630 US ISSN 0271-9916 March 1993 RESEARCH EXTENSION SERIES 141

FIELD TOMATO PRODUCTION GUIDELINESFOR HAWAII

Hector Valenzuela, Randall T. Hamasaki,and Ted M. Horl

HITAIlR • COLLEGE OF TROPICAL AGRlCUL11JRE AND HUMAN RESOURCES UNIVERSITY OF HAWAn

The Library of Congress has catalogued this serial publicationas follows:

MCR2 MARC-S[8606]Library of Congress

Research extension series / Hawaii Institute ofTropical Agri-culture and Human Hawaii]:

The Institute, [1980-v. : ill. ; 22 cm.

Irregular.Title from cover.Separately catalogued and classified in LC before and

including no. 044.ISSN 0271-9916 =Research extension series· Hawaii

Institute of Tropical Agriculture and Human Resources.1. Agriculture-Hawaii-Collected works. 2. Agricul-

ture---Research-Hawaii-Collected works. I. HawaiiInstitute of Tropical Agriculture and Human Resources.II. Title: Research extension series· Hawaii Institute ofTropical Agriculture and Human Resources.S52.5R47 630'.5-dcI9

THE AUTHORSHector Valenzuela is Assistant Extension Vegetable Specialist. College of Tropical Agriculture andHuman Resources. University of Hawaii.

Randall T. Hamasaki is Assistant County Extension Agent. College of Tropical Agriculture andHuman Resources. University of Hawaii.

Ted M. Hod is County Extension Agent, College ofTropical Agriculture and Human Resources. Univer-sity of Hawaii.

CONTENTSPage

Introduction 1Fertilizer Recommendations 2Culture and Management Practices 2Pests 3Harvest and Postharvest Practices 7References 12

FIELD TOMATO PRODUCTION GUIDELINES FOR HAWAII

Hector Valenzuela. Randall T. Hamasaki. and Ted M. Hort

·Requires staking and pruning.

Table 1. Cultivars adapted to Hawaii

Cultivars that have performed well inHawaii based on Molokai winter trials (wherespotted wilt has not been detected) include'Milagro', 'Celebrity', 'Carmen', 'Cavalier', and'Carnival'. On Molokai, 'Celebrity' was the mostproductive, with experimental yields of over50,000 lbjacre (56 MTjha).

fruit size, shape, color, firmness, and smooth-ness. Market traits to consider include pack-out,fruit size and shape, ripening, firmness, andflavor.

In Hawaii, 'Celebrity' is the industrystandard for bush-type tomato, but productionof this semideterminate cultivar has decreaseddramatically over the last few years due to itssusceptibility to TSWV. PetoSeed has recentlyreleased hybrid cultivar 'PSR 55289' withresistance to TSWV and with horticultural traitssimilar to those of 'Celebrity'. Its future avail-ability will depend on local grower demand. SeeTable 1 for a list of cultivars adapted to Hawaii.

Large Plum or Cherryfruited paste type type

Cultivar

Open pollinatedHealani +Tropic* +8222 +8248 +Roma +San Marzano +Large Red Cherry +Royal Red Cherry +Hybrid cultivarsPetoSeed PSR 55289 +Celebrity +N-52* +N-65* +N-69* +BWN-21 +Small Fry +Cherry Challenger +Cherry Grande +Sweet Million +

INTRODUCTIONThe tomato, Lycoperstcon lycoperstct. is the

number one vegetable crop in Hawaii in terms ofpopularity and market value. This uniquevegetable, a member of the family Solanaceaealong with the peppers and the Irish potato, is anative of Central and South America. Nutri-tionally, a medium-sized tomato (5.3 oz) con-tains 35 calories and is rich in vitamin C,vitamin A, potassium, and fiber. It is a warmseason crop, grown in Hawaii from sea level upto 6000 ft in elevation.

In 1991, 14 million lb (6400 MT) of tomatoeswere consumed in Hawaii, of which 23 percentwere produced locally on 230 acres (95 hal. Thefarm value of local production of tomatoes inHawaii for 1991 was about $3.1 million, withproduction concentrated in Kona, MountainView, Kula, and on Molokai. Local productionhas decreased substantially over the past fewyears due to crop losses caused primarily by thetomato spotted wilt virus (TSWV).

Flowering and FruitingThe tomato is self-pollinated. Flowers are

borne in clusters located on the stem between thenodes. Tomatoes, especially the large-fruitedvarieties, are sensitive to high nighttimetemperatures, which may lead to lower fruit setor to development of small, seedless fruit.Optimum temperature for fruit set is 6O-70°F

Fruits reach the mature green stageabout 27 days after fertilization. Environmentalstress such as poor nutrition, unfavorableweather, or insect and disease pressure mayresult in abscission dUring or after flowering.

CultlvarsCultivar selection is one of the most

important decisions made during the cropproduction process. Selection of cultivarsadapted to local growing conditions and seedquality are Significant production factors thatdeserve careful planning and consideration.Cultivars developed by the University of Hawaii,now over 15 years old, have resistance tobacterial wilt, vascular browning, fusarium wiltrace I, common races of root-knot nematode(gene Mil, spotted wilt virus (gene Swa) ,Stemphylium solant, and spider mites. Growthcharacteristics to consider during cultivarselection include plant habit, jointlessness, and

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Table 2. Recommended nutrient ranges fortomato

stage. At the seedling stage, apply weekly 2-5percent of the total N and K requirements. At theearly fruiting stage, begin weekly applications of10 percent of the total N and K requirements.

