are protectingagainst the disease, or are effective eradicants,but we do know that they work quite well againstthis complex.

Tissue analysis for grapesand small fruit(Bruce Bordelon, bordelon@purdue.edu, (765) 494-8212)

Plant nutritional status is important for all phasesof plant growth and has a direct effect on vigor,fruitfulness, cold hardiness, and other factors.Tissue analysis is the most reliable means ofdetermining plant nutritional status. Combinedwith soil testing, tissue analysis can help pinpointthe source of problems and determine whatmeasures may be needed to insure propernutrition of the crop. Tissue analysis samplesshould be collected at the appropriate time togive the most meaningful results. For strawberry,sample the first fully expanded leaves afterrenovation, usually in mid to late July. Forbrambles, sample leaves on non-fruiting canes(primocanes) between August 1 and 20. Forblueberries sample leaves during the first weekof harvest. For grapes, samples should be takenabout 70 days after full bloom, usually early tomid August. Samples should be adequate in size.Collect 30-60 leaves for strawberries, brambles,and blueberries, and 100 leaf petioles for grapes(for grapes submit only the leaf petiole, or stem,for analysis, discard the leaf blade). Collectsamples to represent the entire field, not justfrom a few plants. Sample different varietiesseparately. If specific problems exist, collectseparate samples from both normal andproblematic areas of the planting. Aftercollection, leaves should be washed gently to

remove any pesticide residues and dust thatmight affect analysis, laid out to dry for a coupleof days, then bagged in paper bags forsubmission to the lab. Some labs offer tissueanalysis sample kits.There are several private companies and a fewuniversities that provide tissue analysis. A list ofcertified soil and plant analysis testing labsserving Indiana growers is locatedat http://tinyurl.com/hm2b3q2The Midwest Small Fruit Pest ManagementHandbook has a chapter on tissue analysis andfertilizer recommendations.

Grape harvest 2016(Bruce Bordelon, bordelon@purdue.edu, (765) 494-8212)

Grape harvest is just getting started in thesouthern part of the state. Early varieties havebeen harvested for the past week. Most varietiesare slightly ahead of normal this year. Fruitquality overall is very good. Many vineyards arestill recovering from the winter of 2014 so yieldswill still be below normal.With wine grapes, all fruit of a given cultivar istypically harvested from the vineyard or block ata single time to coordinate winery activity and toreduce costs. It is important to plan carefully sothat the harvest date coincides with the optimumfruit quality.Most vineyards have some degree of variability insoil type and drainage, sunlight exposure, wind,insect and disease pest, nutritional status, etc.These variations can result in large differences infruit ripeness and quality. Fruit from differentparts of the block, from adjacent vines, as well asfrom different parts of the same vine can vary.Much of the variability can be reduced withproper vineyard management, e.g. clusterthinning, shoot thinning, canopy management,etc.

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As harvest nears, it is very important to monitorgrape chemistry. Growers should sample weeklyleading up harvest with a protocol to collect arepresentative sample of fruit from the entirevineyard. This can be a sample of 200 berries perblock collected from vines randomly, but withemphasis on collecting berries from top, middleand bottom of clusters, and from exposed andshaded clusters. Some growers prefer to collect asample of whole clusters rather than individualberries to capture the variability within clusters.Whatever approach is used, be sure to compareyour sampling results to the actual final harvestjuice parameters to determine the accuracy ofyour sampling. Most of the time samples tend toover estimate the level of fruit maturity.Fruit quality is comprised of several factors, themost important of which are sugars, organicacids, and pH. Other factors such as phenolics,anthocyanins, aroma and flavor compounds canbe very important to wine quality as well. And ofcourse, freedom from rots is an importantconsideration. Unlike some other fruits, grapesdo not continue to ripen after harvest.Consequently, it is important to harvest grapes atthe peak of quality and with the desiredparameters for the intended use.Wine grape growers should have the ability ofmeasure sugar content (with a refractometer),titratable acidity and pH (with a pH meter andburette). Equipment and supplies to measurethese parameters can be purchased for about$500. Each of these factors is important fordetermining proper harvest time, but none alonecan accurately estimate overall fruit quality. It isthe balance of sugars, acids and juice pH that isimportant to the wine maker. And of course,there are the subjective qualities of seed andskin maturity, tannins, anthocyanins, flavors,aromas, etc. The Berry Sensory Analysis methodaddresses evaluation of these more subjective

