guide to the commercial production of muskmelon (cantaloupe

Guide to the CommercialProduction of Muskmelon(Cantaloupe) and Related Melons

Historical PerspectiveMuskmelons, often called can-

taloupes in the United States, are notcommonly grown here. True can-taloupes have deeply grooved fruitwith a hard, warty, or scaly rind andorange or green flesh. Muskmelons(Cucumis melo L. Reticulatus Group),on the other hand, possess a fruitrind that is netted. The muskmelon isa member of the Cucurbitaceae (cu-cumber) family, which also includescucumbers, watermelons, and honeydew, Persian, casaba, and crenshawmelons.

Evidence suggests that muskmel-ons were cultivated in Egypt as earlyas 2400 B.C. Little information exists,however, describing how the plantwas used in ancient times. A nativeof Middle Eastern countries, musk-melons spread slowly to Europe. Inthe fifteenth century, muskmelonsbecame popular in Spain and weresoon introduced to the New World.By the mid-1600s, muskmelons weregrown from Florida to New England.The modern muskmelon is derivedfrom the ‘Netted Gem,’ a highly net-ted cultivar introduced by the W.Altee Burpee Company in 1881.

In the United States, muskmelonproduction is concentrated in aridand semi-arid regions, but they aregrown in many states for local andinterstate sales. California accountsfor 70 percent of total U.S. produc-tion, followed by Texas and Arizona.Nutritionally, the muskmelon is muchhigher in vitamins A and C than thewhite-fleshed honey dew or wintermelons (casaba or crenshaw).

Flowers And PollinationMuskmelons produce two types of flowers—perfect flowers, having both

male and female parts, and staminate flowers, having only male parts. Perfectflowers upon pollination and fertilization will develop into the familiar fruits.Muskmelons set fruit in cycles where several fruit are set per plant in eachcycle. Fruit harvested from the first cycle of fruit set have the highest quality.

Muskmelons require bees for pollination. For greater yields and larger mel-ons, place one or two strong hives of honeybees per acre adjacent to fields ofmuskmelons. Hives can be removed after fruits are set. Application of pesti-cides should be delayed until evening when bee activity is low, as many pes-ticides are toxic to honeybees.

Planting RecommendationsSoil and fertility

Muskmelons grow best on well-drained, upland, silty, or (preferably) sandyloam soils with a pH level between 6.0 and 6.5. Melons planted into acidicsoils (pH less than 6.0) will have yellowed foliage and produce fewer perfectflowers. Beds should be 6 to 8 inches high to facilitate drainage. If you use acover crop, be sure to plow it under at least 1 month prior to planting.

Timely and appropriate applications of fertilizer can make a significant dif-ference in the quality and quantity of fruit and may promote earlier harvests.Collect soil samples from each area you intend to crop and have a soil analy-sis performed on each sample. Soil testing eliminates much of the guessworkinvolved in a fertilizer program. Be sure to apply lime several months prior toplanting. Contact your county Extension agent for information on how to col-lect a soil sample and for boxes used to submit samples.

Muskmelons produce twotypes of flowers:(A) Perfectflowers, having both maleand female parts, and (B)staminate flowers, havingonly male parts.

A

B

Note swelling at base of flower.This will developinto fruit.

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If a soil test is not performed,apply 40 to 50 pounds of nitrogenand phosphorus (P2O5), and 100 to120 pounds of potassium (K2O) peracre at planting. At layby, sidedresswith an additional 40 to 50 pounds ofnitrogen per acre.

SeedingMuskmelons may be planted by

direct seeding or by transplants afterall danger of frost has passed. Direct-seeded melons should be sownwhen the soil temperature is above65°F, but the optimum temperaturerange for germination is between 70°and 95°F. Use fungicide-treated seed,as muskmelons are sensitive todamping off, especially under cool,wet, soil conditions. Sow seed at adepth of 1⁄2 to 1 inch. Seeding willrequire 2 to 4 pounds of seed peracre (16,000 to 20,000 seeds perpound), unless a precision-type seed-er is being used.

TransplantingThe use of transplants can reduce

seed cost compared to direct-seedingand result in earlier production, espe-cially when used with polyethylenemulch. Seeding for transplant pro-duction should be done 2 to 4 weeksprior to date of transplanting.

Spacing and planting datesWhether direct-seeding or trans-

planting, space rows 5 to 6 feet apartwith an in-row spacing of 18 to 24inches. This will result in stands of3,600 to 5,500 plants per acre.Traditionally, in-row spacings up to36 inches have been used inAlabama, but modern hybrids andopen-pollinated lines perform well atcloser in-row spacings, resulting inhigher yields and increased uniformi-ty. Sow or transplant 20 March to 15April in South Alabama, 10 April to30 April in Central Alabama, and 20April to 15 May in North Alabama.Provide muskmelons with at least 1inch of water per acre per week.

VarietiesMuskmelons generally are classi-

fied as eastern-types or western ship-ping-types.

• Eastern-type characteristics:Round to oval, usually sutured, andnetted; not intended for long-distanceshipping.

• Western shipping-type character-istics: Round to slightly oval, suture-less, very well netted, with firm flesh.

Contact your county Extensionagent for the latest edition of theSpring Vegetable Variety Trials fromthe Alabama Agricultural ExperimentStation, Auburn University. In the re-port you will find information on theperformance of selected muskmelonvarieties trialed in several locationsthroughout Alabama. As there are alarge number of commercial varietiesavailable, only those well adapted toAlabama should be grown. It is advis-able to grow a small trial plot of sev-eral varieties each year to determinewhich are best suited to your growingconditions.