CULTURE AND MANAGEMENT PRACTICESIn typical commercial operations, tomatoes

are grown in polyethylene-mulched beds withdrip irrigation. Irrigation and fertilization canbe monitored closely with drip irrigation. Theplastic mulch helps to maintain efficient use ofwater and fertilizer. Tomatoes are susceptible to

Nutrient Tissue AnalysisPeriodic nutrient analysis of foliage tissue

may be used to provide an estimate of a crop'snutritional status and seIVe as a record of cropperformance. The tissue analysis should becalibrated with soil fertility levels, according tosoil samples taken before planting. For tissueanalysis, collect a young mature whole leaf(petiole and leaflets) located below the last openflower cluster. A representative tissue samplefrom a field will consist of 25 to 100 collectedleaves free of insects or disease. The criticalgrowth stage of phosphorus uptake is when thefirst flower cluster develops, and tissue levelsshould thus be maintained above 0.4 percent toavoid flower abortion. With rapidly growingplants the calcium level must be maintainedabove 2.5 percent from the first flower set andpreferably throughout the plant life cycle.Excessive nitrogen applications resulting· intissue levels >5 percent will inhibit calcium andpotassium uptake, reduce internode length, andpromote excessive vegetative growth. Recom-mended optimum ranges for tomato are found inTable 2.

3.0%0.5%3.5%3%0.4%

120 ppm25 ppm75 ppm10 ppm25 ppm0.16 ppm

Target levelRange

3.0-4.5%0.4-1%3.0-7.OOA>2.0-5.0%0.4-1.5%

100-250 ppm25-150 ppm4G-300ppm5-25 ppm25-100 ppm0.15-5.0 ppm

Nutrient

NPKCaMgFeZnMnCuBMo

OptlmumpHThe optimum pH is 6.0-6.5. Liming to raise

the pH to 6.0-6.5 may aid in reduCing fusariumwilt in the field.

Nutrient RatesFertilizer applications should be based on

crop nutrient demands and stage of crop growth.Tissue and soil analysis will help to determinehow much fertilizer to apply to complement thenutrient levels already available in the soil. Soilsamples should be taken and appropriatefertilizers added as recommended by Universityof Hawaii soil scientists for the particular soiltype. Excessive fertilizer application beyondcrop needs may result in salt buildup, phytotoxiceffects on plant growth, groundwater contam-ination, and capital losses due to purchase ofunneeded fertilizer. Recommended rates forHawaii are 1500-2000 lb/acre of 10-20-20 orsimilar fertilizer, with half applied at plantingand the remainder four to five weeks later.Supplemental 100 lb/acre urea or 200 lb/acresulfate of ammonia can be applied every three tofour weeks after haIVest begins. Phosphorus isan important nutrient for root development,flower development, fruit set, and fruit matura-tion.

On soils that test low for phosphorus, apply1000 lb/acre treble superphosphate. ThiS isapplied preplant in 12-inch (30 em) bands in theplant row and worked to a depth of 6-12 in (15-30 em). Soil magnesium deficiencies are cor-rected with 150-200 lb/acre magnesium sulfate.Minor crop magnesium deficiencies may becorrected as needed with magnesium sulfate(epsom salt) sprays of 10 lb/loo gal water peracre.

An adequate calcium supply is necessary toprevent blossom-end rot in tomatoes. Calciumdeficiencies are corrected with weekly foliarcalcium nitrate or calcium chlOride applica-tions at rates of 10 lb/ 100 gal and 5 lb/ 100 gal,respectively.

FERTll.IZER RECOMMENDATIONS

FertWzer PlacementIn nonmulched crops, apply all P and up to

half the Nand K before planting, incorporatingwith disks or rototilling. Supplemental fertil-ization dUring the growing season should bebanded on both sides of the row.

For drip-irrigated crops, apply all phosphor-us, micronutrients, and 20 to 40 percent of totalNand K before laying the plastic mulch. Theremaining Nand K are applied at levelscorresponding with the crop developmental

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damage from wind, and growers in windy areasshould consider the use of suitable windbreaks.Protect your crop in wind-prone areas withwiliwili (Erythrina), yuba cane, or other shrubssuitable to your area. An in-field rotation maybe conducted for the following crop byrototUling the row where the windbreak wasgrown, planting in the row, and preparing thebed in that area.

Time to PlantIn HaWaii, tomatoes are grown year-round at

1000-3000 ft (300-1000 m) elevation, fromMarch through August at 3000-4500 ft (1000-1500 m), and from September through May fromsea level to 1500 ft (500 m).

Field PreparationPlow the soil if a hard pan is present. Lim-

ing, when necessary, is broadcast and diskedalong with any crop residue or weeds. Bedding,fertilizing, and fumigating may also be con-ducted at preplant.

