satg WATERMELON CULTIVATION DISEASES PESTS
Contents Cultivation Climate Requirements...4 a. Temperature...4 b. Exposure...4 Land Preparation...5 A. Soil Requirements...5 B. Propagation...5 Planting...6 Mulch...7 Fertilizer Application...8 Irrigation...9 Weed Control...9 Crop Harvesting...10 Storage...10 Diseases Damping-off disease...12 Powdery Mildew...12 Angular Leaf Spot...13 Pests Aphids...15 Whiteflies...15 Epilachna Beetles...16 Flea Beetles...16
30 cm 1m FURROW CULTIVATION 3
STEP 1 Climate Requirements Temperature Watermelons are sensitive to very cold and very hot temperatures. The most appropriate temperature to grow watermelon is between 18 C and 35 C. Temperatures above 35 C or below 18 C will result in poor growth or slow maturation Exposure Exposure to full, direct sunlight is necessary for the crop. For optimal growth, a minimum of 8-10 hours of direct sunlight per day is needed. healthy poor X 4
STEP 2 land preparation Soil Requirements: Watermelon grows well on sandy loam soils that are well drained, and slightly acidic with a ph of 6.0-6.5. Propagation The best soil temperature for seed germination is 25-32 C. Prepare the field by plowing and harrowing thoroughly. Remove any other plant remains. Shape the land into beds which allows furrow irrigation of seedling and drainage after heavy rain. Furrows should be 2m apart and the beds should be 2m wide and 20-30cm high. Note: If the soil is not warm enough (at least 21 C), place a black plastic film covering most of the soil beds to heat the soil. This also helps prevent weeds and pests. 2m furrow 20-30 2m BEd 5
STEP 3 Planting mixed compost Mix plenty of compost or manure (at least 1 shovel full) into each planting hole. Plant two-three seeds per hole, 3-4 cm deep into the soil. Water well! 3-4cm Separate the seeds 60-90 cm apart when planting into the soil. 60-90cm 60-90cm Within a couple of weeks the seed should show signs of germination. When two sets of leaves are showing, remove the weaker ones and leave the strongest seedlings to grow. 6
STEP 4 Mulching When planting watermelons, apply mulch as it helps retain the moisture of the soil. It is recommended to use organic mulch, such as: Straw Hay Chopped leaves Mulching also provides food for the millions of microorganisms in the soil thus making the soil more nutritious for the plant. 7
STEP 5 Fertilizer application In order for resourceful development, watermelons need nitrogen, phosphorus and potassium-based fertilizers. The maximum amount of these fertilizers required is 60 pounds/ha. Fertilizer should contain several essential nutrients: A general application of Urea is recommended before the time of planting. Nitrogen-based fertilizers such as ammonium sulfate or ammonium nitrate are extremely beneficial in regions such as Somalia. 8
STEP 6 Irrigation Remember to water plants at 3 critical points: 1. Immediately after planting to allow fast and even emergence. 2. At early bloom, to prevent poor, underdeveloped fruit. 3. During fruit development to ensure good melon size. note Do not over water as it will decrease fruit development which results in blossom-end rot, and fruit splitting. Weed Control: Hand Hoeing and Mechanical cultivation are the best methods to control weeds. Using cultivation machines to prune the vines and roots decreases the development of watermelon and reduces yield. Chemicals such as Metam Sodium can also be applied to suppress weeds. 9
STEP 7 Crop harvesting note It is important to consider that different watermelon types take different lengths of time to fully mature. For smaller types, the length of time generally ranges from 60-90 days, and larger watermelons can take 90-120 or more days to fully mature. If you are hand pollinating your watermelon flowers, you may want to note that the flowers will be ready for pollination within 2-3 weeks of planting seeds, and the fruit growing stage lasts for 1-4 months. Thumping the watermelon determines the level of maturity A metallic ringing means the fruit is immature. A dull or muffled sound means the fruit is mature/over mature. It is advisable to cut open a few fruits from various areas in the field to check maturity before harvesting commences. Storage: Watermelons can survive in storage with temperatures between 11-15 C for about 2-3 weeks. Optimum humidity levels are between 85%-90%. Higher humidity may lead to stem-end rot. Keeping watermelons at room temperature for up to a week can improve both color and flavor. 10
DISEASES 11
Damping-off disease Symptoms and Damage: Diseased seedlings undergo rotting and death of infected roots. A white, cotton growth appears on infected tissues. Disease Management: Mechanical control -Use certified disease-free seeds. -Avoid fields with damping-off history. -Leave wide spacing between plants. -Avoid over-watering Chemical control -Plant only fungicide-treated seed. -Drench soil with copper hydroxide. powdery mildew Fungal disease affecting a wide range of plants. Symptoms and Damage: -Whitish powdery growth on upper leaf surface. -Fungal growth on surface. -Severely attacked leaves turn brown, dry and brittle. Disease Management: Mechanical Control -Use resistant varieties, if available. -Destroy weeds. 12
Angular Leaf Spot Symptoms and Damage: -Watery spots on leaves with variable sizes. -Initially, spots are water soaked. -Affected leaf dries and shrinks. -Fruit spots are small, nearly circular and superficial. Disease Management: Mechanical Control -Use certified disease-free seed. -Practice crop rotation. -Avoid run-off water from nearby overhead irrigation. Chemical Control Limit the soil where it is acidic. 13
PESTS 14
Aphids Aphids are small bugs that suck the sap from plants and can cause extensive damage to crops. Symptoms and Damage: -Suck sap from plants. -Leaves become curled and twisted. -Aphids also transmit virus diseases. Pest Management: Chemical control Treat plants with selective insecticides (e.g. pymetrozine, pyrimicab) when you notice aphids. Whiteflies Whiteflies are small white bugs that damage plants by feeding on the sap and coating them with honeydew. Symptoms and Damage: -They suck plant sap. -Excrete honeydew where moulds grow, which may affect plant Pest Management: Mechanical Control -Control weeds. -Conserve natural enemies such as lacewings, bigeyed bugs, and minute pirate bugs. Chemical control -Spray with neem products -Spray with a selective insecticides (e.g. buprofezin) 15
Epilachna Beetles Epilachna beetles are small yellowish beetles with a number of black spots on their wing cases. Symptoms and Damage: -Adults and larvae feed on leaves leaving a fine net of veins -Damaged leaves shrivel and dry up -Young plants can be entirely destroyed Pest Management: CHEMICAL CONTROL -Spray neem extracts. Weekly application reduces the damage of the beetle significantly. Flea Beetles Flea beetles are black, brown or metallic blue-green beetles that are 1.5 to 3mm long and are known to chew holes in leaves. Symptoms and Damage: Adults chew small round holes (shot holes) in leaves. These pests are most damaging to seedlings. Pest Management: Mechanical Control -Thick mulches -Floating row covers CHEMICAL CONTROL Spray botanicals or other alternative products 16 Recommended products: Neem Rotenone Pythrin Garlic Insecticidal soap is also reported
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