alabama a&m and auburn universities guide to … · pumpkin and winter squash were cultivated...

ANR-1041

A L A B A M A A & M A N D A U B U R N U N I V E R S I T I E S

Guide to Commercial Pumpkin and Winter Squash Production

Historical Perspective

Pumpkins and winter squash are members of the Cucurbitaceae family (commonly re-

ferred to as the Cucumber or Gourd family).This family also contains summer squash, wa-termelons, muskmelons (cantaloupes), and or-namental gourds. Collectively, these crops arereferred to as “cucurbits.” All pumpkin andwinter squash are in the genus Cucurbita:

• C. pepo—common field pumpkins, suchas ‘Howden’ and other Jack-o-Lanterns; winterand ornamental gourds.

• C. moschata—winter squash and sometypes of pumpkins, such as ‘Dickinson.’

• C. maxima—many of the large-fruitedwinter squash and pumpkins, such as ‘BlueHubbard’ and ‘Big Max,’ respectively.

• C. mixta—Green-striped Cushaw. Pumpkins and winter squash are monecious,

producing separate male (Figure 1) and female

(Figure 2) flowers on the same plant. As a result,they require insects for cross-pollination.

Pumpkin and winter squash were cultivatedin the United States by the native Americanslong before any Europeans set foot here. Thenative Americans grew pumpkins and wintersquashes for their food and feed value. The termpumpkin is derived from the French word pam-pion meaning “sun-baked squash.” The Englishlater modified pampion to pompkin that was fi-nally changed to pumpkin by Americancolonists. Nutritionally, pumpkin and wintersquash are good sources of fiber and vitamin A.

Growing pumpkins and winter squash issuited to small and part-time farming opera-tions. Due to the great diversity in size, shape,and color, care must be taken to select varietiesthat are suited for the intended market. Thebest strategy is to establish a market beforeplanting the first seed.

Planting RecommendationsPlanting Dates

Pumpkin and winter squash are warm-sea-son crops that are relatively easy to grow butthat require a long season to produce a mar-ketable crop. Most varieties require 85 to 120days from sowing to reach market maturity.Pumpkin and winter squash should be directseeded after all danger of frost is past. Soiltemperatures should be between 70° and 90°Ffor optimal seed germination.

Pumpkins are grown primarily forHalloween. Most pumpkins are planted inJune, depending on their relative maturity.Pumpkins planted too early, particularly in thesouthern half of Alabama, can rot or requireharvesting and long-term storage before mar-keting. If you do produce a crop that maturestoo early, you can keep them in storage up to3 months, provided the pumpkins are curedand then stored properly. To avoid problems,

Figure 1. Male pumpkin flower.

Figure 2. Female pumpkin flower. Note swelling immediate-ly below flower. Following pollination and fertilization, thiswill develop into the fruit.

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2 Alabama Cooperative Extension System

try several planting dates and varieties to deter-mine the best combination in your area.

Soil And FertilityWith proper care, pumpkins and winter

squash can be grown on most soils inAlabama. Avoid low, poorly drained soils. Plantin well-drained, sandy loams with high levelsof organic matter and a pH of 6.0 to 6.5. If irri-gation is available, then use raised beds. Toavoid potential soil-borne diseases and nema-tode problems, plant pumpkins and wintersquash in soils that have not grown a crop ofwatermelons, muskmelons (cantaloupes), sum-mer squash, or other member of the Cucumberfamily in the past 2 to 3 years.

Timely and appropriate applications of fer-tilizer can make a significant difference in thequality and quantity of fruit produced. In thewinter or early spring, collect soil samples fromeach area you intend to crop and have a soilanalysis performed on each sample. Soil testingeliminates much of the guesswork involved ina fertilizer program. Contact your countyExtension agent for information on how to col-lect and submit samples. Be sure to apply limeseveral months before planting.