PropagationTomatoes are normally transplanted in

Hawaii to assure proper stand establishment.Seedlings are transplanted three to five weeksafter sowing. About 1 oz of seed/acre is needed iftransplanted and 2 lb/acre if direct-seeded.

SpacingBush tomatoes are spaced 3-4 ft apart in

rows spaced 5-7 ft apart. Trellised plants arespaced 14-24 in apart on 5-ft-tall trellises withrows spaced 5-6 ft apart.

TransplantingSeedlings are grown in containerized plastic

or styrofoam multicell packs or similar systemsin which the cell surface area is 2 sq in (5 sq cm).These seedlings can then be transplanted withminimal disturbance to the root system. Earlyroot development is enhanced with soluble 10-52-17 or similar fertilizer when applied at 3-4Ib/50 gal water. The transplants are kept in agreenhouse or shadehouse. Follow proper sani-tary conditions by using sterile trays andsoilless growing media. The seedlings should becarefully monitored to maintain proper water-ing, nutrition, and disease-free material.

TrainingStaked tomatoes provide ease of harvest and

higher fruit quality by keeping fruits off theground and minimizing rot. Staked tomatoesare normally pruned to one or two main stems.Staking is done two to three weeks after

transplanting. Wooden stakes 50-60 in long aredriven into the ground halfway between eachpair of plants or between alternating pairs ofplants. Plants are trained by tying them withplastic twine or construction wire onto thetrellis beginning three to four weeks aftertransplanting: this is repeated three or fourtimes dUring the growing season. The twine istied around each stake and on both sides of theplant to provide vertical support. Before beingreused, stakes should be sterilized by steamingone to two hours at 200°F under a plastic tarp, orwith methyl bromide fumigation. Height of thestakes and training technique vary dependingon wind conditions dUring the growth cycle oron traditional practices followed in the differenttomato production areas of the state.

IrrigationDrip irrigation for tomatoes has gained

popularity because of its increased efficiency ofwater use and because it allows application offertilizers and pesticides with the irrigationwater (Fig. 1). With drip irrigation it is possibleto closely synchronize weekly water and nutri-ent application rates with the correspondingstage of crop development.

PESTSTomato yields may be reduced by myriad

insect and disease pests. Integrated pest man-agement (IPM) is a systems approach to reducepest damage to tolerable levels using a variety oftechniques such as natural enemies, geneticallyresistant plants, sound cultural practices, and,when appropriate, chemical pesticides. The IPMapproach is based on proper pest identification,periodic scouting, and the application of pestmanagement practices dUring the precise stageof the crop's development when no controlaction would result in significant economiclosses. Two additional strategies of an integrat-ed management approach are (1) taking pestcontrol actions dUring the most vulnerable stagein the pest's life cycle to maximize results withthe least possible effort, and (2) using syntheticpesticide spray applications for pest suppressiononly after all other pest control alternativeshave been considered and exhausted. The mainobjectives of using alternative pest controls areto reduce the high capital costs incurred withfrequent pesticide applications and to maximizethe abundance of benefiCial organisms.

InsectsImportant insect pests of tomato include

aphids, armyworms, cutworms, tomato fruit-worm, leafminers, melon fly, mites, root-knot

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nematodes, tomato pinworm, thrips, andwhiteflies. Outbreaks of the sweetpotato white-fly and the greenhouse whitefly are currently amajor problem for tomato production inHawaii. Apply insecticides only when necessaryand, when possible, rotate pesticide families todelay development of insect resistance. Insectswith exploding population growth rates such asthrips, whiteflies, mites, leafminers, and aphidsare especially prone to develop pesticide resis- .tance when exposed to frequent applications ofthe same insecticide.

Aphids. Aphids feed on plant sap, which mayreduce plant vigor. Aphids may also act asvectors of plant viruses and may introducetoxins into the plant, resulting in growthdeformations. Growers should use timelyinsecticide applications as needed based on closemonitoring of aphids and their natural enemies.

Annywonns. Beet armyworm (Spodopteraexigua) and nutgrass armyworm (S. exempta)infestations on tomato may cause fruit losses ofup to 25 percent. Armyworms can be dis-tinguished by the inverted "Y" on the front of thehead. Adult moths are active at night and canlay eggs on the leaves in groups of 100 or more.Feeding by young caterpillars can reduce leavesto veins, leaving only webs behind. Caterpillarsnormally begin feeding on the fruit after molt-ing three or four times, and they later pupate inthe soil. Damage to the fruit consists ofsuperficial feeding wounds that dry out as thefruit matures. Small caterpillars, however, maypenetrate the fruit and cause damage similar tothe feeding damage caused by the tomatofruitworm. A caterpillar normally feeds onmore than one fruit. Armyworms should becontrolled before they reach a length of 1/2 in.Monitor the crop weekly, beginning at fruit set.and apply pesticides when more than 0.25 larvaper plant (i.e., one larva per four plants) aredetected

Cutwonns. These caterpillar pests, whichinclude the variegated cutworm (Peridromasaucia) and the black cutworm (Agrotis ipsUon),can devastate young tomato plants by cheWingthrough the stems at the soil line. Cutworms areactive at night. Control is warranted when highpopulations are present in the field beforeplanting. Baits containing Bacillus thuringien-sis are available for cutworm control. Control isnormally not recommended when the plants areft tall.Tomato fruitwonn. The tomato fruitworm

