Squash (cucurbita moschata) production Guide agriculture, forestry & fisheries Department: Agriculture, Forestry and Fisheries REPUBLIC OF SOUTH AFRICA B Squash (cucurbita moschata) production Directorate: Plant Production DEPARTMENT OF AGRICULTURE, FORESTRY AND FISHERIES i 2011 Printed and published by Department of Agriculture, Forestry and Fisheries Design and layout by Communication Services Private Bag X144, Pretoria 0001 DISCLAIMER This document has been compiled by the Department of Agriculture, Forestry and Fisheries and every effort has been made to ensure the accuracy and thoroughness of the information contained herein. The department cannot, however, be held responsible for any errors, omissions or inaccuracies in such information and data, whether inadvertent or otherwise. The Department of Agriculture, Forestry and Fisheries, therefore, accepts no liability that can be incurred resulting from the use of this information. CONTENTS Part 1: General aspects 1. Classifi cation 1 2. Origin and distribution 1 3. Major production areas in South Africa 1 4. Description of the plant 2 5. Cultivars 3 6. Climatic requirements 4 7. Soil requirements 5 Part 2: Cultivation practices 1. Propagation 6 2. Soil preparation 6 3. Planting 6 4. Fertilisation 7 5. Irrigation 8 6. Weed control 8 7. Pest control 9 8. Disease control 11 9. Other cultivations practices 15 10. Harvesting 16 Part 3: Post-harvest handling 1. Sorting and grading 18 2. Packaging 18 3. Storage 18 4. Market preparation 19 Part 4: Production schedule 19 Part 5: Utilisation and nutritional value 21 Part 6: References 22 PART 1: General aspects The taxonomy of the Cucurbit family varies with three different cucurbit species, namely Cucurbita maxima, commonly known as pumpkins, Cucurbita pepo, known as squashes and Cucurbita moschata which comprise butternut squashes. Squash or “kalabasa” is a viny, creeping and trailing crop producing fruit and consid- ered to be one of the most delicious vegetables. It is the most commonly and regu- larly grown among the cucurbits because it is a rich source of vitamin A, phosphorus and calcium. The young and tender shoots make good vegetable salads. 1. CLASSIFICATION Scientifi c name: Cucurbita moschata Common names: English common names include winter squash, zucchini, but- ternut, pumpkin, gourd, cushaw and marrow. South African common names: leputshe (Setswana), botterskorsie (Afrikaans), Family name: Cucurbitaceae 2. ORIGIN AND DISTRIBUTION Cucurbita were originally domesticated in Mexico, South America, and the eastern U.S. C. maxima and especially C. fi cifolia are more cold tolerant than the other spe- cies and are thought to have been domesticated in the tropical highlands of North and South America. 3. MAJOR PRODUCTION AREAS IN SOUTH AFRICA Butternut (Cucurbit moschata) is an important summer crop grown by smallholder irrigation farmers in South Africa and is a type of winter squash. Butternut squashes are increasing in popularity because production and keeping quality are good and sunburn is not a major problem. The harvested fruit is hardy and can be left on the land for a month or two. It has a sweet, nutty taste similar to that of a pumpkin. It has yellow skin and orange fl eshy pulp. When ripe, it turns increasingly deep orange, and becomes sweeter and richer. It grows on a vine. 3.1 South Africa Squash is mainly grown in the Mpumalanga Highveld, Mpumalanga Lowveld, and Gauteng (in the Vaal region). 1 4. DESCRIPTION OF THE PLANT 4.1 Botany Squash is a tender tendril-bearing and viny-like plant belonging to the family Cucurbitaceae of gourd family. The fruit is large and variable in shape, size, colour and markings with a peduncle that is large, soft and corky on the surface at maturity. 4.1.1 Roots Rooting commonly occurs at the stem nodes, which may improve plant vigour. Adventitious roots are also commonly formed at its nodes. 4.1.2 Stem It has a very course, prostrate or climbing annual, herbaceous vine, reaching a length of 4 m or more and fl owering throughout the year. Some varieties produce tendrils that help secure vines, limit wind damage and improve vine growth across weedy and uneven ground. 4.1.3 Leaves The leaves are broadly rounded and heart shaped. The leaf occurring at the node where a fruit is developing is called the “feeder” leaf because photosynthates from the leaf are preferentially translocated to the adjacent fruit. If present, tendrils indicate ripeness in mature squashes when they begin to brown. 4.1.4 Flowers Flowers are erect, lemon yellow to deep orange in colour, about 12 cm long, the male fl owers with longer peduncles than the female ones—15 to 30 cm in diameter. Flowers are generally large with separate male and female fl owers borne on the same plant (monoecious). Male fl owers form fi rst. 4.1.5 Seeds Seeds are large (up to 3 cm long). Numerous seeds are embedded in the tissue of the placenta which lies at the centre of the fruit. 