If you do not have the soil tested, applyenough fertilizer to supply 50 pounds per acreof nitrogen (1000 pounds per acre 5-10-10, or10 pints of 5-10-10 per 100 feet of row). At 3and 6 weeks after sowing, sidedress 6 to 8inches to the side of the plants with 20 to 30pounds per acre of nitrogen and 60 to 100pounds per acre of potassium (1 pint of 13-0-44 per 100 feet of row). Optimal potassiumlevels will insure good dry-matter production.

Seeding Rate And SpacingPrepare the land to insure establishment of

a uniform stand. Turn the soil several monthsbefore planting so that crop residues can fullydecompose. Early land preparation also allowstime for weed seeds to germinate, allowing forearly cultivation to destroy young weeds.

Plant seeds to a depth of 3⁄4 to 11⁄2 inches.To achieve the maximum stand, plant two tothree seeds per hill and thin to a single plant,leaving only the healthiest seedling. For largecommercial plantings, sow four seeds per footand thin to desired spacing. Direct seeding willrequire 2 to 3 pounds of seed per acre for

large vine types or 3 to 4 pounds per acre forbush and smaller vine types. Use Table 1 todetermine the optimal spacing for the pumpkinor winter squash you intend to produce.

Table 1. Suggested Row Spacings Based On Vine AndFruit Types.

Between Row Within Row Spacing (ft) Spacing (ft)

Bush or short vine types 3-5 2-3

Small fruited with large vine 6-8 3-5

Large fruited with large vine 6-8 3-5

Varieties Contact your county Extension agent for a

copy of the latest edition of the “Fall VegetableVariety Trials” from the Alabama AgriculturalExperiment Station at Auburn University. In thereport, you will find information on the perfor-mance of selected pumpkins and wintersquashes evaluated in several locationsthroughout Alabama. Although a large numberof commercial varieties are available, youshould grow only those adapted to Alabama.Try growing a small trial plot of several vari-eties each year to determine which varietiesare best suited to your growing conditions.

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Guide To Commercial Pumpkin And Winter Squash Production 3

Successful Pollination Of Pumpkins And Winter Squash

The following information is adapted fromCucurbit Production and Pest Management(Circular E-853) by the Oklahoma CooperativeExtension Service, Oklahoma State University.

Cucurbit crops are highly dependent on ac-tive pollination by bees. Not only does ade-quate pollination increase yield, but good pol-lination may improve the earliness and qualityof the crop. Because pollen is borne on maleflowers (Figure 1), bees are essential to transferpollen to female flowers (Figure 2). Cucurbitpollen is not effectively moved by wind.

Several factors play a significant role inmanaging bees for effective pollination. Amongthese, weather is one of the most important.Bees are less likely to forage for nectar andpollen during poor weather. If poor pollinatingconditions exist during the flowering period,additional beehives may have to be supplied.

A second factor in managing bees for polli-nation is the presence of “competing blooms”during the flowering period. Most cucurbit flow-ers are poor sources of nectar and pollen. Theymay be less attractive to bees than adjacent flow-ering weeds or other crops. In such cases, cropsthat may attract bees away from the pumpkinsor winter squash during the blooming periodshould not be planted nearby (at least a 1⁄2 milebuffer is desirable). Similarly, weeds adjacent tothe crop that may serve as competing bloomsbefore the pumpkins or winter squashes beginto bloom should be destroyed. Although suchwild flowers can be detrimental if they areblooming in mass at the same time as the targetcrop, their availability during other times helpsinsure that bee colonies are well nourished andremain healthy.

The use of domesticated honeybees is themost effective means to pollinate cucurbitcrops. However, wild bees or feral honeybeescan be extremely important as pollinators. Wildbees include several species of native, ground-nesting bees that prefer pollen and nectar fromspecific cucurbits. The abundance of wild beesvaries greatly by location and from year toyear, making them less dependable than do-mesticated bees. For this reason, it is strongly

recommended that managed honeybeecolonies supplement any wild bee activity.