(Helioverpa zea) damages green fruit. It is also animportant pest of corn, lettuce. beans. and othercrops. Eggs are laid Singly on leaflets close to thesmall fruits. The larva feeds on green fruit and

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later burrows into the soil to pupate. The pupa isformed in a tiny cell 2 in below the soil surface.Adults are active at dusk and dUring the night.Female moths begin laying eggs 48 hours afteremergence. Important natural enemies of thefruitworm include the parasitic wasps Tricho-grama spp. and Hyposoter exiguae, as well assome general predators. The critical period formonitoring beginS at flowering and lasts untilthe green fruit stage. Egg counts are made fromleaves below the inflorescence. Pesticide appli-cations may be needed when more than fourviable eggs are found in a sample of 30 leaves.Pesticide treatments are also recommendedwhen a large percentage of young caterpillars arefeeding on the foliage before fruit damage hasoccurred.

Leafminers. Leafminers are normally asecondary pest that is kept in check by naturalenemies. Both the vegetable leafminer (Lirio-myza sativae) and the celery leafminer (L.trifoliil may become primary pests, however, intomato fields where intensive pesticide use hasdestroyed their natural enemies. Leafminers aresmall yellow maggots that form trails beneaththe leaf epidermis as they feed. When fullygrown. the larvae drop to the soil to pupate. Amonitoring program consists of placing whitestyrofoam or plastic pans at the soil level belowthe plants throughout the field to collect larvaeas they drop and pupate. Insecticides are recom-mended when average counts rise above 20pupae/pan/day. Because contact insecticideswon't reach the larvae inside the leaf. systemicsare recommended.

Melonjly. The melon fly (Bactrocera cucur-bitae) has long been a major pest of tomatoes inHawaii. The pest has traditionally been con-trolled in problem areas with protein baits andan insecticide such as malathion applied to cornborder rows. Infested fruits should be removedfrom the field to reduce insect numbers. Do notdispose of culled fruit with live melon fly larvaein areas close to the production field.

Mites. Outbreaks of carmine spider mites(Tetranychus cinnabarinus) and the tomatorusset mite (Aculops lycopersici) may occurdUring hot. dry weather. Tomato russet mites aretiny spiderlike animals that feed preferentiallyon the lower stem, and then move on to feed onthe upper section of the plant and on leaves.Their life cycle-egg hatching and two nymphalstages until maturity-takes one week in hotweather. The presence of the mites is indicatedby the bronze, greasy appearance of stem andleaves. Similarly, the carmine spider mitecompletes its life cycle in about one week. Itsfeeding causes leaves to become stripped with

light-colored dots. Leaves may later tum yellowand drop. Silk webbing may be present wheninfestation is heavy. Wettable sulfur and othermiticides are effective against mites.

Root-knot nematodes. Root-knot nematodesare microscopic roundworms that feed on theroots of plants. Symptoms on the foliage causedby the affected root system include stunting.wilting. and leaf yellOWing. Infested rootsdevelop gall-like swellings. Adult stages of thenematode live inside these swellings in theroots. Before planting. tomato fields arenormally fumigated for nematode control.Many commercial cultivars. including the UH-bred lines. are resistant to root-knot nematodes.Several grasses that are nonhosts to the root-knot nematode. such as oats. barley. wheat. andrhodes grass, may also be grown beforetomatoes. Other nematodes that infest tomatoesinclude sting, stunt, reniform. and daggernematodes. The soil may be tested to estimatethe population of parasitic nematodes.

Tomato pinworm. The tomato pinworm(Ketjeria lycopersiceUa) is a small caterpillarthat can severely damage tomato. Crop lossescan reach 80 percent. despite the application ofinsecticides. The yellowish green larva is 1/4 inlong. Activity of the adult moth peaks between4:00 and 9:00 p.m.. at which time eggs are laidpreferably in leaves just above or below theinflorescence. Young larvae tend to live in theleaves. The leaf tips are tied together by thepinworm as it feeds, making it difficult to targetwith insecticide applications. While somepinworms complete their life cycle in the leaf. inmost cases third instar larvae perforate the fruitnear the calyx. The· pinworm normally pupatesin the soil, but in some cases it may pupate in thefruit itself. Alternative controls include theenhancement of parasitoids. clearing of weedyareas close to the production field. qUickdisposal of the crop after harvest. and estab-lishment of crop-free periods. A monitoringprogram for the tomato pinworm consists ofweekly egg and larval counts, assessment of fruitdamage. and adult counts with pheromone traps.Insecticide treatments are recommended whenlarval counts are above 0.25 per plant.

Thrips. The western flower thrips (Frank-linieUa occidentalis) is a vector for TSWV. Thisdisease has caused a dramatic decrease intomato acreage on Maui over the past few years.Thrips may also reduce plant vigor when feedingon tomatoes in large numbers. Their directdamage to fruit may cause bronzing.