Many commercial muskmelon va-rieties are available with resistance toone or more diseases, notablyFusarium wilt, downy mildew, andpowdery mildew. You should choosevarieties that are resistant to diseasesthat are prevalent in your growingarea. In addition, many muskmelonvarieties are sensitive to air pollution(ozone, sulfur dioxide, and sulfur tri-oxide), as well as to applied sulfur(used for disease control). This sensi-tivity is cultivar dependent and maybe included in descriptions of vari-eties found in variety trial reports.

The following list of other types ofmelons are considered to be specialtymelons in the United States, but theyhave similar cultural requirements tomuskmelons. Demand for these typesof melons tends to be regional butmay offer a potential for smallergrowers or those who specialize inniche markets. Before consideringgrowing any of these melons, ex-plore the market potential of them inyour region. Available commercialvarieties are listed following the de-scriptions of the various types of mel-ons that follow.

Honey dewSmooth, greenish white rind, turn-

ing creamy when ripe. Light green,sweet flesh with some orange fleshedvarieties available. Fruit 7 x 71⁄2 inch-es, 5 to 6 pounds. Varieties:‘Earlidew,’ ‘Honey Dew Green Flesh,’‘Tam Dew,’ ‘Honey Dew Orange’ (or-ange flesh).

CasabaA non-slip (see Harvesting sec-

tion), late maturing, corrugated yel-low, sometimes greenish yellow rind,not netted or ribbed, with white,spicy, sweet, and tender flesh. Fruitacorn-shaped, 8 x 7 inches, 7 to 8pounds. Varieties: ‘Casaba GoldenBeauty,’ ‘Casaba Sungold’ (earliest ofthe casaba types), ‘Marygold.’

CrenshawLarge, late maturing, yellow and

green corrugated, rough rind withoutnetting. Pinkish orange, sweet, tenderflesh with distinctive flavor. Fruit iselongated with a flattened stem end(elongated acorn-shape), 9 x 7 inch-es, 7 to 10 pounds. Varieties:‘Crenshaw,’ ‘Honeyshaw’ (early),‘Early Hybrid Crenshaw,’ ‘CrenshawBlanco,’ ‘Golden Crenshaw.’

CanaryLate maturing, bright yellow corru-

gated rind. Flesh is pale green towhite with a pale orange seed cavity;it has a sweet and distinctive flavor.Fruit is oval, similar to crenshaw, 8 x6 inches, 6 to 7 pounds. Varieties:‘Sweet Yellow Canary,’ ‘Tenerife.’

Guide To Commercial Production Of Muskmelon 3

Santa ClausVery similar to Canary type except

rind is mottled green and yellow. Thename is derived from the long keep-ing qualities of this melon. ‘SantaClaus’ is also the variety name.

CharentaisA popular European melon, also

called ‘Chaca,’ ‘French,’ or ‘Italianmelon.’ Smooth or slightly netted,gray-green rind with dark green,slightly furrowed sutures. Deep or-ange, firm, sweet flesh. Fruit is slight-ly elongated but mostly globe shaped31⁄2 to 4 inches and 11⁄2 to 2 pounds.Varieties: ‘Acor F1’ and ‘Alienor F1’(both monoecious and resistant toFusarium races 0, 1, and 2),‘Charentais Improved,’ ‘Ido,’ ‘OvalChaca,’ ‘Red Queen,’ ‘Panchito’ (net-ted rind).

MediterraneanFruits have a green rind with slight

netting with no sutures, ripening toyellow gold with some green splotch-es. Flesh is soft and white with atouch of pink around the seed cavitywhen ripe. Fruit oval 61⁄2 x 71⁄2 inch-es, 5 to 51⁄2 pounds. Variety:‘Casablanca.’

PersianVery late maturity, green rind with

slight tan cracks or sparse netting.Orange-pink, sweet, firm flesh. Fruitis round 71⁄2 x 8 inches, 5 to 6pounds. Varieties: ‘Persian Medium,’‘Crete’ (crisp flesh, excellent forfrozen melon balls).

OgenMelons are netted with no suture,

green, sweet, and have highly aro-matic flesh; the rind turns golden yel-low as the melon matures. Thismelon will slip like muskmelon andresists splitting during periods ofrainy weather. Fruit is round, 3 to 5pounds. Varieties: ‘Galia,’ ‘Gallicum,’‘Haogen.’

RochetGreen rind melons are slightly net-

ted and have greenish white, sweet,and aromatic flesh. Oval. Varieties:‘Solo’ (4 to 5 pounds); ‘Toledo’ (alsocalled frog skin type because of thegreenish yellow rind with dark greenblotches); ‘Verdol F1’ (dark green skinslightly netted and crisp, white, sweetflesh (resistant to Fusarium races 0, 1,and 2; also referred to as Spanish type).

Chinese ‘Hami’ melonHami is the generic Chinese word

for a group of crisp-fleshed “winter”melons. Hami melons may have ei-ther red-pink, salmon, white, orgreen flesh. One group is slightlylonger than a football but smaller indiameter (resembles Rochet type).These have yellow or yellow andgreen rind, usually slightly netted.The flesh is crisp and very sweet.These melons may be stored for sev-eral weeks to a few months with littlequality loss. In China, these are evenallowed to dry partially for use lateinto the fall and early winter (similarto Santa Claus melon). These appearto also be particularly suited forfrozen melon balls.

Oval, 6 to 9 pounds. Varieties:‘New Century,’ ‘Red-Pink Hami,’‘Tiger-Skin Hami.’ Round typeChinese Hami variety: ‘Snow Charm’(better adapted to cooler areas). Fruitcan reach very large size (10 to 12pounds but more commonly 3 to 4pounds), globe shaped, white to lightyellow, smooth rind, light orange topink flesh, crisp texture, sweet, ex-cellent frozen.