Fruit size and seed set of cucurbits arestrongly related to bee activity. Cucurbit flowersare open for only 1 day, and squash flowers areusually open only in the morning. Because ofthe large size of the flowers and pollen, thesmall honey bees do not pollinate squash as effi-ciently as larger native bees. The pollination re-quirement of pumpkin and squash is similar tothat of muskmelon (cantaloupe); one bee perten “female” flowers is considered the minimumlevel of activity to maximize production. A mini-mum of one honey bee hive per acre is normal-ly necessary to achieve this level of activity.Yield increases have been achieved with up tothree hives per acre.

IrrigationAfter marketing, irrigation is the second

most important element of a successful veg-etable production operation. Keep in mind thatirrigation is essential to the production of qual-ity produce. Most vegetables are 90 percentwater, so any loss in water weight is equal to a loss in salable weight. Whether you are usingoverhead or drip irrigation, provide sufficientwater to the crop to insure the production ofhigh yields of quality fruit.

In pumpkin and winter squash production,the most critical period for irrigation is whilefruits are sizing. In pumpkin, any stress relatedto lack of water during fruit sizing can lead tothe development of blossom-end rot. In pump-kin and winter squash, fruit size and yield areseverely reduced by moisture stress.

Mulching And Drip IrrigationUsing polyethylene (plastic) mulch offers

growers several advantages. Plastic mulch in-creases the soil temperature, accelerating plantgrowth and development. It also conserves soilmoisture and reduces several common problems,such as soil compaction and crusting, ground rotof fruit, fertilizer leaching, drowning of crops,evaporation, and competition from weeds.

Although using mulch will increase produc-tion costs, those costs are offset by increasedprofits from earlier and larger yields of high-quality produce. Drip irrigation systems mustbe used with plastic mulch. In addition, grow-

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ers can plant multiple crops (double-cropping)into the plastic mulch if the mulch is not exces-sively damaged (torn or ripped). Double-crop-ping will spread production costs over twocrops, decreasing the risk associated with thehigher initial set-up costs. Pumpkin and wintersquash can be planted on mulch that was usedto produce a spring crop, such as cabbage, col-lards, broccoli, or strawberries. The drip tapeshould be offset 3 to 4 inches from the centerof the bed and buried 2 to 3 inches deep.Contact your county Extension agent for moreinformation regarding the use of plastic mulchand drip irrigation.

Weed ControlChemical weed control options in pumpkin

and winter squash are very limited. Most herbi-cides registered for use provide annual grassand small-seeded broadleaf weed control (pig-weed), but do not control large-seededbroadleaf weeds, such as sicklepod, annualmorningglory, or common cocklebur. Refer toCircular ANR-500A, Alabama Pest ManagementHandbook—Volume 1, for a listing of herbi-cides currently registered for pumpkin andwinter squash. Be sure to apply pre-emergenceherbicides immediately after seeding. Some va-rieties of winter squash are more sensitive tocertain herbicides and may be injured if youapply the herbicide as seeds germinate.

For better weed control, select locations withlow weed populations or no perennial weedproblems, such as nutsedge. Use mechanical cul-tivation between rows, and employ productionpractices which encourage rapid development of pumpkin and winter squash. When using me-chanical cultivation, cultivate the soil only 1 to 2inches deep because pumpkin and wintersquash are shallow rooted and sensitive to rootpruning. Some hand weeding may be needed.Consider using polyethylene mulch as part ofyour weed control strategy.

Insect ManagementMany insects can have an impact on cucur-

bit production in Alabama. Some pest insectscause problems, but the benefits from other in-sects, such as bees, are essential for successfulproduction. When developing a pest manage-ment program, take care to preserve beneficialinsects. Refer to Circular ANR-500A, AlabamaPest Management Handbook—Volume 1, for alisting of insecticides currently labeled for useon pumpkin and winter squash.