Whiteflies. Recent sweetpotato whitefly(Bemisia tabaci) outbreaks have caused con-siderable losses in tomato fields statewide. The

main symptom is an irregular ripening of thefruit, which is difficult to distingUish on green-mature tomatoes. The irregular ripening symp-tom. which is probably caused by a toxininjected by the whitefly. is visible only afterripening, when the tomatoes have normallyreached the wholesaler (Fig. 2). Additional sort-ing operations and an in-house ripening stepmay be reqUired to reduce the numbers of poorlyripened fruit. Full canopy coverage with insecti-cide sprays is necessary to reach the eggs andadults on the underside of the leaves. Areawidecontrol strategies may be necessary in placeswhere whitefly numbers are abnormally high.The sweetpotato whitefly-transmitted geminivirus, which has resulted in stunting andreduced fruit size in Florida and California, hasnot yet been detected in Hawaii.

The greenhouse whitefly (Trialeurodes vapo-rariorum) is also common in Hawaii tomatoproduction areas. Parasitic wasps and predatorssuch as the tomato bug help to keep thegreenhouse whitefly below damaging levels. Incontrast to the case of the sweetpotato whitefly.tomatoes can sustain greater population levelsof the greenhouse whitefly without yieldreductions. Control strategies will thereforevary depending on the specific whitefly speciesin the field. Before conducting any pest controlmeasures. identify the whitefly species that isactually present in your field.

DiseasesBacterial canker. Corynebacterium michi-

ganense can be a serious disease in tomatobecause it can persist in the soil for many yearsand because it is seed-transmitted. Symptomsinclude wilting and cankers on stem and fruits.Drip inigation has reduced the incidence of thisdisease. For control. use disease-free or certifiedseed. Contaminated open-pollinated seed may betreated with the follOWing treatments:

1. Fermentation: Ferment crushed pulp for96 hours before extracting seed at temperaturesnear 70°F. Stir it at least twice a day.

2. Acid: Soak freshly extracted seed in an 0.8percent acetic acid solution. This is done byadding 1 fl OZ acetic acid to 1 gal water. Placeseed in loosely woven cloth and immerse insolution for 24 hours at 70°F.

Bacterial spot. Xanthomonas campestris pv.vesicatoria may become a problem dUring wetweather. Both foliage and fruits are affected.Infection occurs through natural leaf openingsor through wounds in the fruit. Fruits shownumerous I/s-inch spots. Leaves show irregular-ly shaped brown spot lesions. Destroy tomatoplants after harvest to reduce inocolum levels.

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Bacterial wUt. Pseudomonas solanacearumis the most serious disease of tomatoes in thetropics and subtropics. Symptoms include rapidwilt and death of the entire plant without anyyellowing of the leaves. If the stem is cut andplaced in a glass ofwater, a gray bacterial ooze isvisible. The disease is difficult to controlbecause it remains in the soil for many years.Contaminated fields should be rotated with non-solanaceous crops. Prevent machinery and fieldpersonnel from moving from contaminated tononcontaminated soils. The disease penetratesthe plant through wound openings in the roots.Old cultivars 'Kewalo' and 'BWN-21', developedby the University of Hawaii, are highly tolerantto bacterial wilt.

Blossom-end rot. ThiS physiological diseasemay cause severe yield reductions in tomato.The initial symptom will be a slight, water-soaked discoloration on the blossom end offruits. The lesions enlarge and tum dark brownor black. An irregular water supply compoundedwith a fast growing crop may promote blossom-end rot. The disease results from a localizedcalcium deficiency in the fruit. Calcium istranslocated in the plant through the tran-spiration flow. Being the major vascular systemsink, the leaves obtain the primary supply ofcalcium: when calcium deficiencies occur, thefruits are the first organs to show deficiencysymptoms. Factors that have an effect on theplant's calcium supply should be monitored:cultivar, plant nitrogen status, soil fertility, pH,and an even moisture supply in the root zone.Nitrogen overfertilization may accentuateblossom-end rot by promoting excessive shootgrowth.

Blotchy ripening. or gray wall. ThiS phys-iological disease, also called internal browning,is characterized by irregular browning on theside walls of the fruit. The fruits develop anormal red color except in the affected areas. Across section of affected fruits shows brownveins with yellow to gray cells in the blotchedareas. The incidence of blotchy ripening isincreased with tobacco mosaic virus (TMV)infection, succulent growth, low potassium, andsudden temperature changes. Commercial cul-tivars have good resistance to this disease.

Caiface. In this phySiological disorder, fruitsshow extreme malformation and scarring at theblossom ends. Catface results from any growthfactor that affects normal pistil development inthe flower. Prolonged heat dUring blossomingand other stress factors may result in catfacing.Most commercial varieties are not affected bycatface. Remove affected fruits as soon aspossible so that remaining fruits are allowed to

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develop.Double streak virus. ThiS disease is

normally a combination of TMV and potatovirus X or Y. A combination ofTSWV and potatovirus Y can also cause the disease. The initialsymptom is light green mottling of leavesfollowed by development of small grayish brownspots on leaves. Later, brown spots appear onstem and leaf petioles. Infected plants arestunted and fruits, if produced, are covered withdark spots. The virus complex is transmittedmechanically. Controls include grOWing TMV-resistant cultivars and determinate cultivarsthat do not require pruning (Fig. 3).