Japanese melonsThese melons are extremely well

netted, with green rind; fruit is non-slipping when ripe and very sweet.Round or slightly oval, about 7 x 8inches, 3 to 4 pounds. Varieties:‘Tokyo King’ (the classic Japanesetype—white fleshed); ‘Emerald Jewel’(green fleshed); ‘Emerald Pearl’(green crunchy sweet flesh); ‘Ginryu’and ‘Zuikoh’ (both have sweet, greenflesh, excellent frozen); ‘Amur’(Persian type with light green flesh);

‘True Arus’ (yellowish green), aro-matic flesh; ‘Theresa’ (juicy greenflesh); ‘Toho’ (green flesh).

Mulching And DripIrrigation

Polyethylene (black plastic) mulchcan offer several advantages to grow-ers. Black plastic mulch increases thesoil temperature earlier in the grow-ing season, conserves moisture, andreduces several common problems:soil compaction and crusting, groundrot of fruit, fertilizer leaching, drown-ing of crops, evaporation, and com-petition from weeds. These benefitspromote increased quality and quan-tity of fruit yields and result in earlieryields, especially when used in com-bination with transplants. The use oftransplants with plastic mulch gener-ally results in harvests that begin 7 to14 days earlier as compared to bareground production. Although usingmulch will increase production costs,those costs should be offset by in-creased profits from earlier and largeryields. Drip irrigation systems mustbe used with plastic mulch. Be sureto offset the drip tape 3 to 4 inchesfrom the center of the bed, 2 to 3inches deep.

Row Covers AndWindbreaks

Spunbonded polyester and perfo-rated polyethylene row covers maybe used for 4 to 8 weeks immediatelyafter transplanting to further enhanceearliness. Covers should be removedwhen plants begin to flower to allowproper pollination. Row covers maybe replaced after pollination is com-pleted (after 3 to 5 fruits per planthave been pollinated) to further en-hance earliness.

Windbreaks are recommendedwhere wind erosion is likely.Temporary windbreaks of winterwheat or rye prevent sandblasting ofyoung seedlings and whipping ofvines as plants begin to run. As withrow covers, windbreaks also provideadditional heat accumulation in thespring.


Weed ControlA weed control program for any

crop begins before planting, but thisis especially true for muskmelons be-cause only a handful of herbicidesare registered for use on this crop. Ifpossible, select an area for plantingwhere weed populations are low andthere are no perennial weeds such asnutsedge, bermudagrass, or vines.Perennial weeds generally requirepowerful herbicides or fumigation tocontrol. Primary tillage includingmoldboard plowing, disking, andbedding are considered weed controlmethods, since these operations gen-erally kill most emerged weeds. It iscritical to start with a clean field be-fore planting the crop, because anyemerged weed will have a significantadvantage over the young muskmel-on seedlings in competing for water,fertilizer, and sunlight.

Cultivation can provide effectiveweed control between rows as longas the cultivator can be used withoutdamaging the crop. If plastic mulch isused, between-row cultivation maynot be practical or may be limitedbecause of potential damage to theplastic. Soil-active herbicides can beapplied before mulching, but the ef-fectiveness of post-emergence treat-ments may be limited because ofplastic mulch. Hand weeding be-tween rows may be a viable optionin small acreage situations. Contactyour county Extension agent for rec-ommended herbicides registered foruse on muskmelons.

Insect ControlSeveral insect pests attack musk-

melon, and growers should be pre-pared to make management deci-sions regarding their control. Some of these pests may cause problemsevery year, and others may only beoccasional pests. Contact your countyExtension agent for recommended in-secticides registered for use onmuskmelons. Use insecticides onlywhen necessary to conserve bee pol-linators and the parasites and preda-tors of insect pests that may normallyinhabit melon fields or adjacentareas. If an insecticide application isneeded, apply late in the day whenbees and natural enemies are leastactive.

WirewormsWireworms are the soil-inhabiting

larvae of click beetles. They have acylindrical, hard-bodied, wire-like ap-pearance. They are shiny, brownishyellow, and 1⁄2 to 11⁄2 inches long.Wireworm damage usually occursjust after transplanting or seed emer-gence. Larvae feed on the roots andstems of young plants, causing plantsto become stunted and to wilt. Stemsmay have shallow, oval feeding scarsor deep, circular holes where wire-worms have entered. Wireworms aremost likely to be a problem whenmelons are planted into “new” land(for example, pasture that containedgrasses) or following plantings of sodor small grains. Damage is most oftenobserved under cool, moist soil con-ditions and in heavier soils. There isno “rescue treatment” for wirewormdamage. If a wireworm infestation isdetected or suspected, a recommend-ed pre-plant soil insecticide treatmentis warranted.

Whitefringed beetlesWhitefringed beetles are named

for the white stripe on both sides ofthe adults. As with wireworms, thesoil-inhabiting larvae cause the mostserious damage by feeding on theroots of young plants. Larvae are palewhite to yellow, legless grubs with adark head capsule ranging in sizefrom about 1⁄16 inch to almost 1⁄2 inchlong. Severe whitefringed beetle in-festations can result in poor plantstands because of the destruction ofthe root system by the larvae. As withwireworms, whitefringed beetles aremost likely to be a problem whenmelons are planted into new land.But whitefringed beetles prefer awide variety of broadleaf weeds (par-ticularly legumes) over grasses. If awhitefringed beetle infestation exists,the grubs can be detected in thespring before planting by turningover the soil with a spade. If grubsare observed, a recommended pre-plant soil insecticide treatment is war-ranted. There is no available controlpost-planting for whitefringe beetle.