Insect Scouting MethodsDepending on your location in the state

and the planting date, insect problems in win-ter squash and pumpkins can vary from nonex-istent to severe. It is important to be able torecognize pests and to understand their poten-tial for damage when selecting appropriatecontrol methods. Each pest does not respondthe same way to a given control method.

Monitor fields at least once a week bywalking a V or W pattern through the field and selecting plants from 10 random locationsalong the V or W pattern. When plants aresmall (up to 10 leaves), examine five adjacentplants per location for insect and disease pests.As plants get larger, sample two leaves perplant on five adjacent plants per location (totalof 100 leaves). Use a hand lens to detect smallpests, such as aphids and spider mites.

Soil InsectsFeeding damage by soil insects usually oc-

curs when plants are young, and can result inpoor stands. Soil insects can also destroy seedsas they begin to germinate. Feeding on youngroots by soil insects, such as whitefringed bee-tle grubs, white grubs (larvae of May and Junebeetles), wireworms, and the larvae of cucum-ber beetles, reduces nutrient and water uptake,causing plants to wilt and die. Cutworms alsofeed on roots, or they may cut young stemsabove the soil line. White grubs and wire-worms are most abundant in fields that werepreviously in pasture, planted to a grass crop,or left fallow with large weed populations.

Base the decision to treat for soil insects onthe cropping history and the potential of thefield to have pest problems. Apply a pre-plantsoil insecticide if you are planting squash orpumpkin into an area that was previously in pas-

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ture or was infested with weeds. If you suspectcutworm damage, check the soil around theplants for dark caterpillars that roll into a Cshape when disturbed. Control cutworms afterplanting by applying a recommended insecticidespray directed towards the base of the plants.

Cucumber BeetlesSpotted and striped cucumber beetles at-

tack young seedlings when they emerge. Thebeetles are yellow to greenish yellow, withblack spots or stripes (Figure 3). If beetles arenumerous, feeding damage will weaken or killseedlings. Beetles can also transmit bacterialwilt, a disease that occasionally affects squash.It is thought that beetles pick up the bacteriafrom adjacent weeds and carry it into produc-tion fields. Infected plants wilt, then rapidlydie. Younger plants are most susceptible to in-fection before bloom.

The critical period for cucumber beetlecontrol is within the first 2 to 3 weeks afterplant emergence. Apply a recommended insec-ticide if beetles are detected during this period,particularly if the field has a history of bacterialwilt disease. Alternately, use row covers toprotect plants from beetles before flowering.Control weeds to reduce the amount of bacteri-al wilt inoculum that is available to the beetles.

Figure 3. Striped cucumber beetle.

Figure 4. Squash bug with nymphs.

Squash BugsAdult squash bugs emerge in the spring from

overwintering sites in field debris, along fieldborders, or in nearby woods. Adults are about 1⁄2to 3⁄4 inch long and dark to gray brown in color.The tops of their bodies are flattened, withwings not completely covering the orange andbrown edges of the abdomen. Eggs are laid in a mass, usually on the leaf underside, and turnmetallic bronze in color within a few hours.Newly hatched squash bugs (nymphs) are wing-less and pale green to white, with reddishbrown heads and legs (Figure 4). Older nymphsare gray, with black legs.

Adults and nymphs suck sap from theplant. If feeding is severe, the leaves turnbrown and die. Vines that are fed upon wiltfrom the point of attack to the end of the vine.Large populations of squash bugs cause plantsto wilt under hot, dry conditions; however theplant will recover if squash bugs are controlledin time. Feeding may also occur on fruit, caus-ing misshapen fruit to develop.

There are two critical periods for manage-ment of squash bugs: the seedling stage andthe early flowering stage. Monitor newly plant-ed fields for squash bug adults and/or wiltingof plants. If you observe wilting, check the un-derside of leaves for squash bug adults or evi-dence of their feeding. Apply a pyrethroid in-secticide to control adults.

