Sponge gourd (Luffa cylindrica, syn. Luffa aegyptica), commonly known as vegetable sponge, bath sponge, loofah or dish cloth gourd, is a member of cucurbitaceous vegetable. The young tender fruits are commonly used for culinary purpose. It is cultivated throughout India on a commercial scale in garden lands, river beds and kitchen gardens for edible tender fruits. Besides being an important vegetable it is emerging as an industrial and pharmaceutical crop.
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Climate and soil
The sponge gourd is well adapted to a fairly wide range of climatic conditions in tropical and sub-tropical regions of the country, but it performs best under hot and humid conditions with a temperature range of 25-27°C. Very high temperature (>38°C), particularly at early stage of growth, reduces fruit yield due to more number of staminate flowers, whereas, excessive vegetative growth is promoted with high temperature and high relative humidity in rainy season. The plants bear more pistillate flowers when temperature is comparatively low, days are long, and relative humidity is high. Under shade or very low light intensities, tendency to produce male flower is more.
It can be grown on a variety of soils. A well-drained sandy-loam soil with high organic content is considered best. The soil pH range between 5.5-7.5 is desirable for growth and yield of the crop. The soil temperature between 18-22°C is highly suitable for maximum germination of the seed. Like other cucurbits, sponge guard during vegetative growth requires optimum soil moisture rather than excessive moisture content, thus, the crop is mostly grown as a rain fed crop.
Large variations prevail in fruit colour, shape and size of sponge gourd, and its cultivation/consumption depends on the regional preference. Improved varieties released by various institutes/universities are discussed here.
Azad Torai Chikani 1: Fruits smooth and green. It is suitable for growing in rainy season. An early maturing variety with yield potential of 18-20 tonnes/ha.
Azad Torai 2 (KSG 14): Fruits are compact, attractive, green and rich in nutrients. It is recommended for cultivation in agro-climatic zone IV (Punjab, Uttar Pardesh, Bihar and Jharkhand). Its yield potential is 15-20 tonnes/ha.
Gujarat Sponge Gourd 1 (JSGL 55):Fruits are cylindrical, light green, fruit length 20-25 cm and seeds black at maturity. First fruit harvest can be taken 52-60 days after sowing. This variety is recommended for cultivation in agro-climatic zone – VII (Madhya Pradesh, Maharashtra and Goa). Potential yield of this variety is 12-15 tonnes/ha.
Kashi Divya (VR-1): Fruits are cylindrical, light, fruit length 20-25 cm. First fruit harvest can be taken 48-50 days after sowing. It is resistant to Anthracnose disease and tolerant to Downy mildew. Tolerant to leaf minor, fruit fly and red pumpkin beetle. This variety has been recommended for cultivation in agro-climatic zone – IV (Punjab, Uttar Pradesh, Bihar and Jharkhand). It has a yield potential of 13.0-16.0 tonnes/ha.
Kayanpur Hari Chikani: Fruits are long, smooth and dark green with pointed distal end. It is an early variety with first fruit harvest at 60-70 days after sowing. It has yield potential of 17.5-20.0 tonnes/ha.
Pant Chikani Taroi 1 (PSG 40):Fruits are cylindrical, long (about 25 cm), green with tapering ends. First harvest can be taken 50-60 days after sowing. This variety has been recommended for cultivation in agro climatic zone VII (Madhya Pradesh, Maharashtra and Goa) and zone – I (Jammu and Kashmir, Himachal Pradesh and Uttarakhand). It has yield potential of 14 17 tonnes/ha.
Pusa Chikni: Fruits are smooth, dark green, more or less cylindrical, 15-20 fruits/vine and suitable for both spring-summer and rainy seasons. Fruits are ready for harvest at 60-70 days after seed sowing. Potential yield of this variety is 10 tonnes/ha.
Phule Prajakta: Fruits are straight, slender and tapering. Male flowers appear in clusters at each node and female flower at each node. Fruits are ready for first picking at 52-59 days after sowing. It is highly tolerant to downy mildew and moderately tolerant to fruit fly and red pumpkin beetle. It is suitable for growing in both kharif and zaid season. Its yield potential is 15.8 tonnes/ha. PSG 9: Fruits smooth, long, tender and dark green. It is ready for first picking at 65 days after seed sowing. Its yield potential is 16.2 tonnes/ha.
Pusa Sneha: Fruits are attractive dark green, 20-25 cm long and straight. First picking starts at 50-55 days after sowing in spring-summer and 45-50 days in rainy season. It is suitable for both spring-summer and rainy seasons. Potential yield of this variety is 20-23 tonnes/ha.