Cucumber beetlesTwo species of cucumber bee-

tles—striped and spotted—may infestmuskmelon. Both species are about1⁄5 inch long with a yellow-greenbackground color. The striped cu-cumber beetle has three black stripesalong the length of the body, and thespotted cucumber beetle has 12 blackspots on its back. In the southernstates, cucumber beetles may hiber-nate during cold winters, or they mayremain semi-active during warmerwinters. The beetles begin feeding onalternate weed hosts in the earlyspring and can move into spring-planted melons just after seed emer-gence or transplanting. Cucumberbeetle larvae feed on roots and stemsand may cause stunting of smallplants. When populations are high,the cucumber beetle adults feed onfoliage and can stunt or kill seedlingsor young transplants. Beetles alsofeed on melon rind later in the sea-son, causing cosmetic damage thatreduces the number of marketablefruit.


Cucumber beetles also serve asvectors for the transmission of a bac-terium that causes bacterial wilt, a serious disease of cucurbits. The bac-terium overwinters in the digestivetract of the beetles and can be trans-mitted to susceptible plants the fol-lowing spring when the beetles be-come active. Transmission to plantsoccurs through wounds on leavescreated by feeding. Once infected,plants become wilted and die. Theonly way to avoid bacterial wilt is toprevent the beetles from feeding onthe plant. Research at AuburnUniversity has shown that the firstfew weeks after beetles colonize theyoung cucurbit plants is the mostcritical period for bacterial wilt infec-tion. Therefore, this is the most im-portant time to target cucumber bee-tle controls.

There are two options for cucum-ber beetle control. If the area has ahistory of cucumber beetle and bac-terial wilt problems, growers may optto use the systemic soil insecticidecarbofuran at planting. Research inother states has shown that carbofu-ran may provide up to 4 weeks ofbeetle control. The other control op-tion is to monitor plants regularly,particularly during the susceptibleearly season stage, and to apply fo-liar insecticides if beetles are present.Pyrethroid insecticides will give thelongest residual control (about 7days). Foliar insecticides are not usu-ally needed after beetle populationsdecline and plants mature.

A new type of insecticide calledAdios is now available for cucumberbeetle control. Adios contains a bee-tle feeding stimulant along with theinsecticide carbaryl. Beetles taste thefeeding stimulant, feed compulsivelyon the insecticide, and die. Adios is afairly effective alternative to standardpyrethroid insecticides for control ofcucumber beetles. Another advantageof Adios over standard foliar insecti-cides is that Adios is not harmful tobees, which are important for polli-nation.

PicklewormThe pickleworm is one of the

most damaging insect pests of cucur-bits. This pest does not overwinternorth of southern Florida, but theadult moths migrate into the northernstates as the growing season pro-gresses. Pickleworm moths are small,about 1⁄2 inch long, and easily recog-nizable by the wide, yellowish brownband on the outer wing margins. Thebody is also yellow-brown, with apurplish tinge. The tip of the ab-domen has a prominent roundedbrush of long hair-like scales. Theclosely related melonworm moth (nota serious pest) is similar in appear-ance, but the body behind the wingsis silvery white rather than yellow-brown, and the band around thewing margins is narrower than that ofthe pickleworm.

Pickleworm moths are night flyers,rarely seen during the day. Femaleslay egg clusters on tender buds andnew leaves and sometimes on thefruit. After hatching, young larvae de-velop inside the buds, blossoms, andleaf terminals. Older larvae are capa-ble of moving to the fruit where theyenter and complete development.Damage from a single larvae boringinside a melon will make the fruitunmarketable. The small larvae arepale green with many black spots ontheir upper surface; older larvae are a green-copper color except for thebrown head and brown area just be-hind the head.

Management of pickleworm withinsecticides can be difficult, becausethe larvae are almost always in pro-tected locations on or in the plant it-self. The best management scheme isto monitor plants weekly beginningwhen the first developing leaf budsand terminals are formed. If present,young pickleworm larvae can be de-tected by pulling apart the leaf termi-nals or buds. Although larvae mayalso be found in flower buds, the

majority will be located in the devel-oping leaf tissue. Newly hatched lar-vae are only about 1⁄8 inch long andblend in with the green plant tissue,but they can be detected with a bit ofpractice (a hand lens helps). Larvaltreatment thresholds have not beendeveloped for pickleworm; therefore,the current recommendation is tobegin a weekly spray program with arecommended insecticide if any lar-vae are found on the plants. Growerswho are not willing to monitor plantsfor signs of pickleworm usually begina preventive spray program when theflower buds first begin to form. Asuccessful cultural management strat-egy for pickleworm is early plantingand harvest. As pickleworms are mi-gratory, large populations do not de-velop until later in the season. This isparticularly the case in central andnorth Alabama.

Squash vine borerThis insect is usually a greater

problem on squash and pumpkinsthan on muskmelon, but melons, par-ticularly in the home garden, cansometimes be attacked. The adult is a“clearwing moth,” and actually looksmore like a wasp. The front wingsare covered with metallic, shining,olive brown scales, but the hindwings are transparent. The abdomenis ringed with red, black, and copper,and the moth flies swiftly and noisilyabout the plants in the daytime. Eggsare laid on stems near the base of theplant. Upon hatching, the larvae boreinto the stems and tunnel along, eat-ing the inner tissue. Larvae are awhitish cream color with a brownishhead.