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Once plants are established, monitor themweekly for adults and eggs. Apply a foliar in-secticide if the average number of egg massesper plant before or after flowering exceeds oneper plant. Time sprays to kill small nymphs,which are more susceptible to insecticides.Good spray coverage (that is, at least 30 GPAby ground application) is important for effec-tive control. Remove and destroy crop debrisafter harvest to reduce overwintering squashbug populations.

Squash Vine BorerSquash vine borers are usually more of a

problem in home gardens than in commercialfields. Vine borer infestation is usually not no-ticed until after the damage is done. The adultvine borer is a “clear-wing” moth that resem-bles a wasp. The body is reddish white, withblack bands on the abdomen. Females lay eggsat the base of the plant. The emerging larvaeenter the stems just above the soil line. Larvaefeed inside the stems, causing wilting and theeventual death of the occupied parts of theplant (Figure 5). Infested stems can be identi-fied by entry holes with piles of “frass” or ex-crement. Squash vine borers prefer cucurbitswith large-diameter stems, such as ‘Hubbard’squash.

In areas with a history of vine borer prob-lems, monitor plants regularly for the presenceof borer frass and entry holes. If you find frass,split stems to check for presence of young bor-ers. If young larvae are present, reduce furtherinfestation by hatching larvae by making twoinsecticide applications spaced 5 to 7 daysapart. Plantings in late summer or fall usuallyescape vine borer infestations.

AphidsAphids are small, soft-bodied insects, usual-

ly green or sometimes red, with piercing-suck-ing mouth parts. Developing aphid coloniesare usually found on new growth or on the underside of leaves. Infested leaves appear dis-torted or cupped. If numerous, aphids maycause direct damage to plants by their feedingor their production of “honeydew” (syrupy ex-crement) and accompanying “sooty-mold” thatmay cover fruit. The primary damage causedby aphids, however, results from the manyplant viruses they can transmit.

Aphids have many natural parasite andpredator enemies that help to keep popula-tions in check. Application of insecticides thateliminate natural enemies, therefore, may in-crease the numbers of aphids. Insecticides arenot effective in preventing aphid transmissionof many viruses. Insecticides are only recom-mended to control aphids if they are present insufficient numbers to cause direct damage toplants. An insecticide application is warrantedif aphids are present on 10 to 20 percent ormore of leaves, and their feeding is causingobvious stress to the plants. Late summer orfall plantings of squash and pumpkin are likelyto experience more severe virus problems thanare earlier plantings.

Spider MitesMites are not insects but are more closely re-

lated to spiders. They are tiny, about 1⁄25 to 1⁄50

inch long, and are either red or whitish yellowwith black spots on either side. They feed bysucking sap from plants and are usually locatedon the underside of leaves. They are easily seenwith a hand lens, along with their round, yelloweggs and webbing that they produce.

The first sign of feeding is the appearance oflight-colored specks on the upper leaf surface.Leaves turn yellow, then bronze, and eventually

Figure 5. Squash vine borer and characteristic dam-age.

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ops on the underside of leaf spots on thelower leaf surface. Leaf spots merge and turntan to brown. Infected leaves eventually die,but remain erect while the edge of the leafblade curls inward. Spread is rapid from thecrown leaves outward towards new growth.When severe, downy mildew can cause defoli-ation, stunting, and reduced yields.

Downy mildew is spread by wind currents,in water droplets in heavy rains or during irri-gation, and mechanically by field workers oron equipment. Moist conditions, high humidity,and moderately warm temperatures favor dis-ease development.

To control downy mildew, avoid fields withpoor drainage, and use drip irrigation. Start afungicide spray program when the disease ap-pears. Bury or destroy plant debris after har-vest.

Powdery MildewAll cucurbits are susceptible to powdery

mildew which is caused by a number of fungalgenera. Symptoms first appear as pale yellowspots on stems, petioles, and leaves. Thesespots enlarge, and a white talcum-powder-likefungal growth appears on both the upper andlower leaf surfaces (Figure 7). Symptoms first

Figure 6. A melon leaf with symptoms of downymildew.