Early blight. Symptoms of the fungusAlternaria solani are concentric lesions of deadtissue on leaves and stems, as well as spotting onleaves and fruits. The disease can result in cropdefoliation dUring wann, wet weather any timedUring the crop cycle. Controls include a three-year rotation: planting on wide, high beds: andfungiCide treatments.

Fruit cracks. Three common types of phys-iological cracks make fruits unsalable andpermit the entrance of secondary diseaseorganisms: (1) radial, in which cracks radiatefrom the stem: (2) concentric, in which cracksextend ina more or less circular fashion aroundthe stem-end portion of the fruit, and (3)splitting or bursting, which occurs in nearly ripefruit after rain or irrigation. Cracking can bepartially controlled by prOViding an evenmoisture supply, thus preventing alternatingstages of fast and slow fruit growth.

Fusarium wilt. Fusarium oxysporum f.lycopersici is a soilborne fungus that enters theplant through the root and interferes with theplant's vascular system by stopping thetranspirational flow. As a consequence, thelower leaves are the first to turn yellow andwither. The symptoms progress and eventuallythe entire plant is affected. with a dark browndiscoloration in the bark of affected areas andwith live leaves limited to the branch tips.Commercial cultivars are available with resis-tance to races 1 and 2. In addition, sanitation.rotation with grass crops. soil fumigation, andsoil pH near 6.5 should be used for control ofraces 1,2, and 3.

Gray leaf spot. Stemphylium solani beginsas small, circular, sunken brownish lesionswith spots surrounded by a yellow halo. Thefungus is favored by hot weather, and it cancause severe defoliation in susceptible cultivars.Best control is achieved with resistant cultivars.Destroy the tomato crop promptly after halVest.

Late blight. Phytophthora infestans causessevere defoliation, stem girdling, and severe

fruit rot. Cool nights and warm days withabundant moisture favor development of thisfungus. Fruit symptoms include irregular water-soaked spots that tum brown and wrinkle at thesurface. Control includes careful monitoringand use of fungicide applications.

Puifiness. This phySiological fruit disorderis common dUring the winter or early spring.Affected fruits are light and feel soft. Fruit shapeis normal, but the surface is flattened orshrunken over the sections between the internalwalls. Fruit cross sections show a normallydeveloped outer wall and poorly developed seedlocules, with existing cavities between thelocules and the outer wall. Factors that maypromote puffiness include poor pollination,excessive N applications under cloudy weather,excessive irrigation, and temperature extremes.

Sclerotinia. Sclerotinia sclerotiorum cancause serious losses in both tomato greenhouseand field operations. The fungus attacks themain stem at the soil line and is characterizedby water-soaked areas that become light to darkbrown. Further disease development results inwilting and plant death. Masses of white moldand black sclerotia are identifying character-istics. High moisture and temperatures promotedisease development. Control the disease withproper sanitation, soil drainage, crop rotationwith grass crops, and fungicide applications.This disease may build up in nearby bean fields.

Tomato spotted wat virus. Growth ceasesand the tomato plant ages qUickly after infec-tion with TSWV. In older plants, leaves near thegrowing tips show dark bronze or purplishcircular, necrotic spots. Fruits also showcircular concentric marks (Fig. 4). TSWV is theonly virus known to be transmitted by thrips.The only effective means of control is resistantcultivars. 'Celebrity', the standard tomato cul-tivar in Hawaii, is highly susceptible to the newstrain of spotted wilt. The PetoSeed hybrid 'PSR55289' has shown resistance to TSWV and hascomparable horticultural traits to ·Celebrity'.

Tobacco mosaic virus (TMV). Symptomsinclude mottling or mosaic effects on the leaves.Infections occurring when plants are young cansignificantly reduce yields. The virus is trans-mitted mechanically, through pruning andstaking, and by field workers. Several com-mercial varieties are resistant to TMV.

WeedsAn integrated approach can be used to

manage weed competition in tomato production.The IPM program for weed control uses weedidentification, monitoring, sanitation, alter-native cultural practices, and timely herbicide

applications. A weed map for each field helps inthe design of weed control measures and is arecord of weed problems in the field. Culturalcontrol practices for weed control includeshallow cultivation, plowing, disking, hoeing,crop rotation, cover cropping, living mulches,organic or plastic mulching, and herbicides. Thebenefits of proper field preparation cannot beoveremphasized to improve tomato growth andminimize weed problems dUring the crop growthcycle.

Useful crops for rotation with tomatoinclude alfalfa, sugarbeets, and onions. Sola-naceous crops such as potatoes and pepper arenot recommended as rotation crops withtomato. Problem weeds in tomatoes includeperennials, dodder, weeds of the nightshadefamily (solanaceous family), and grasses. Thecritical weed-free period for tomatoes (I.e., thenumber of days the field has to be kept weed-freeafter transplanting to prevent yield losses due toweed competition) is estimated to be between 30and 35 days after transplanting.

HARVEST AND POSTHARVEST PRACTICES

TimingTime from transplant to first harvest is

generally 70-75 days for cherry types, 75-80days for plum types, and 80-90 days for large-fruited tomatoes.

