Cucurbits

• Cucurbits are the popular name of the family Cucurbitaceae, commonly known as the gourd family.
• They are widely distributed in the tropics and warm temperate regions of the south, southeast, and East Asia, Africa including Madagascar, central and South America.
• The family is represented by about 120 genera and 800 species. Cucurbits are mostly climbers and trailers and are rarely woody and arborescent.
• They are characterized by the inferior ovary and parietal placentation.

• The most common uses of cucurbits are vegetables and fruits.
• Most of the cucurbits are monoecious in nature.
• Pointed Gourd, Spine Gourd, and Scarlet Gourd are dioecious in nature.
• Fruit is essentially an inferior berry and is called ‘Pepo’ due to its hard rind when mature.
• Cucurbitacin is a toxic substance present in cucurbits and it is responsible for bitter tests in most cucurbits.
• Cucurbitacin is a tetracyclic triterpins having extensive oxidation level. Fruits and roots have more concentration than leaves. Pollen grain also carries a fairly good amount of bitter principle.
• Cucurbits are mostly annual plants but some are perennial like chow-chow, pointed gourd, and ivy gourd.
• The fruits of all cucurbits are many-seeded except chow chow.
• In Cucurbits coiling tendrils arise from the leaf base but are absent in bushy cucurbites.
• In cucurbits, coarse hairs are present on the stem.

River bed cultivation of a number of cucurbits is economical and known as Daria cultivation. The river beds of big rivers used for cucurbit cultivars are Ganga, Yamuna, Saraswati, Narmada, Sutlej, Krishna, Kaveri, Godavari, Mahanadhi, Sabarmati, Bramhaputra, etc. Cucurbits are popular because they are easy to grow. They do not require high inputs. They can be grown on even soils of marginal fertility. They are useful to prevent soil erosion.

Uses of cucurbits

• Vegetables: Bitter Gourd, Ridge Gourd Sponge Gourd, Round Gourd, Pointed Gourd, and Pumpkin are used as vegetables. Immature fruits of Musk melon are also cooked as vegetables only in some areas.
• Salad: Excellent salad is made from Cucumber and Little Gourd
• Table Purpose: Muskmelon, Water Melon, Cucumber.
• Pickle: Cucumber, Little Gourd, and Bitter Gourd are used for making pickles.

Disease Management in Cucurbits

1. Powdery Mildew (Erysiphe cichoracearum):

Appears white round spots on the undersurface of older leaves. Spot enlarges and increases in number, appear on the upper surface of leaves and eventually covers both surfaces.

Control

• The field kept free from weeds
• Infected plant parts are destroyed.
• Spraying the crop with 0.1% Bavastin or Karathane.

2. Downy Mildew (Pseudopernospora cubensis):-

Appears yellow to reddish brown spots on the upper surface of the leaves. The lower surface of the spot is covered with pink to purple fungal cottony growth. In severe attack leaves become turn yellow and start drying. Sometimes plant growth also stops.

Control:

• Follow crop rotation.
• The destroyed residue after harvesting or the end of the crop.
• Spraying with mancozeb @ 2.5kg / 1000 litre water.

3. Fruit Rot (Choanephora cucurbita or Pythium spp.):- This disease more at high humidity and temperature. The first symptoms shown on flowers they are the rotten and cottony mass of purplish to black colour appear on it. In the later stage, fruits are affected they also start rotten.

Control:

• Manage proper drainage facility.
• Giving the support to climb the vine.

4. Anthracnose (Colletotrichum lagenerium):-

This disease is spread in the field through irrigation, agricultural equipment, and insects. These disease spots cover entire leaf area and are dry. In severe attacks oblong to round water-soaked spots appear on fruits. They collapse and fruits start rotting.

Control:

• Follow crop rotation.
• Kept field weed free.
• Seeds are treated with Thiaram, Carbendazime @ 2.5 gm/ Kg

5. Witches Broom (Mycoplasma): –

Mostly occurs in bitter gourd. In the early stage of growth plant growth is stunted and the main symptoms of this disease are malformation and proliferation of axillary buds. Leaf size also reduces and the plant looks like a ‘witches broom’. Many times, bear a small or a greater number of flowers but there is no fruit set.

Control

• Apply 1.5 kg/ha carbofuran at the seed sowing time
• Spray monocrotophos (0.05%) or Phosphamidon (0.05%) at the 4-6 leaf stage and repeated at 10 days intervals to control the vector.
• Spraying of Oxytetracycline hydrochloride solution (500 ppm) at weekly intervals.

6. Green Mottle Mosaic (Virus): –

This is a common disease of cucumber. Symptoms are small irregular yellowish spots/patches seen on the leaves. Some leaves show vein clearing in one or two lobes of the leaf. Young developing leaves are completely distorted and malformed with a considerable reduction in their size. The virus is transmitted by seeds as well as aphids.

Control:

• Seed treated with Thiaram and captan 2g / kg seed before sowing.
• Spraying the crop at the initial stage with Monocrotophos (0.05%) or Phosphamidon (0.05%) at 10-day intervals prevents aphid vectors.

Insect pest Control

1. Red pumpkin beetle (Aulacophora foveicollis): –

Yellowish-brown beetles feed on leaves and make them like sieves. Sometimes cut plant stems to ground level.

Control

• Spray Quinalphos 0.05% at 10 days intervals.

2. Fruit Fly (Bactocera cucurbitae):-

This is a serious pest of cucurbits. Pest puncture the young fruits and lay eggs below the skin.

Control: –

• Spray fenthion 0.05% with jaggery salutation.

3. Thrips (Thrips tabaci): –

Thrips suck the sap from tender parts and leaves and curl the leaves upward.

Control:-

• Spray the plant with Dematon 0.05% or monocrotophos (0.05%).