Figure 7. Symptoms of powdery mildew on theupper and lower leaf surface.

turn brown and dry up. Once mite populationsbecome large with a lot of webbing and plantdamage, they are nearly impossible to control.Hot, dry conditions favor mite development.Mites “float” onto plants using their silk as aparachute lifted by wind currents.

Mite infestations usually begin on field bor-ders. Check field borders regularly, particularlyduring hot, dry weather. Plants that become cov-ered with dust raised by vehicular traffic aremore prone to severe mite infestations. If youfind mites along a field border, examine the inte-rior of the field to see how far the infestation hasspread. If only the border is effected and condi-tions favor mite development, spot-treat the bor-der and about 100 feet beyond the infestationwith a recommended miticide.

Some insecticides, particularly carbamateand pyrethroid insecticides, can worsen miteproblems by destroying natural enemies.Insecticidal soap is effective for control of soft-bodied pests like aphids and mites without de-stroying natural enemies.

Control Of Pumpkin AndWinter Squash Diseases AndNematodesDowny Mildew

All cucurbits are susceptible to downymildew, caused by the fungusPseudoperonospora cubensis. Symptoms firstappear on older leaves near the center of theplant. Infected leaves first appear mottled; thenyellow spots develop on the upper leaf surface(Figure 6). These spots are angular and limitedby major veins. Under moist conditions a whiteto gray to purple, fuzzy fungal growth devel-ARCHIVE


The fungus survives from season to seasonon crop debris or on other cucurbit crops orweeds. Seed of rotted fruit can be contaminatedwith the fungus. Disease development is favoredby warm temperatures and wet weather. Plantsdamaged by other pests or weakened by stressare more susceptible to black rot. The fungusenters the fruit through wounds in the rind.

Control black rot by rotating fields out ofcucurbit crops for 2 or more years. Avoid fieldswith poor drainage. Do not save seed from acrop in which black rot was a problem. To reduce black rot incidence, begin a fungicidespray program that controls gummy stemblight. During the season and at harvest, avoidwounding rind tissue on winter squash andpumpkins. Cure harvested fruit properly toallow wounded areas to heal themselves in afew weeks.

AnthracnoseAnthracnose, caused by the fungus

Colletotrichum lagenarium, is a destructive dis-ease of cucurbits during warm, wet growingseasons. Gourds are considered susceptible toanthracnose, while squash and pumpkin arehighly resistant.

All aboveground plant parts are susceptibleto infection, and plants can become infected atany stage in their development. Older leavesfirst show small, water-soaked or yellowishareas that enlarge rapidly and turn tan to red-dish brown. Spots are often circular to angularat first, eventually merging and blighting largesections of the leaf. These areas become dryand tear away, typically giving the foliage aragged appearance. Often the leaves at thecenter of a plant are attacked first, leaving thestem and runners bare. Tan to black, elongat-ed, slightly sunken streaks form on petiolesand stems. These streaks can girdle the vine,killing the tissue beyond the lesion. Fruit, if in-fected early, may turn black, shrivel, and die.Round, water-soaked spots, 1⁄4 to 21⁄2 inches indiameter, develop on the older fruit. Spots turna dark green to brown with age and may be-come sunken. Under wet conditions, pinkishcolored spore masses begin oozing out of thesunken spots.

appear on older leaves or shaded lower leaveson mature plants. Infected leaves graduallyturn yellow and become brown and papery asplants die prematurely. Fruit infections are rare.

The fungus overwinters on weeds and isspread long distances by wind currents.Disease development is favored by dense plantgrowth, moderate temperatures, low light in-tensity, and dews.

To control powdery mildew, plant resistantvarieties when available. Where resistance isnot an option, use fungicides. Weed controland good sanitation practices will help controlpowdery mildew. After harvest, destroy or buryall plant debris.

