Garlic (Allium sativum)

Downy mildew (Perenospora destructor)

Symptoms

  • In systemic infection occurs when the plants are raised from the diseased bulbs, the seedlings and plants remain stunted, become distorted and pale green with downy fungal growth.
  • In localized infection, symptoms appear on the surface of leaves or flower stalk as violet growth of fungus, which later becomes pale greenish yellow and finally the leaves or seed stalks collapse.

Management

  • Select healthy bulbs for seed production.
  • Follow crop rotation for 3-4 years with non-host crop.
  • Crop sanitation: Dispose properly the infected crop debris and refuse heaps of garlic culled from storage.
  • Avoid late planting, poor drainage, higher doses of fertilizers and frequent irrigation.
  • Use resistant varieties.
  • All weeds serving as collateral host of the fungus should be removed and destroyed.
  • Onion bulbs meant for seed crop should be exposed to sun for 12 days to destroy the fungus.

Chemical Control

Sl.No Generic Name Trade Name Color code Dosage/litre Knapsack Sprayer (Capacity 10L) Recommendation Remarks
Dosage/acre (200 L) Dosage/hectare (500 L)
1 Potassium phosphonate 40 SC Akomin Green 4 ml/litre of water 40 ml 800 ml 2000 ml -
2 Mancozeb 75 WP Devidayal M-45, Dhanuka M 45, Dhanuka M-45, Dithane, Dithane M-45, Hilthane, Hindustan M 45, Indofil M 45, Izeb M-45 Manzate, Luzen-45, Macoban, Macoban M-45, Mancosaan, Mancosaan M-45, Maneb Manzane, M-Guard, Savour M 45, Tata M-45 Eurofil-NT, Uthane M-45, Veera, Zinthane Green 3 g/litre of water 30 g 600 g 1500 g -
3 Copper hydroxide 77 WP HiDice, Kocide 101 Blue 1 g/litre of water 10 g 200 g 500 g -
4 Copper oxychloride 50 WP Bensaan, Blitox, Blue copper, Bluetrox, Copter, Cupramar, Cuprina, Dhanucop, Fytolan, Fytox, Fytran, Fytolan, Hilcopper, Killex copper, Maincop Dhanucop, Star cop, Tagcop, Trucop Blue 2 g/litre of water 20 g 400 g 1000 g -
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Extremely Toxic
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Highly Toxic
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Moderately Toxic
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Slightly Toxic