As with pickleworm, control withinsecticides is not greatly effective,because the larvae are protected in-side the stems. Fortunately, this in-sect is not usually a serious problemin commercial melon production.Commercial growers with a historyof borer problems usually watch formoth activity around the plants, thenbegin a weekly spray program with arecommended insecticide if moth ac-tivity is observed. A fairly effectivehome-garden management strategy isto check the base of the plant stemsfor holes or excrement, which indi-cates borer infestation. If infested,stems may be slit lengthwise at thepoint of attack and the larvae de-stroyed. The stems may then be cov-ered with moist earth to encouragedevelopment of roots. To reduce in-jury the following year, all vinesshould be destroyed soon after thefinal harvest. The soil should beraked or disked in the fall and turnedunder deeply in the spring to preventthe emergence of adults from co-coons.

Aphids and mitesAphids are small, soft-bodied in-

sects that feed by sucking fluid fromthe plant. Infestations begin whenwinged adults fly into fields fromweeds or other crops. Later, coloniesof wingless aphids, which feed nearthe plant base or on the undersidesof young leaves, are produced on theplants. This feeding results in cup-ping of the leaves. When plants areheavily infested, leaf distortion andstunting are common, and fruit setmay be reduced. Upper leaf surfacesmay be covered with “honey dew,” asubstance secreted by the aphids.The honey dew also causes stickinesson fruit surfaces and is associatedwith the growth of black, sooty moldfungus.

In addition to feeding damage,aphids can transmit plant viruses (forexample, cucumber mosaic virus, wa-termelon mosaic virus; see section onmelon diseases for more informa-tion). Control of aphids and aphid-borne viruses are difficult with insec-ticides. In fact, application of someinsecticides like the pyrethroids de-stroys the aphids’ natural enemiesand results in increased aphid popu-lations. Therefore, use of pyrethroidsshould be avoided if possible. Over-fertilization with nitrogen can also in-crease aphid numbers. Reflectivemulches can be used to delay colo-nization by winged aphids and sub-sequent transmission of viruses.Control of weeds within the fieldalong field borders is also of value inreducing the potential for aphid in-festation. Weekly application of high-ly refined oils (for example, stylet oil)using high spray volume and pres-sure has been shown to reduceaphid-transmitted virus infection byas much as 90 percent.

Mites are actually arthropods moreclosely related to spiders than insects.They are tiny (about 1⁄50 inch long)and pale yellow or red in color. Ahand lens is necessary to see themclearly. They are primarily found onthe undersides of leaves, where theysuck plant sap and, in hot, dryweather, can defoliate vines in a few

weeks. Defoliated plants yield small,poor quality fruit. Mite infestationsusually occur along the edge of afield, frequently next to a gravel ordirt road or a grassy area. Dusty con-ditions favor mite development. Asmite populations increase, infestedleaves turn yellow. The undersides ofaffected leaves appear tan or yellowand have a crusty texture. Mites canbe identified by shaking leaves ontoa sheet of white paper and watchingfor moving specks or by observingleaves with a hand lens. As withaphids, pyrethroid and carbamate in-secticides may actually increase mitepopulations by destroying natural en-emies of mites. Because mite infesta-tions usually begin on the fieldedges, these areas should be inspect-ed regularly, particularly during peri-ods of hot, dry weather. If a mite in-festation is found, the infested borderareas may be spot treated with a rec-ommended miticide, followed by an-other treatment within 5 days.Continue to monitor the affected areato ensure that the mite infestationdoes not spread.

Control Of DiseasesAnd Nematodes

As with any insect or weed prob-lem, always confirm your disease di-agnosis. Consult your countyExtension agent for recommendedfungicides registered for use onmuskmelons.

Figure 1. Muskmelon infected with bac-terial wilt.


Bacterial wiltBacterial wilt, caused by the bac-

terium Erwinia tracheiphila, is a de-structive disease of plants in the cu-cumber family. Although bacterialwilt is most common on muskmelonand cucumber, it can also infectsquash, pumpkins, and a number ofwild cucurbit plants. Watermelonsand most gourds are highly resistantto the disease.

Bacterial wilt is characterized ini-tially by wilting and drying of indi-vidual leaves. Within a day or twothe wilting symptoms spread toleaves up and down a runner (Figure1). The bacteria spread from infectedrunners to the main stem and then toother runners within the plant. Twodiagnostic techniques can be used toidentify bacterial wilt in the field:

1. Cut a wilted stem near thecrown and squeeze sap from the cutstem, watching for a white exudate

from the vascular bundles. Thentouch a clean knife blade to the cutsurface and slowly withdraw theblade from the stem. Watch for awhite ooze that strings out in a finethread between the newly cut stemsurface and the knife blade.

2. Take two recently cut stem sec-tions from near the crown of a re-cently wilted vine. Squeeze sap fromthe cut stem ends then press the twoends together. Continue to squeeze,then slowly draw the two sectionsapart. The presence of a thin, sticky,white strand or strands between thetwo sections is a positive test for bac-terial wilt (Figure 2).

Positive test results are easier to

Table 1. Recommended Control Strategies For Common Muskmelon Diseases.Follow

Use Balanced Scout Apply Allow for Destroy allResistant Fertility for Recommended Control Good air CropVarietiesa Programb Signs Fungicidec Weeds Movement Residue Rotationd

Powdery Mildew √ √ √ √ √ √ √ √Downy Mildew √ √ √ √ √ √ √ √Anthracnose √ √ √ √ √ √ √ √Gummy Stem

Blight √ √ √ √ √ √ √AlternariaLeaf Spot √ √ √ √ √ √ √ √Fusarium Wilt √ √ √ √aAlways use certified, disease-free transplants or seed.bFollowing a balanced fertility program includes conducting a soil test and following its recommendations.cAlways be sure to get good spray coverage, especially on the lower leaf surface. Apply fungicides on a timely basis.dRotate with non-cucurbit crops for a minimum of 2 years; minimum of 5 years with varieties resistant to Fusarium wilt. These diseases can becarried over from year to year on cucurbit weeds or muskmelon volunteers; thus, it is important to control weeds during rotations.

obtain for cucumber and for somesquash than for muskmelon. Becausethe bacteria are spread by cucumberbeetles, the best and most logicalcontrol is management of the insect

vector. Consult the Insect Controlsection above for detailed informa-tion on control of cucumber beetles.At the first sign of disease in smallplantings, wilted plants should besprayed with a recommended insecti-cide and removed.