Black RotBlack rot, caused by the fungus Didymella

bryoniae, is a major problem on winter squashand pumpkin, and to a lesser extent ongourds. The disease is known as gummy stemblight on watermelon and cantaloupe. Blackrot can appear in the field on fruit before har-vest or during storage. Symptoms begin as ir-regular, faded green or yellow, circular spotson the fruit. Spots later turn gray to brown andfinally black (Figures 8a and 8b). The funguscan penetrate the rind and cause a dry rot.Secondary fungal or bacterial rot organisms canenter through these wounds and cause a soft,watery rot of the entire fruit.

Figures 8a and 8b. Black rot on butternut squash inthe field (above) and in storage (below).ARCHIVE

ing of the inter-nodes. In severecases, older leavesmay die. Typicalmosaic symptomsdevelop only onactively growingleaves. When aplant becomes in-fected at midsea-son, previousgrowth usually re-mains normal andproduces healthy fruit. Few fruits set on plantsinfected early in the growing season. Fruits thatdo set are often of poor quality and may bemottled green (Figures 9a and 9b) or havewarts (Figure 10).

The fungus overwinters in plant debris, inseed, or on cucurbit weeds. Warm, wet condi-tions favor rapid development and spread ofthe disease. Anthracnose can appear anytimeduring the season, but most damage occurslate in the season after fruit set.

To control anthracnose, plant certified dis-ease-free seed. Plant cucurbits in an area nomore than once every 3 years. Plant in well-drained soil free from surface run-off water.Follow a weekly spray program with a recom-mended fungicide beginning at the first trueleaf stage. Bury or destroy all plant debris afterharvest.

Mosaic VirusesMany viruses attack cucurbits in Alabama.

Some of the most common viruses found inAlabama include cucumber mosaic virus(CMV), watermelon mosaic virus (WMV), zuc-chini yellow mosaic virus (ZYMV), and papayaringspot virus (PRSV). Symptoms produced bythese viruses are similar, making field identifi-cation impossible. Special laboratory testing isrequired for positive identification.

Cucurbits are susceptible at any stage ofgrowth. When plants become infected in thesix- to eight-leaf stage, symptoms first appearon the youngest, still expanding leaves. A mo-saic pattern often develops (healthy dark greenleaf tissue intermingled with light green andyellow tissues) (Figures 9a and 9b). Leaves areoften distorted, crinkled, curled, and stunted.Vines may appear bunchy due to the shorten-


Figures 9a and 9b. Mosaic virus symptoms on pump-kin (above) and winter squash (below) foliage andfruit.

Figure 10. Mosaic virus symp-toms on pumpkin (fruit).ARCHIVE


Mosaic viruses typically overwinter in surroundings weeds, which are a reservoir for the viruses. In spring, theseviruses are spread from weeds into cultivatedcrops by insects, usually aphids.

Control mosaic viruses in cucurbits by eradicating biennial and perennial weedsand wild reservoir hosts in and around gardensand fields. Apply insecticides to prevent thebuildup of large aphid populations, as well asother insects, and to reduce virus incidenceand spread. When possible, plant certifiedvirus-free seed. Isolate later plantings far fromearlier settings, especially if virus incidencewas high. Removing infected plants whensymptoms first appear may reduce or delayspread of the disease. Use reflective mulchesand row covers to reduce damage from insect-transmitted viral diseases.

Root-Knot NematodeAll cucurbits are susceptible to root-knot ne-

matode, caused by Meloidogyne spp. Affectedplants may be stunted and show signs of a nutri-ent deficiency (yellowing foliage). Symptoms aremore severe on light, sandy soils. Heavily infect-ed plants may wilt during the warmest part ofthe day. Roots on infected plants will have galls,knots, or swellings that vary in size from thehead of a pin to 1⁄2 inch in diameter on largerroots (Figure 11). Galls on severely infectedroots may fuse causing the root system to appearmalformed. The disruption in normal rootgrowth and activity affects the plant’s ability totake up water and essential nutrients.