Pusa Supriya (Sel 99): Fruits are pale green, smooth, 15-20 cm long, straight and slightly curved at the stem end, pointed distal end, non-hairy, flesh tender, suitable for spring summer and kharif season. Fruits become ready for picking in 50-55 days after sowing in spring summer and 44-48 days after sowing in kharif season. It is recommended for cultivation in agro-climatic zone – IV (Punjab, Uttar Pradesh, Bihar and Jharkhand) and zone VI (Rajasthan, Gujarat, Haryana and Delhi). Average yield of this variety is 13.0-14.0 tonnes/ha.
Rajendra Nenua 1: Fruits are smooth, greenish white and medium in size (28.33 x 4.85 cm) with good cooking quality. Early fruit setting noted at fifth internode. Fruits are ready for first picking at 62-65 days after seed sowing. It is tolerant to powdery mildew, fruit rot and to beetle. Mature seed is black. Suitable for both seasons (kharif and zaid). Its yield potential is 32.5 tonnes/ha.
Swarna Prabha (CHSG 1): Its fruits are medium in length (20-25 cm), weighing 150-200 g each, light greenish, pulp soft and contain less fibre. First fruit harvest can be taken at 70-75 days after seed sowing. It is tolerant to powdery and downy mildew and resistant to leaf miner under field conditions. It is recommended for cultivation in agro-climatic zone – IV (Punjab, Uttar Pradesh, Bihar and Jharkhand) during July-September and February-April. It has yield potential of 200-250 q/ ha.
The sponge gourd is propagated through seed. The flowers of sponge gourd open in early morning hours (4.0-8.0 am) and are suitable for selfing and crossing almost through the day. The seeds are black or white, flat, smooth and without margin. About 3-4 kg seed is enough for 1 ha whereas about 600-800 g seed is sufficient for planting of 1 ha by raising nursery in polythene bags or in plastic trays. The seed before sowing should be treated with thiram or captan @ 3 g/kg of seed to protect against seed and soil-borne diseases.
Sponge gourd is grown twice in a year in Northern India, once in spring summer (Feb-March), and then in rainy season (June July). However, in the Indo-Gangetic plains, for river bed cultivation, sowing is mainly done in October – November. In southern India sowing can be done. round the year due to mild winter. In hills of north India, the sowing can be done during April-May.
The method of planting depends upon the season, location and market demand. There are different methods of sowing i.e. flat bed, raised bed and raised pits. Generally, spring-summer crops sown in flat beds or on both side of the furrows of the bed and the vines are allowed to creep on the ground. However, sowing of rainy season crops should be done on raised beds or raised pits. Vines are trained over the trellis/ kniffen/bower system instead of allowing to creep on the ground. For preparation of the raised beds, deep furrows (50-60 cm width at 2-3 m distance) are made on well prepared fine tilth land. On both sides of the beds, 2-3 seeds/hill are sown at 60 cm spacing. In pit system, 45 x 45 x 45 cm size pits at 1.5-2.0 m width are made and filled with farmyard manure and topsoil in equal ratio and 2-3 seeds/pit at 2-3 cm depth are sown.
The river-bed cultivation is a kind of vegetable forcing, wherein cucurbits are sown in October-November. Trenches or pits having 0.6-0.75 m depth are made in east-west direction by maintaining 2-3 m spacing between the rows. Before the sowing of seed, the trenches are filled with farmyard manure or well-composted waste. In December-January, protection against frost/chilling winds is provided by erecting Sarkanda grass (Saccharum spp.), polythene sheets etc. placed at 75° angle on northern sides of the trench. Plants are irrigated with water-can until the taproot of sponge gourd plants touches the drenched regime below the ground. Fruits from the river bed cultivation are available 30-50 days earlier than the normally sown field crop, therefore, farmers fetch high price for their produce.
Growing in low tunnels
To get an early crop for the market the crop can also be started under the Ilow polyethylene tunnels raised over bow shaped bamboo or wires. The polythene is removed when the temperature outside becomes favourable.
Training/pruning (canopy management)
In small homestead gardens, the vines of sponge gourd are trained over the huts, walls, fencings, tree, etc. In commercial crops, vines are trained over the trellis/ kniffen/bower system. Vines of rainy season crops should be trained over the trellis/kniffen/bower system to produce high quality fruits. The crop is trained when the seedlings are about 10-15 cm tall. In northern India, generally crop is not trained during summer and the vines are allowed to creep on the ground.