Powdery mildewPowdery mildew, caused by the

fungus Erysiphe cichoracearum, af-fects muskmelon, cucumber, pump-kin, and squash. The fungus pro-duces a white to gray powderygrowth on infected petioles, stems,and the upper surface of leaves(Figure 3). Crown leaves are usuallyinfected first. Severely infected leavesbecome yellow and then turn dry,brown, and papery. Infected plantsmay be stunted. The loss of foliagewill increase the number of sun-burned fruit. Although fruit are notaffected directly, severe leaf infectionusually results in reduced sugar con-tent in fruit.

Figure 2. Positive bacterial ooze test forbacterial wilt.

Figure 3. Powdery white appearance ofpowdery mildew on upper leaf surface ofmuskmelon.

Figure 4. Yellow spots of downy mildewon upper leaf surface of muskmelon.


The fungus can overwinter oncrop debris and, more commonly, onweeds. Spores of the fungus can beblown long distances on wind cur-rents. Infected transplants can be an-other source of the disease.Development of powdery mildew isfavored by high temperatures (80°F)and high humidity (50 to 90 percent).Development is also favored by lushor poor plant growth (resulting fromimproper fertility), low light intensity,and heavy dews. When conditionsare favorable, an entire field can be-come severely infected within aweek. Powdery mildew, unlike mostfungal diseases, can be a problemduring periods of dry weather. SeeTable 1 for recommended controlstrategies.

Downy mildewDowny mildew, caused by the

fungus Pseudoperonospora cubensis,affects muskmelon and cucumber.The disease can reduce yield andfruit quality. If plants are infectedearly in the season, downy mildewcan kill plants. The fungus causes ir-regularly shaped, yellowish to brownspots on the upper leaf surface(Figure 4). Spots are often angularand are restricted by the small veinsof the leaf. Under moist, humid con-ditions, a fluffy, purplish to gray fun-gal growth appears on the undersideof the leaf corresponding to the leafspots above. As the spots enlarge, theleaves turn yellow and eventuallydie. Infected leaves that die remainerect while the edges of the leafblade curl inward. Severe infectionsresult in defoliation, stunting ofplants, and poor fruit development.The disease usually affects olderleaves first and progresses outward.

Temperatures between 60° and70°F, heavy dews, or frequent rainsfavor development. The fungus canoverwinter in an area or can be intro-duced on wind currents from consid-erable distances. See Table 1 for rec-ommended control strategies.

AnthracnoseAnthracnose, caused by the fungus

Colletotrichum lagenarium, can be adestructive disease of muskmelonsduring warm, wet growing seasons.The disease also attacks watermelon,cucumber, and gourds.

All aboveground plant parts aresusceptible to infection, and plantscan become infected at any stage indevelopment. Older leaves first showsmall, water-soaked or yellowishareas that enlarge rapidly and turntan to reddish brown (most cucur-bits) or black (watermelon). Spots areoften circular to angular. Later, spotsmay merge, blighting large sectionsof the leaf. These areas become dryand tear away, typically giving the fo-liage a ragged appearance. Often theleaves at the center of a plant are at-tacked first, leaving stems and run-ners bare. Tan to black, elongated,slightly sunken streaks (cankers)form on petioles and stems that cangirdle the vine, causing death of thetissue beyond the lesion.

Fruit, if infected early, may turnblack, shrivel, and die. Round, water-soaked spots, 1⁄4 to 21⁄2 inches in di-ameter, develop on the older fruit.Spots turn a dark green to brownwith age and may become sunken.Under wet conditions, pinkish col-ored spore masses can be seen ooz-ing out of the sunken spots.

The fungus overwinters in debrisfrom previous host crops, in seed, orin weeds of the cucurbit family.

Warm (75°F), wet conditions (fre-quent rains, poor drainage) favorrapid development and spread of thedisease. Anthracnose can appear any-time during the season, but mostdamage occurs late in the seasonafter the fruit is set. At least threeraces of Colletotrichum have been re-ported. See Table 1 for recommend-ed control strategies.

Gummy stem bightGummy stem blight, caused by the

fungus Mycosphaerella melonis, is acommon disease of muskmelon, wa-termelon, and cucumber. Symptomsfirst appear as grayish green, circularspots between the veins in the lobesof leaves. Spots turn a dark brown toblack with age. The leaf spot stagecan be confused with anthracnose;however, gummy stem lesions aredarker with target-like or zonate pat-terns with less deterioration of theleaf tissue. Spread of the disease be-gins in the center of the plant andspreads outward. Lesions developfirst on the vines at the nodes andelongate into water-soaked streaksthat become pale brown to gray withtime (Figure 5). Stem tissue oftencracks and a characteristic gummyooze exudes from the wound.Infected vines and occasionally entireplants die. The disease, unlike an-thracnose, does not attack fruit.

Although the fungi that causegummy stem blight and anthracnoseare two completely different organ-isms, their spread and their controlare very similar. Refer to the sectionon anthracnose for information onthe environmental conditions thatfavor their development. See Table 1for recommended control strategies.

Figure 5. Gummy stem blight lesion oncucurbit vine.


