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Issue: 17-10August 4, 2017

In This IssueCrop Conditions2017 Grape HarvestFruit Bud Development in StrawberryUpcoming Events

Crop ConditionsGrapes are starting to ripen (veraison) in Lafayette.Marquette and Brianna are the earliest varieties andboth are about 2 weeks from harvest. Floricaneproducing blackberry harvest continues. Primocanefruiting blackberries and raspberries are just gettingstarted. Japanese beetles continue to be a majorproblem in addition to Spotted Wing Drosophila.Peach harvest is winding down in Lafayette.Japanese beetles were a major problem, but we onlyhad a small amount of peach scab. Apples harvest isunderway. Early varieties such as Pristine are stillproducing and a few others such as Gala are aboutready.

Mars table grapeat veraison

Marquettegrapes atveraison

Marquettegrapes netted for

bird protection

Apples coloringnicely

GoldRush

Redhavenpeaches final

harvest

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Primocaneblackberriesbeginning to

ripen

Blackberriesattacked by

Japanese beetles

Floricaneblackberries still

producing

Elderberriesripening

2017 Grape HarvestGrape harvest is just about to get started in thesouthern part of the state. Early varieties will beharvested starting next week. Most varieties areslightly ahead of normal this year. In Lafayette,Marquette and Brianna are at full veraison and sholdbe ready to harvest in the next couple of weeks. Wegenerally harvest Brianna the third week of August

and Marquette the first week of September.Depending the weather for the next couple ofweeks, we might be a bit early this year. Fruitquality overall is very good.With wine grapes, all fruit of a given cultivar istypically harvested from the vineyard or block at asingle time to coordinate winery activity and toreduce costs. It is important to plan carefully so thatthe harvest date coincides with the optimum fruitquality.Most vineyards have some degree of variability insoil type and drainage, sunlight exposure, wind,insect and disease pest, nutritional status, etc. Fruitfrom different parts of the block, from adjacentvines, as well as from different parts of the samevine can vary. Much of the variability can be reducedwith proper vineyard management, e.g. clusterthinning, shoot thinning, canopy management, etc.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, middle andbottom of clusters, and from exposed and shadedclusters. Some growers prefer to collect a sample of 5 to 10 whole clusters per block rather thanindividual berries to capture the variability withinclusters. Often sampling occurs from a few select“cardinal” vines in a block. Whatever approach isused, be sure to compare your sampling results tothe actual final harvest juice parameters at the pressto determine the accuracy of your sampling. Most ofthe time samples tend to over estimate the level offruit maturity, but not always.Fruit quality is comprised of several factors, themost important of which are sugars, organic acids,and pH. Other factors such as phenolics,anthocyanins, aroma and flavor compounds can bevery important to wine quality as well. And ofcourse, freedom from rots is an importantconsideration. Unlike some other fruits, grapes donot continue to ripen after harvest. Consequently, it

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is important to harvest grapes at the peak of qualityand with the desired parameters for the intendeduse.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 measure theseparameters can be purchased for about $500. Eachof these factors is important for determining properharvest time, but none alone can accuratelyestimate overall fruit quality. It is the balance ofsugars, acids and juice pH that is important to thewine maker. And of course, there are the subjectivequalities of seed and skin maturity, tannins,anthocyanins, flavors, aromas, etc. The BerrySensory Analysis method addresses evaluation ofthese more subjective factors such as skin, pulp andseed maturity. More needs to be done to adapt themethod for use with our Midwest varieties, but as adescriptive tool, it can be an excellent way forgrowers to go beyond the basics of sugar, acid andpH.Berry skin damage from rain cracking, bird pecksand bee damage can lead to sour rot by yeasts andvinegar spoilage bacteria. The vinegar (acetic acid)leads to high volatile acidity levels in the wine. Weexperienced major problems with sour rot last year.Growers need to closely monitor for development ofsour rot, especially if rains occur near harvest, andtake measures to reduce the spread by managingfruit flies and microbial organisms. Ultimately it maybe necessary 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 in ripeness.In most cases, late clusters will never catch up tothe rest, and will only reduce the overall quality ofthe crop at harvest. Now is a good time to drop anyundesirable fruit. Don’t expect your harvest crew tosort as they pick. Go through beforehand andeliminate the guesswork.

Fruit Bud Development inStrawberryJune bearing strawberries are “short day” plants thatset flower buds in response to short days. As we getinto late summer, days shorten and strawberryplants respond by setting the flower buds that willresult in the crop next spring. It is important tomaintain appropriate nutrition and soil water statusduring this time. General recommendations are tofertilize strawberry fields with 20 to 50 pounds ofactual nitrogen per acre per during late summer. Nitrogen rates depend upon amount supplied atrenovation and plant vigor. New fields with highvigor may not need additional nitrogen now, butolder fields should benefit. Irrigation during this timeis also extremely important if rainfall has not beensufficient in your area. We suggest about 1 inch perweek. Continue to irrigate strawberries through fallto assure a good crop next year. Also maintain goodleaf health by controlling leaf diseases.

Upcoming EventsSouthwest Purdue Agricultural Center High/LowTunnel Tour co-sponsored with Dept. of Recreation,Park, and Tourism Studies at Indiana UniversityAugust 10, 2017Vincennes, INContact Wenjing Guan, guan40@purdue.edu, or DanEgel at egel@purdue.eduRegistration: Call 812-886-0198Pinney Purdue Vegetable and High Tunnel Field Day– co-sponsored with Dept. of Recreation, Park, andTourism Studies at Indiana UniversityAugust 15, 2017Pinney Purdue Ag Center Wanatah, INContact Kym Schwinkendorf atkschwink@purdue.edu or 219-386-5232Registration: http://tinyurl.com/yc5lqvez or call219-386-5232Organic Vegetable Seed Production & VarietalSelection WorkshopAugust 22, 2017

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West Lafayette, INContact Lori Jolly-Brown ljollybr@ purdue.eduRegistration: http://tinyurl.com/y7da7dshHydroponic Workshop IISeptember 8, 2017Purdue University-HLAContact Lori Jolly-Brown ljollybr@ purdue.eduRegister at http://tinyurl.com/yb4dnwrhPurdue Wine Grape Team Fall Workshop

September 25, 2017Purdue West Lafayette campusContact Jill Blume blume@purdue.eduIndiana Horticultural CongressFebruary 13-15, 2018Indianapolis Marriott East Indianapolis, INContact Lori Jolly-Brown @ljollybr@purdue.eduVisit www.inhortcongress.org for more details

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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