Production YieldsIn Hawaii, bush tomato culture yields 20,000

lb/acre. while trellised tomato culture yields30,000 Ib/acre. The average Florida yield is30,000 Ib/acre, and the average Ohio yield is13,500 Ib/acre.

MaturityTomato fruits mature about 25-30 days after

pollination. Maturity is· correlated with in-creased fruit size, weight, specific gravity, totalacidity. and hydrogen concentration. Grades forfresh tomatoes are U.S. No.!, U.S. Combination,U.S. No.2, and U.S. No.3. Fruit category sizes fortomatoes are large, 7.2 oz (205 g): medium, 5.3 oz(150 g): and small, 4 oz (l15 g). Harvesting stagesfor tomato include immature green, maturegreen, tUrning, half-ripe or pink, and ripe or red-ripe. Indices of maturity for green pickedtomatoes include (1) size, which varies withcultivar: (2) a rounded shape, not angular: (3) awhitish green color development in the blossomend: (4) development of a brown corky tissue onthe stem scar of some cultivars: and (5) arepresentative sample of the fruit's internalappearance (the preferred method but a destruc-

7

8

FlQ:. 3. The 11M of det.e:nninate eu.ld.....n elil:n1Date. the Deed101' puaiDC.

Fla:. 4. TSWV·lafccted tomato fruit. ezbiblt the typicalcircular blerolahe.o

1Hawaii growers should check with the Hawaii DepartmentofAgricufture for current tomato grade standards.

StorageTomatoes should be stored at temperatures

above 55°F (l3°C). To delay ripening of tomatoesat a particular stage. they can be held in a roombelow 68°F (20°C). Chilling injury occurs below50°F (lO°C).

Market InformationIn 1990 the state imported about 14 million

lb of tomatoes. or =70 percent of the volumeconsumed locally. The potential for the industryis to produce 100 percent of the local demanddUring the summer months and 40 percent

PackagingMature greens are sold in 25-lb bulk-packed

cartons. Fruits are packed in each carton basedon fruit number per row and column in a two-layered tomato package. Pink and vine-ripetomatoes are packed in two-layer lug or traypacks. Cherry tomatoes are packed in flats. holding 12 I-pint boxes. Plum tomatoes arepreferably packed in quart boxes. eight percarton. To avoid bruising. cartons are notstacked more than two layers high. Fruit ispacked stem up. to protect the shoulders.

>3 15/3Z228/3Z217/3Z29 /3Z24 /3Z

Inchesmin max

3 15/3Z228/3Z2 17/3Z29 /3Z27 /3Z128/3Z

>4x55x5.5x66x66x77x77x8

SizeName

Table 3. Sizing of tomatoes1

MaximumlargeExtra largeLargeMediumSmallExtra small

ripening caused by the sweetpotato whitefly.Preliminary research conducted at the Univer-sity of HaWaii. however. did not show improvedripening uniformity with ethylene treatment:instead. it indicated the need to improveharvesting techniques and training of theharvesting crew to pick fruit at the same stage ofphysiological maturity. Optimum ripening isobtained when the ripening rooms are main-tained at 68°F and 90-95 percent relativehumidity at ethylene concentrations of 150ppm. Ethylene is normally applied with on-sitecatalytic generators or with flow-throughsystems.

tive test). Both cherry and plum tomatoes arenormally picked vine-ripe.

Harvesting OperationIn large field operations. fresh market

tomatoes are hand-picked in 40- to 5O-lb bucketsand placed in bins. where a truck takes them tothe packing shed. An alternative harvestingoperation consists of a conveyor belt on groundtomatoes. Pickers travel a few feet to theconveyor belt. where the tomatoes are placedand conveyed into the loading truck. Bruising oftomatoes from excessive handling and unload-ing is significantly reduced with the conveyorbelt. Tomatoes should be kept in the shade untiltaken to the packinghouse. where they arewashed. presized. sorted. graded. Sized. packed.unitized for shipment. and shipped to theirdestination market.

Washing TomatoesWater for washing tomatoes should be at or

above the temperature of the tomatoes. Coolerwater will be absorbed by the fruits. Wash watermanagement practices should be an importantconsideration dUring the handling process toprevent the spread of postharvest diseases.Decayed fruit should be culled to eliminatepotential sources of inoculum. Wash water ischlOrinated at 150 ppm. and fruits are held inthis water for no longer than two minutes in asingle layer of floating tomatoes.

Ethylene TreatmentIn Hawaii. some green-picked tomatoes are

treated with' ethylene to enhance and promoteripening uniformity. Some growers have movedto ethylene treatment to overcome the irregular

Presizing, Sorting, and SiZingTomatoes with a diameter of less than 2 in

are culled. This operation is carried out throughan automatic presizer in large commercialoperations. Sorting and grading is conductedVisually in the packinghouse by separatingtomatoes based on USDA color stages. Thisoperation takes on a double effort when sortingout tomatoes with irregular ripening symptomsbrought about by sweetpotato whitefly feedingon the crop dUring the growing season. Largercommercial operations on the U.S. mainlandare moving toward the use of automaticelectronic color sorters such as the onesdeveloped for apples. Tomatoes are then sizedbased on market classifications and conveyed tothe packing line. They are normally packed in25-lb cartons and unitized on 2000-lb pallets.See Table 3 for more information on sizing.