Alternaria Leaf SpotAlternaria leaf spot, caused by the

fungus Alternaria cucumerina, af-fects muskmelon and cucumber aswell as other cucurbits. The diseasecauses damage by defoliating thevines and reducing fruit yield, size,and quality. Symptoms first appearon the upper leaf surface as small,circular, tan spots with white centers.Spots enlarge up to 1⁄2 inch in diame-ter, turn light brown, and form aslight depression. Spots on the upperleaf surface often have dark concen-tric rings within the lesions. Spotsmerge and defoliation occurs, begin-ning with the crown leaves.

Severe defoliation can increase thenumber of fruit damaged by sunburn.Symptoms on fruit appear as circular,sunken spots. Spots may be coveredwith a dark olive to green to blackmold. Fruit turn brown and shrink,later becoming black and mummi-fied. The rot is often associated withsunscald or over ripeness.

The fungus can overwinter in oron seed, in cucurbit weeds, and ininfested plant debris. Spores of thefungus can be spread by wind andrain. The disease is favored by warm,wet (dews, rains, or overhead irriga-tion) conditions. Weak plants aremost susceptible to the disease. SeeTable 1 for recommended controlstrategies.

Fusarium wiltFusarium wilt, caused by the fun-

gus Fusarium oxysporum f. sp. melo-nis, only infects muskmelon, cren-shaw melon, and honey dew melon.Plants infected early in their develop-ment often damp-off at the soil line.Older plants first exhibit temporarywilting during the heat of middayand generally die within a few days.Wilt symptoms develop in one ormore lateral vines, starting at the tip.

Figure 6. Typical mosaic virus symptomon muskmelon leaf.

When the epidermis and corticaltissue (bark) on a section of the mainstem is cut back slightly above thesoil line, a light brown discolorationof the vascular tissue (area just be-neath the epidermis) will be evident.Brown streaks may also develop ex-ternally on the runner at the soil lineand extend for some distance up thevine. Streaks are at first light brown,turning yellowish tan, then darkbrown with age. This symptom is di-agnostic for the disease. A white topink fungal growth may develop oninfected stems during wet weather.

The causal fungus survives fromseason to season in old infectedvines, on seed, or in soil. The funguscan live on dead plant material or onthe roots and stems of other plantssuch as tomatoes and several weeds.Infection occurs through the root tip,natural openings, or wounds (for ex-ample, nematode feeding sites), andeventually the fungus invades thewater conducting vessels. Pluggingof the vessels leads to reduced watermovement followed by wilt anddeath. Disease incidence and severityare increased during warm, dryweather. See Table 1 for recommend-ed control strategies.

Fusarium fruit rotFusarium fruit rot of muskmelon

is caused by the soil-borne fungusFusarium roseum. Usually ripe fruitare affected. Lesions may occur any-where on the fruit but are frequentlyfound at the stem end. Tan coloredspots that are about 1 inch in diame-ter develop on fruit. Internal decaymay be shallow or may extend intothe seed cavity. The rotted tissue iswhite to rose colored, dry, andspongy. This tissue can easily be sep-arated from the surrounding healthytissue. A white mold develops on thesurface of infected fruit during wetconditions and in storage.

This fungus is common in soil. Awound caused by insect or mechani-cal damage is necessary for infection.The disease is more common in thin-skinned varieties. Further infectionscan occur during harvesting if knivesbecome contaminated through con-tact with infected plants or infestedsoil. Control consists of managementpractices that reduce fruit injury, pre-vent fruit contact with the soil sur-face, or reduce moisture on the fruitsurface.

Mosaic virusesThree viruses found commonly in

muskmelons are cucumber mosaicvirus (CMV), squash mosaic virus(SqMV), and watermelon mosaicvirus (WMV). These viruses differ intheir host range, method of transmis-sion, and in how they overwinter.Symptoms produced by these virusesare similar, making field identificationimpossible. Special laboratory testingis required for positive identification.

CMV attacks more than 40 familiesof plants worldwide, including allvine crops. Strains of CMV differ intheir host range, symptoms, andmethod of transmission. Cucurbits are susceptible at any stage ofgrowth. When plants become infect-ed in the six- to eight-leaf stage,symptoms first appear on theyoungest, still expanding leaves. A mosaic pattern develops (healthydark green leaf tissue intermingledwith light green and yellow tissue(Figure 6). Leaves are often distorted,crinkled, curled, and stunted. Vinesmay appear bunchy because of theshortening of the internodes.


Figure 7. Root galls produced by root-knot nematodes.

In severe cases, older leaves maydie. Typical mosaic symptoms devel-op only on actively growing leaves.When a plant becomes infected atmidseason, previous growth remainsnormal and produces healthy fruit.Few fruit set on plants that are infect-ed early in the growing season. Fruitthat do set, however, are often ofpoor quality and may be mottledgreen and yellow or have dark greenwarts.

CMV survives in almost 800species of plants, including manyweeds found in Alabama. Theseweeds often act as reservoir hosts al-lowing CMV to overwinter. The viruscan be spread and transmitted bymore than 60 species of aphids.Transmission is in a non-persistentmanner, meaning that the aphidsonly need to feed on a CMV-infectedplant for only a few seconds to pickup the virus.

SqMV infects most cucurbits but israrely a problem in watermelon. Onmuskmelon, SqMV causes yellowspotting, a green and yellow mosaic,and green vein-banding on theleaves. A few leaves may becomemalformed with veins protruding be-yond the leaf margin. The virus canoverwinter in weeds, seed, and incucumber beetles. Cucumber beetlesare efficient vectors of SqMV, spread-ing the virus during feeding.