4.1.6 Fruit shape Fruit varies in shape (fl attened, elongated, smooth, and ribbed) and size (0,25 to 6 kg or more). After pollination, fruit develops from the preformed ovary at the base of female fl owers. The shape of the ovary prior to pollination is indicative of the mature fruit shape. 2 5. CULTIVARS There are several types of winter squash based primarily on fruit shape and texture. Acorn—Acorn squashes are deeply ridged and tapered at one end. They have a dark green rind and a fi rm yellow fl esh. They weigh between 0,45 kg and 1,4 kg. Both bush and vining types are available. Butternut and Waltham butternut—these have cylindrical fruit that often bulges around the seed cavity. They have light tan rinds with orange fl esh and are vining in growth habit. Buttercup and Turk’s Turban—these turban-shaped squashes have rinds that can be multicoloured with green, orange, or grey stripes. The fl esh is medium orange. Spaghetti Squash—this squash is also called vegetable spaghetti. The cylindrical (20 to 23 cm long) fruit has a yellow fl esh that is stringy. Hubbard—these are round in general shape but taper to a point at the blossom end. The rind is rough bluish-grey to green with occasional grey stripes. The fl esh is orange-yellow in colour. Table 5.1 Cucurbita genus Cucurbita pepo* Cucurbita Cucurbita Cucurbita Cucurbita (variety melopepo) pepo (variety maxima moschata argyosperma* pepo) Zucchini (summer Acorn squash Buttercup Butternut Cushaw squash variety) (winter variety) squash squash (summer variety) (winter (winter va- variety) riety) Yellow crooknook Delicata squash Hubbard Winter Cushaw squash squash (summer (winter variety) squash crookneck variety) (winter squash variety) Scallop squash Spaghetti Banana (summer variety) squash (winter squash variety) (winter variety) Boston marrow squash (winter variety) 3 Cucurbita pepo* Cucurbita Cucurbita Cucurbita Cucurbita (variety melopepo) pepo (variety maxima moschata argyosperma* pepo) Turk’s turban squash (winter variety) 6. CLIMATIC REQUIREMENTS All cucurbits are warm-season crops. They grow best during hot weather and cannot tolerate frost. 6.1 Temperature Squash can be grown in both the wet and dry season. It has been reported that en- vironment can have a marked infl uence on development and quality of the fruit. The optimum monthly average temperature for good growth is from about 180C to 270C. Likewise, warm temperature and low relative humidity favour good fruit-setting devel- opment and quality of the fruit. Seeds will germinate at 15°C, but germinate best at 29°C to 32°C. Squashes grow best at temperatures of 23°C to 29°C (day) and 15°C to 21°C (night). Growth virtu- ally stops at temperatures below 10°C and the plants may be severely damaged and maturity could be delayed by temperatures below 5°C for several days. Plants are usually killed by one hour or more of frost (temperature below 0°C). Therefore, plant cucurbits in the fi eld when soil temperatures are high enough for good germination and all chances of frost have passed. For early summer squash production, plastic mulch and/or row covers will raise soil temperatures and provide some frost protection. Low temperatures also have an adverse effect on fl owering and fruit set. Cucurbits are monoecious plants—that is, each plant produces both male and female fl owers. Normally, several male fl owers form before female fl owers develop. During the peri- ods of cool temperatures (below 22°C) most pumpkin and squash cultivars respond by producing primarily male fl owers. Male fl owers do not form fruit. By contrast, some cultivars of summer squash appear to form mostly female fl owers in response to cool temperatures. However, without male fl owers to provide pollen the female fl owers do not form fruit. 4 7. SOIL REQUIREMENTS 7.1 Site and soil It thrives on many types of soil but it grows well on an organic-rich medium and is of- ten found on compost or refuse heaps. A soil pH range of 5,6 to 6,5 is recommended. Squashes grow well on most well-drained soils. Sandy loams are ideal. They also grow well on clay soils, but harvesting is diffi cult when soils are wet and the fruit of- ten becomes dirty and diffi cult to clean. Avoid production on low-lying or muck fi elds where plants are subject to late spring or early autumn frosts. 5 PART 2: Cultivation practices 1. PROPAGATION Cucurbita is easily and almost exclusively propagated by seed. However, plants can be reproduced vegetatively via cuttings. Vegetative reproduction is generally not dif- fi cult, but ease of propagation is dependent on rooting conditions and plant health. Cuttings of one to three nodes from healthy, vigorous plants with a small feeder leaf will root readily in moist and well-drained media.