Root-knot nematodes can survive in an areafor many years without a host. The nematodealso has a wide host range that includes mostcultivated crops.

Controlling root-knot nematodes is difficultbecause no resistant varieties are available.Rotating cucurbits with a grass crop or a nema-tode-suppressive crop, such as sesame or vel-vetbean, will reduce the nematode populationbut will not eliminate root-knot from the soil.Clean fallowing is another option. Soil fumiga-tion may be economical.

Harvesting And CuringPumpkin and winter squash are still alive

even after they have matured and are removedfrom the vine. The objective of curing and stor-age is to prolong the post-harvest life of the fruit.

Mature pumpkins and winter squash storebetter than immature fruit. When mature, win-ter squashes, such as ‘Butternut,’ ‘Acorn,’ and‘Hubbard’ types, have hard skins that resistpuncture with your thumbnail. Skins of wintersquash appear dull and dry compared to thefresh, bright sheen of the skin of immaturefruit. Leave a long stem (handle) on pumpkins.On winter squashes, such as the ‘Hubbard’types, remove the stems completely.

Keep in mind that dead vines do not indi-cate maturity in pumpkin and winter squash.When vines die prematurely from disease ordrought, for example, the fruits are likely im-mature and will not store successfully.

Curing involves elevating storage tempera-tures to 80° to 85°F with 75 to 80 percent rela-tive humidity for approximately 10 days.Curing heals wounds, helps ripen immaturefruit, enhances color, and insures a longerpost-harvest life. After curing, reduce tempera-ture and relative humidity as indicated in Table2. Curing is beneficial in pumpkins and somewinter squash, but ‘Butternut,’ ‘Hubbard,’ and‘Quality’ squashes have not shown any addedbenefits from curing. Curing is detrimental inAcorn types, such as ‘Table Queen.’

Figure 11. Root-knot galls on pumpkin.

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Table 2. Storage Recommendations For Pumpkins And Winter Squash.

Type Approximate Temperature Relative RemarksLength of Conditions HumidityStorage

Pumpkins 2-3 months 50-55°F 50-75% Should be well-matured

Winter Squash

Hubbard 5-6 months 50-55°F 70-75% Holds well in storage

Acorn 5-8 weeks 50°F 50-75% Develops poor color at higher temperatures

Butternut. Turban,Buttercup 2-3 months 50°F 50-75%

StorageAll pumpkins and winter squash should be

well matured and free from injury and decaywhen stored. They should be kept dry andprovided with good air circulation. Control hu-midity because high humidities will promotedecay and lower humidities will cause exces-sive weight loss. When winter squashes aretaken out of storage, they should be marketedimmediately (see Table 2).

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ANR-1041

J. M. Kemble, Extension Horticulturist, Associate Professor, Horticulture; E. J. Sikora, ExtensionPlant Pathologist, Associate Professor, Entomology and Plant Pathology; G. W. Zehnder,Extension Entomologist, Associate Professor, Entomology and Plant Pathology; and E. Bauske,former Extension Associate, Horticulture; all at Auburn University

Use pesticides only according to the directions on the label. Follow all directions, precautions, and restrictions that are list-ed. Do not use pesticides on plants that are not listed on the label.

The pesticide rates in this publication are recommended only if they are registered with the Environmental ProtectionAgency and the Alabama Department of Agriculture and Industries. If a registration is changed or cancelled, the rate listedhere is no longer recommended. Before you apply any pesticide, check with your county Extension agent for the latest in-formation.

Trade names are used only to give specific information. The Alabama Cooperative Extension System does not endorse orguarantee any product and does not recommend one product instead of another that might be similar.

For 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,and other 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 employ-ment to all people without regard to race, color, national origin, religion, sex, age, veteran status, or disability.

UPS, 6M48, Reprinted Feb 2000, ANR-1041

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