After completion of emergence, two healthy seedlings should be retained on each hill. Excessive use of nitrogen, frequent irrigation and high temperature promote more vegetative growth, more male flowers and consequently, lower crop yield. The excessive vine growth can be pruned manually to promote higher female: male ratio. However, on commercial-scale vine growth can be kept in reasonable limit by adjusting fertilizer doses and frequency of irrigation. It is better to input all the fertilizer application just before the fruit set.
The requirement of manures and fertilizers in sponge gourd depends upon the soil type, system of cultivation and climatic conditions. of the growing region. If soil testing is not possible, well-decomposed farmyard manure @ 8-10 tonnes/ ha should be applied 10-15 days before sowing at the time of land preparation. Apart from this, 40-60 kg nitrogen, 30-40 kg phosphorus and 25-30 kg potash are needed for 1 ha. Before preparation of beds, whole dose of phosphorus and potash along with one-third of nitrogen should be applied on both sides of the channel. The remaining dose of nitrogen should be given in two split doses near the base of the plants. Use of 10 q/ha vermi-compost along with 45-50 kg nitrogen, 25-30 kg phosphorus, and 25-30 kg potash improves the fruit yield and quality of sponge gourd.
The sponge gourd crop is very sensitive to soil moisture. The irrigation requirement of the crop depends upon factors like soil type, temperature, humidity, wind velocity, wind direction etc. Irrigation water should be applied only through the furrows of the beds. The first irrigation is given two or three days prior to the sowing of seeds or if there is insufficient moisture in the soil during sowing then the first irrigation should be given just after sowing to accelerate the seed germination process. Irrigation should not flood the hills where seeds are sown to avoid surface crust formation during germination. The subsequent irrigations should be provided 4-5 days interval in summer. The water use efficiency can be doubled with the use of modern irrigation systems like drip and sprinkler than the conventional method.
Weeds can be controlled with two weedings/ hoeings before spreading the vines on the beds. First weeding should be done 15-20 days. after sowing and next weeding after 30-35 days of first weeding.
Diseases and pests
Important disease which affect sponge gourd are discussed here.
Downy mildew: Caused by fungus Pseudoperonspora cubensis. This is a very important disease of sponge gourd and other cucurbits. It is prevalent in areas of high humidity, especially when summer rains occur regularly. Early symptoms appear on the upper surface of the leaves as angular yellow spots and grayish downy growth of fungus develops on lower surface of leaves. The leaves subsequently wither and die.
Powdery mildew: This is caused by fungus Sphaerotheca fulginea and Erysiphe cichoracearum. The fungus affects all parts of the plants, forms a white to dirty grey powder coating on leaves, stem, and other succulent parts of the plant during hot and dry weather condition. The severely attacked leaves become brown and shriveled, and premature defoliation and death of the vines are occurred. The fruits get undersized and deformed. Remove the weeds around the field. Diseased debris should be destroyed by burning.
Collar rot: This is caused by fungus Rhizoctonia solani and it is also known as rhizoctonia root rot. It causes mortality at pre-and post-emergence stages of seedling. The stem shows brown to dark brown lesions at the level of soil surface, which eventually kills the plant. Damping-off of seedlings also takes place. The older plant is less susceptible than the younger ones. Follow up crop rotation with non-host crops.
Sponge gourd yellow mosaic: The yellow mosaic disease of sponge gourd is caused by tomato leaf curl New Delhi virus (ToLCNDV). The disease may cause yield losses up to 100% under epidemic conditions. The disease is characterized by yellow spots appearing on newly emerging leaves, followed by a mosaic appearance and upward curling of the upper leaves. In severe attack, leaves of the plant are small, mottling and distorted, and misshapen fruits are produced. The virus is transmitted through sap as well as vector whitefly (Bemisia tabaci), in semi-persistent manner under natural conditions. To check the diseases – do not plant the sponge gourd next to old fields of tomato, pepper or tobacco; avoid growing of sponge gourd near the field of brinjal, wild cucurbits and cotton; 20 days before sowing/transplanting of sponge gourd in the field, grow double row of sorghum or bajra or Johnson grass or corn or elephant grass as border crop around the main field; follow proper space between the rows/ plants so as to avoid spreading of disease as it is sap transmissible. Need-based foliar spray of fungicides is recommended.
Important pests which affect sponge gourd are discussed here.
Red pumpkin beetle (Raphidopalpa faveicollis): The insect is brightly coloured elongated small beetle of orange-red colour. The beetles attack the crop at seedling stage and feed on cotyledonary leaves making holes. The crop is destroyed absolutely and only a vein skeleton is left behind when the infestation is very severe. Early sowings may avoid the attack of red pumpkin beetle on crop to an extent at seedling stage. The grubs of this beetle attack on the roots of the plants under the soil. During the severe attack, plants show wilting and ultimately die. The management of the problem is possible by deep summer ploughing expose the pupae for desiccation and predation by birds. During the infestation recommended pesticides should be used.
