Gourd

Description

Gourds are annual trailing or climbing vines in the family Cucurbitaceae grown for their fruit of the same name. The two most commonly grown types of gourd are Lagenaria species and Cucurbita species. Gourd plants produce long vines with long-stemmed, large, oval or triangular lobed leaves. The Cucurbita gourds produce yellow flowers and unusually shaped fruit which can be smooth or warty, plain or patterned. The Lagenaria gourds produce white flowers and smooth, knobly or ridged fruit which can range in size from 7 cm (3 in) up to 1 m (3 ft). Gourd vines are capable of climbing over 3.5 m (12 ft) and as annual plants, survive only one growing season. Gourds may also be referred to as dudi, cucuzzi, spaghetti squash or calabash and are believed to have originated in Africa.


Uses

Young gourds can be cooked and eaten as a vegetable while the mature gourds are used to make decorative items such as bottles, containers and utensils. In the US, gourds have become a very popular household decoration in the Fall.


Propagation

Gourds are warm season annuals and grow optimally in hot and humid climates, at temperatures ranging from 21–27°C (70–85°F). The plants can grow in a variety of soils but will grow best in a well draining, fertile soil and prefer sandy loam or clay loam with a pH between 6 and 6.7. Gourds are normally propagated from seed and should be planted at a depth of 2.5 cm (1 in). In addition, sowing seed in a mound of soil will warm the seed quicker and promote germination. Plants should be spaced 90–180 cm (35.4–70.8 in) apart, leaving 180–240 cm (70.8–94.5 in) between rows. A trellis will provide support for larger varieties and will save space by allowing the vines to climb from the ground.


Common Pests and Diseases

Angular leaf spot Pseudomonas spp.

Symptoms
Angular brown spots with yellow edges; water soaked spots; holes in leaves where older spots have dried out; water soaked spots on stems, petioles and fruit
Cause
Bacteria
Comments
Spread through infected seed, splashing rain, insects and movement of people between plants; bacterium overwinters in crop debris and can survive for 2.5 years
Management
Use disease-free seed; do not grow plants in field where cucurbits have been grown in the previous 2 years; protective copper spray may help reduce incidence of disease in warm, humid climates; plant resistant varieties

Bacterial leaf spot
Xanthomonas spp.

Symptoms
Small, angular yellow-brown spots with yellowish edges on foliage; fruit rot
Cause
Bacteria
Comments
Spread via infected seed; disease emergence promoted by high temperatures
Management
Avoid overhead irrigation

Alternaria leaf blight Alternaria cucumerina

Symptoms
Brown lesions with yellow edges on the leaves; lesions forming concentric rings of brown and yellow
Cause
Fungus
Comments
Disease emergence favors warm, rainy weather conditions
Management
Rotate crops away from cucurbits for at least 2 years; plow crop debris deeply into soil after harvest; apply appropriate protective fungicides regularly; avoid overhead irrigation

Anthracnose Colletotrichum orbiculare

Symptoms
Tan to brown lesions with dark spots inside on leaves and petioles, main stem and fruit
Cause
Fungus
Comments
Disease favors warm weather
Management
Plant resistant varieties; use only certified seed; apply appropriate protective fungicides; rotate crops every year

Downy mildew Pseudoperonospora cubensis

Symptoms
Angular brown lesions on upper side of leaves; purple to gray spores and gray mold on underside of leaves; brown leaves; dead leaves that remain attached
Cause
Fungus
Comments
Disease favors cool, humid weather
Management
Do not overcrowd plants; avoid overhead irrigation, water plants from base; apply appropriate fungicide

Gummy stem blight Plectosporium tabacinum

Symptoms
V-shaped yellow to brown areas on stem; cracked dry areas on stem; lesions leaking a sappy material
Cause
Fungus
Comments
Disease may be seed-borne
Management
Use disease free seed; treat seeds prior to planting; rotate crops every 2 years

Phytophthora fruit and crown rot Phytophthora capsici

Symptoms
Sudden wilting of plants; brown lesions on stems and roots; rotting fruit; stunted plant growth; downy growth may be present on lesions during periods of high humidity
Cause
Oomycete
Comments
Disease emergence favored by heavy rainfall and poorly draining, waterlogged soils
Management
Do not plant in poorly draining soils; avoid over-watering plants; rotate cucurbits with non-susceptible plants for a period of at least 3 years

Powdery mildew Sphaerotheca fuligniea

Symptoms
Powdery, white spots on the undersides of leaves; yellowing leaves
Cause
Fungus
Comments
Disease emergence favored by dry weather and high relative humidity
Management
Plant in sites with good air circulation and sun exposure; do not overcrowd plants; sanitize equipment regularly

Scab Cladosporium cucumerinum

Symptoms
Angular brown lesions on leaves confined by small veins; pale green and water soaked lesions; holes in leaves from dried out lesions; lesions may also be present on petioles, stems and fruit
Cause
Fungus
Comments
Fungus survives in soil on crop debris; may be seedborne; disease emergence favored by wet weather and temperatures below 21°C (69.8°F)
Management
Rotate cucurbits with non-susceptible crops for a period of at least 2 years; plant only in well-draining soils; spray plants with appropriate protective fungicides

Western striped cucumber beetle (Western spotted cucumber beetle, Banded cucumber beetle) Acalymma vittata
Diabrotica undecimpunctata
Diabrotica balteata

Symptoms
Feeding damage to leaves, blossoms and stems
Cause
Insect
Comments
Beetles overwinter in soil and leaf litter and can transmit bacterial wilt
Management
Monitor new planting regularly for signs of beetle; apply appropriate insecticides

Squash vine borer Melittia cucurbitae

Symptoms
Plant or runner wilting suddenly; entry holes in vines; sawdust like material at the base of the plant; may be yellow to brown feces coming out of holes
Cause
Insect
Comments
Insect overwinters in soil as larvae or pupae and adults emerge in spring; adults lay eggs on leaves and larvae burrow intro stems to feed
Management
Apply appropriate insecticide if eggs are found on leaves; plow plants into soil after harvest