factors such as skin, pulp and seed maturity.More needs to be done to adapt the method foruse with our Midwest varieties, but as adescriptive tool, it can be an excellent way forgrowers to go beyond the basics of sugar, acidand pH.Bird pecks, cracks from rain, and bee damagecan lead to sour rot and its vinegar spoilagebacteria. The vinegar (acetic acid) leads to highvolatile acidity levels in the wine. Growers needto closely monitor for development of sour rotand take measures to reduce the spread bymanaging fruit flies. Ultimately it may benecessary to develop a strategy to minimizeharvest of rotted clusters. A pre-harvest walkthrough the vineyard block should identify anyclusters with sour rot and those lagging inripeness. In most cases, late clusters will nevercatch up to the rest, and will only reduce theoverall quality of the crop at harvest. Now is agood time to drop any undesirable fruit. Don’texpect your harvest crew to sort as they pick. Gothrough beforehand and eliminate theguesswork.

Strawberry fruit buddevelopment(Bruce Bordelon, bordelon@purdue.edu, (765) 494-8212)

June bearing strawberries are “short day” plantsthat set flower buds in response to short days. Aswe get into late summer, days shorten andstrawberry plants respond by setting the flowerbuds that will result in the crop next spring. It isimportant to maintain appropriate nutrition andsoil water status during this time. Generalrecommendations are to fertilize strawberryfields with 20 to 50 pounds of actual nitrogen peracre. Nitrogen rates depend upon amountsupplied at renovation and plant vigor. New fields

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with high vigor may not need additional nitrogennow, but older fields should benefit. Irrigationduring this time is also extremely important ifrainfall has not been sufficient in your area. Wesuggest about 1 inch per week. Continue toirrigate strawberries through fall to assure a goodcrop next year. Also maintain good leaf health bycontrolling leaf diseases.

Strawberry crown

Spotted Wing Drosophila(Ricky E Foster, fosterre@purdue.edu)

Spotted wing drosophila continue to plagueraspberry, blackberry, blueberry, and grapegrowers. I have had some reports of poor control.There are a number of reasons that control ofany insect may be poor. If you are not getting thelevel of control you expect, here are a few thingsto consider.

Is your sprayer calibrated correctly? Are you1.putting on the right amount of insecticide?Is your coverage adequate? Yellow water2.sensitive cards can be an economical way

to determine is the spray is getting whereyou need it to be.What is the pH of your water? If it is too3.high, you may need to adjust it to get downclose to 7 or below.How hard is your water? If the hardness4.level is 250 or higher, you may need tosoften the water before mixing theinsecticide.What is the interval between sprays? For5.this insect, weekly sprays appears to be thebare minimum. Some growers are sprayingtwice weekly and getting good results, butan interval of 4-5 days should be sufficientin most cases. I know that’s pretty close totwice per week but over the course of theseason you might save a spray or two.

Growers should expect to continue spraying tocontrol SWD until the end of the season. Our dataso far show that they remain active as long asyou are picking.

Upcoming events(Peter M Hirst, hirst@purdue.edu, (765) 494-1323) & (BruceBordelon, bordelon@purdue.edu, (765) 494-8212)

Indiana Horticultural Congress at the NEWLOCATION January 10-12, 2017Indianapolis Marriott East Hotel, 7202 East 21stStreet, Indianapolis, IN 46219.Purdue Wine Grape Team FallWorkshop: Purdue Meigs Horticulture ResearchFarm and West Lafayette campus. Moreinformation to follow.

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Facts for Fancy Fruit © Purdue University - fff.hort.purdue.eduEditor: Peter M Hirst | Department of Horticulture and Landscape Architecture, 625 Agriculture Mall

Dr., West Lafayette, IN 47907 | (765) 494-1323