Tag: post-harvest diseases

• Papaya is susceptible to various fungal, viral, and post-harvest diseases.
• Diseases affect yield, fruit quality, and marketability.
• Effective management requires accurate diagnosis and integrated approaches.

• Powdery Mildew: Oidium indicum, Oidium caricae, Leveillula taurica
• Leaf Blight: Corynespora cassiicola
• Damping-Off: Pythium aphanidermatum, Rhizoctonia solani
• Foot Rot: Pythium aphanidermatum
• Anthracnose: Colletotrichum gloeosporioides

• Speckled, water-soaked spots on leaf underside.
• Powdery patches enlarge, covering leaves.
• Leaves become chlorotic, distorted, and fall prematurely.

Management:

• Clean cultivation and balanced fertilization (increase K, reduce N).
• Dusting sulfur (30 g/10 L water) at symptom onset.
• Spray Triadimefon (0.1%) or systemic fungicides (Bayleton, carbendazim) at intervals.

• Water-soaked patches at stem base, girdling stem.
• Tissues turn brown/black and rot; terminal leaves yellow and wilt.
• Fruits shrivel and drop; plant may topple and die.
• Roots deteriorate; bark appears dry, honeycomb-like.

Management:

• Use well-drained nursery beds; remove and destroy diseased seedlings.
• Apply Trichoderma viride (15 g/plant) with FYM at planting.
• Seed treatment with captan (4 g/kg) or chlorothalonil (2 g/kg).
• Drench stem base with COC (0.25%), metalaxyl (0.1%), or Bordeaux mixture (1.2%).

• Gray to brown spots with dark margins and yellow halo on leaves.
• Necrotic areas form as spots coalesce.
• Fruits develop light spots that enlarge, become dark brown, and may show concentric rings.
• Premature fruit drop common.

Management:

• Remove and destroy affected fruits.
• Harvest fruits at maturity.
• Spray copper oxychloride (0.3%), carbendazim (0.1%), or thiophanate-methyl (0.1%) every 15 days.
• Hot water or fungicidal wax treatment for export fruits.

• Papaya Mosaic Virus (transmitted by Aphis gossypii)
• Papaya Leaf Curl Virus (transmitted by Bemisia tabaci)
• Papaya Ring Spot Virus (PRSV; transmitted by aphids)

• Mild mosaic pattern and deformation in young leaves.
• Dark green blister-like patches on yellowish-green leaves.
• Leaf vein clearing, downward curling, and shortened petioles.

• Severe curling, crinkling, and deformation of young leaves.
• Vein clearing and thickening; twisted petioles.
• Stunted growth, reduced yield, and possible defoliation.

• Prominent mosaic and chlorosis on leaves.
• Oily streaks on petioles and trunk.
• Distorted young leaves; concentric rings and C-shaped markings on fruits.

• Use disease-free seedlings for planting.
• Rogue and destroy infected plants promptly.
• Control vectors with insecticides (monocrotophos 0.05%, dimethoate 0.2%, metasystox 0.1%).

• Macrophomina Rot: Macrophomina phaseolina
• Rhizopus Rot (Soft Rot): Rhizopus stolonifer
• Phomopsis Rot: Phomopsis caricae
• Anthracnose: Colletotrichum gloeosporioides

• Small water-soaked spots on fruit surface.
• Spots deepen, causing internal rot and sclerotia formation.
• Inner tissues turn brownish-black with dark mycelial growth.

• Irregular water-soaked lesions on injured fruits.
• Lesions covered with whitish fungal growth, turning dark brown.
• Fruit becomes watery, emits foul odor, and infection spreads rapidly.

• Initial water-soaked spots become sunken and dark brown to black.
• Spots may be surrounded by white, raised tissue.
• Infected area becomes soft and pulpy.

• Harvest fruits at proper maturity and during cool hours.
• Dipping fruits in TBZ (1000 ppm) or benomyl (20 ppm) reduces storage decay.
• Dusting fruits with benzoic acid (0.1%) in kaolin reduces rotting.

• Adopt clean cultivation and use disease-free planting material.
• Monitor and manage vectors for viral diseases.
• Apply recommended fungicides and biological agents for fungal diseases.
• Practice proper post-harvest handling to minimize losses.