9

dUring the winter months. If the industry couldproduce 70 percent of local demand, the farm-gate value would be $8.46 million, based onproduction of 13 million lb and the 1990 averageper pound price of 65 cents.

A solid tomato production program includesa sound and well planned marketing strategy.The prospective grower needs to have a goodunderstanding of annual market trends (seeFigs. 5,6, and 7), market competitors, consumerneeds, potential buyers, and market windows.To keep abreast of changing market situationsand new business opportunities, producers needto be in close contact with fellow industryrepresentatives and with other business, univer-sity, Cooperative Extension, and government

organizations.Essential to a producer's sound marketing

program is also a clear understanding of thefarm's financial situation at all times dUringthe annual production cycle. Updated farmfinancial records and the input of financialinformation in budget generators will help thegrower to cut overhead and improve efficiency ofproduction. Updated financial information andwell organized farm records are also helpful inthe loan application process, in assessment ofcrop losses by unexpected pest outbreaks, and inmaking timely production and financialdecisions to take advantage of potential invest-ment opportunities or unexpected marketwindows.

52 8001:1 Price

51 • Volume 700 _-...0 ::S-......... 50

600 §til....s::Q) ....u 49 -'-'Q) Q)u 500 §'1: 48p.. -047 400 >

46 300

J M M J s NMonth

FIgure 5. Average monthly price and volw:ne for tomatoes in Hawaii, 1986-1990.

10

14000a import

_ 12000 • local:E§ 10000r-l-§ 8000....

6000

4000'78 '80 '82 '84 '86 '88 '90

Year

FIgure 6. Hawaii tomato imports aDd local production, 1978-1990.

2000

l§

1000

j

•U.S. localImports into U.S.

J FMAMJ JASONDMonth

Figure 7. Monthly volume oftomato shipment. in the United States and imports, 1990.

11

REFERENCESAlvarado. B.. and J. T. Trumble. 1989. EI manejo

integrado de las plagas en el cultivo detomate en Sinaloa. CAADES. Sinaloa.Mexico.

Dangler. J. M.. and S. J. Locascio. 1990. Yield oftrickle-irrigated tomatoes as affected bytime of Nand K application. J. Amer. Soc.Hort. Sci. 115:585-589.

Darby. J. F. 1953. Recent developments in thecontrol of the major diseases of unstakedtomatoes grown on the sandy soils of southFlorida. Proc. Florida State Hort. Soc.66:103-107.

DeFrank. J. 1986. 1986 chemical weed controlgUide for tomatoes in Hawaii. Univ. HawaiiCoop. Ext. SeIV. HlTAHR Brief 54.

Dhillon. P. S .. and R. G. Brumfield. 1990.Greenhouse tomato production in New Jer-sey. New Jersey Agr. Exp. Sta. P-02131-1-90.

Fox. J. A. and F. Killbrew. 1992. Cercospora leafspot of greenhouse tomatoes. MississippiCoop. Ext. SeIV. Veg. Press 92: 1.

Garton. R. W.• and I. E. Widders. 1990. Nitrogenand phosphorus preconditioning. of small-plug seedlings influence processing tomatoproductivity. HortScience 25:655-657.

Harris. P. 1992. Controlling whiteflies ongreenhouse tomatoes. Mississippi Coop. Ext.SeIV. Veg. Press 91:12.

Hassell. R. 1991. Plug quality starts with seed.Amer. Veg. Grower 39(5): 10.

Hochmuth. G. J .. ed. 1988. Tomato productiongUide for Florida. Florida Coop. Ext. ServoCirc.98-C. .

Kretchman. D. 1990. Tomato disorders arepreventable. Amer. Veg. Grower 38(8):14-17.

Nihoul. P.• G. Van Impe. and T. Hance. 1991.Characterizing indices of damage to tomatoby the two-spotted spider mite to achievebiolOgical control. J. Hort. Sci. 66:643-648.

Sewake. K. T.. A H. Hara. W. T. Nishijima. and B.C. Bushe. 1990. Questions and answers aboutintegrated pest management. Univ. HawaiiCoop. Ext. SeIV. HlTAHR Brief 88.

Sheldrake. R. 1989. Tomato profits are in thebag. Amer. Veg. Grower 37(8):24. 26. 28.

Sorensen. H. B. 1955. Methods of determiningthe optimum stage of maturity for pickinggreen-wrap tomatoes. Texas Coop. Ext. SeIV.Bull. 820.

Wien. H. C. 1989. How temperature stress affectsfruit set. Amer. Veg. Grower 37(8):56-57.

12

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department ofAgriculture. Noel P. Kefford, Director and Dean, Cooperative Extension Service, College of Tropical Agriculture and Human Resources,University of Hawaii at Manoa, Honolulu, Hawaii 96822. An Equal Opportunity Employer providing programs and services to the citizens ofHawaii without regard to race, color, national origin, or sex.

RESEARCH EXTENSION SERIES 141--03193 (4.5M)