WMV affects all cucurbits and afew others including English peasand alfalfa. Symptoms vary depend-ing on the host and plant age at thetime of infection. Symptoms on mostcucurbits may include stunting, leafmalformation, yellowing or lightgreen mottling, and marginal chloro-sis. Plants that are infected whenthey are young produce few mar-ketable fruit. Fruit that are producedmay be dwarfed, mottled, or spotted.

WMV overwinters in seed or in in-fected weeds. In spring, the virus canbe spread by many species of aphidsin a non-persistent manner. Laterplantings risk greater damage as dis-ease incidence and aphid popula-tions increase during the growingseason.

Control of mosaic viruses in cucur-bits begins with eradication of bien-nial and perennial weeds and wildreservoir hosts in and around gar-dens and fields. Applications of in-secticides to prevent the buildup oflarge aphid and cucumber beetlepopulations, as well as other insects,will reduce virus incidence andspread. When possible, plant certifiedvirus-free seed or transplants. Isolatelater plantings far from earlier set-tings, especially if virus incidencewas high. Removing infected plantswhen symptoms first appear may re-duce or delay spread of the disease.

Root-knot nematodesRoot-knot nematodes,

Meloidogyne spp., can attack cucur-bits as well as more than 2,000 otherspecies. When root-knot nematodepopulations are high, plants are oftenstunted and may wilt during dry con-ditions or during the hottest part ofthe day. Nematodes damage the rootsystem by disrupting the flow ofwater and nutrients and by causingwounds that give access to diseasessuch as Fusarium wilt. Detectingroot-knot nematodes in the field isdone easily by examining roots ofsymptomatic plants. The nematodescause knots or galls (Figure 7) to de-velop on both large and small roots;knots range in size from the head ofa pin to 1 inch in diameter.

Root-knot nematodes have a widehost range that includes many culti-vated crops as well as many weedspecies. The nematodes survive inthe soil from year to year and be-come active as soil temperatures in-crease in the spring. The most effec-tive control of root-knot nematodes isthrough the use of resistant varieties.Rotation with grasses and other ne-matode-suppressive crops (seeCircular ANR-856, “NematodeSuppressive Crops”) or clean fallow-ing during the off-season will reducenematode populations. Soil fumiga-tion is an effective means of reducingdamaging population levels tem-porarily (one growing season). Soilsolarization has also been shown tobe effective in reducing nematodepopulations when environmentalconditions are favorable for its use(See Circular ANR-30, “NematodeControl in the Home Garden,”Circular ANR-500A, “Alabama PestManagement Handbook—Volume 1,”and Circular ANR-713, “Soil Solari-zation for the Control of Nematodesand Soil-borne Diseases”).


HarvestingMuskmelons are harvested accord-

ing to the degree of stem slip, whichis when the stem begins to separatefrom the melon. Growers producingmelons for local sale can harvest themelons at full slip (when the fruit iscompletely separated from the vine).At this point, the fruit has reachedfull maturity and peak flavor, but willsoften too quickly for shipping. Forshipping, it is best to harvest whenthe muskmelons begin to slip, usual-ly “1⁄2 slip” or “3⁄4 slip.” Fruit harvest-ed at this stage are not as soft, but donot have as high a sugar content asthose at full maturity.

Fruit are generally ready to be har-vested 30 to 35 days following polli-nation. Frequent or daily harvests arenecessary to ensure that melons areof good quality, especially if temper-atures are high at time of harvest.Assuming good cultural practices,one can expect to harvest 2,000 to5,000 melons per acre when grownon bare ground or from 6,000 to12,000 melons when using plasticmulch.

Muskmelons need precoolingsoon after harvest to reduce fieldheat in melons. Field heat is heat ac-cumulated by the fruit growing in afield. On days with high air tempera-tures, internal temperatures withinthe fruits will often be equal to theair temperature. If field heat is notremoved, melons will degrade pre-maturely, resulting in poor qualitymelons with a greatly reduced shelflife. Precooling can be done withcold water, cold air, or ice.Hydrocooling is the most efficientmethod, but the choice among cool-ing methods depends primarily oneconomic factors and the type ofshipping container used. Buyers gen-erally specify packaging and ship-ping requirements. Room coolingand forced-air cooling are also suit-able for melons, but require moretime than methods above.

Room cooling is necessary afterprecooling in order to maintain fruitquality. Muskmelons harvested atpartial slip can be held for up to 15days at 36° to 41°F at 95 percent rel-ative humidity. Muskmelons harvest-ed at full slip may be held for 5 to 14days at 32° to 36°F at 95 percent rel-ative humidity.

The major quality factor in mel-ons, soluble solids, is the sugar con-tent of the fruit. A full-slip melon canhave as high as 15 percent solublesolids. Melons harvested at partialslip can have soluble solids rangingfrom 8 to 12 percent soluble solids.Soluble solids can be measuredquickly in the field with a hand-heldrefractometer. To maintain the sugarcontent as high as possible, keep thefoliage healthy by controlling foliardiseases, nematodes, insect pests,and weeds. Also be sure to maintaina good fertilizer and irrigation pro-gram.

ANR-974

Joseph M. Kemble, Extension Horticulturist, Assistant Professor, HorticultureFor more information, call your county Extension office. Look in your telephone directory under your county’s name tofind the number.

Issued in furtherance of Cooperative Extension work in agriculture and home economics, Acts of May 8 and June 30, 1914, andother related acts, in cooperation with the U.S. Department of Agriculture. The Alabama Cooperative Extension System(Alabama A&M University and Auburn University) offers educational programs, materials, and equal opportunity employmentto all people without regard to race, color, national origin, religion, sex, age, veteran status, or disability.

UPS, 6.5M49, New Feb 1996, ANR-974


guide to the commercial production of muskmelon (cantaloupe

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