Whitefly (Bemisia tabaci):Whiteflies are polyphagous insects. There are 11-15 generations in a year. Both the nymphs and adults suck the sap and also secrete honeydew on which black sooty moulds develops that reduce the photosynthesis of the plants. Apart from direct feeding damage, it also acts as vector to transmit the tomato leaf curl New Delhi virus, which causes yellow mosaic disease of sponge gourd.
Aphid (Aphis gossypi and Myzus persicae) and jassid (Empoasca sp.): These small (tiny) insects cause damage from April to June by sucking cell sap from tender foliage. In young stage, cotyledonary leaves crinkle and in severe cases plants wither. In the grown-up vines, the leaves turn yellow, and consequently affected plants lose their vigour and yield.
Fruit fly (Dacus cucurbitae):This is a serious. insect whose maggots cause severe damage to young developing fruits. The adult flies puncture tender fruits and lay eggs below the epidermis of fruit skin. The eggs hatch into maggots and they feed inside the fruits and spoil them. The fruit fly attack is more severe when humidity is high, especially after the summer rains. Raise maize plants at 8-10 m distance as a trap crop. Collect the infested fruits and destroy them by burying deep into the soil. By deep summer ploughing expose the pupae for desication and predation by birds. Apply poison baits and recommended pesticides.
Blister beetle (Mylabris phalerata, M. pustulata): Adult beetles can easily be recognized by their bigger size and black colour elytra with two wavy orange spots on it. Adult beetles are highly polyphagous and the only damaging stage of this pest that feeds on flower and flower buds of sponge gourd. In severe infestation, they eat almost all the flowers and thereby reduction in fruit set occurs. Peak infestation is usually from August to November in Varanasi region. Collection and destruction of the adult beetles is advisable for management. During manual collection, hand gloves should be worn as precautionary measure to get rid of from the adult beetles. Need based application of neem seed kernel extract (NSKE) 4% along with sticker (0.5 ml/lit of water) recommended.
Nematodes (Meloidogyne incognitaand Meloidogyne javanica): Most of the cucurbits are highly susceptible to nematode infestations. In sponge gourd, Meloidogyne incognita is more severe than the Meloidogyne javanica. The crop infested with nematodes show reduced growth, varying degree of chlorosis, leaves become yellow, wilting of foliage and sometimes death of plants. The nematodes live in soil, thus, cultural practices are effective to control them. Expose the soil to sun through frequent deep summer ploughing. Follow long duration crop rotation by rotating the crop with non-host crops (mustard or onion or garlic) for 2 years. As organic amendments, apply neem cake @ 500 kg/ha for the control of nematode.
Harvesting and post-harvest management
The fruit growth of sponge gourd is faster and it attains optimum size within 5-7 days after anthesis. Harvest the fruits when they are tender and seeds inside fruits are still soft. Harvesting should be done. every 3 or 4 days and delay in harvesting of fruits leads to fibrous fruits with hardened seeds and unfit for consumption.
The yield of fruits depends upon the variety, growing season, soil type, nutrition, and cultural practices followed for raising the crop. On an average, sponge gourd bears 15-30 fruits/vine and yields 12.5-20 tonnes/ha. The number of fruit per vine and length of fruit determine the yield of sponge gourd.
To avoid any kind of loss, care should be taken during harvesting, pre-cooling, grading, packaging, and transportation. Grading of fruits should be done according to size, shape and colour and it should be free from insect-pests, particularly fruit fly, and disease infestation. During the grading, care should be taken that the graded fruits should not have any injuries. Fruits should be properly cleaned before packaging. The fruits are packed in mulberry or bamboo baskets, or in plastic crates with proper packaging to prevent injuries in transit. The fruits are marketed in local as well as in distant markets.
Harvested fruits of sponge gourd have short storage life of 2-3 days under ambient temperature. However, it can be stored for few weeks under 10°C and 60-70% RH.
For seed production, sponge gourd requires 1,000 m isolation distance between two varieties of same species. If there is lack of proper isolation distance, pure seeds can be produced through selfing. The raising of seed crop is similar to the fresh fruit crop, except that of difference in harvesting stage of the fruit. The undesirable or off-type plants must be removed. The average seed yield of sponge gourd is 200-300 kg/ha. Fruits are allowed to physiologically mature on the plants and seeds are extracted when fruits are dry. After cleaning and drying seeds should be packed in aluminum foil packets and stored at low temperature and low humidity.