Diseases of Cucumber and their effective control to avoid crop losses

Fungal Diseases

•       Damping off , the causal agent is Pythium, Phytophthora , Rhizoctonia

•       Anthracnose he causal agent is Colletotrichum orbiculare & C. lagenarium

•       Downy mildew he causal agent is Pseudoperonospora cubensis

•       Powdery mildew he causal agent is Erysiphe cichoracearum

•       Wilt/Foot rot he causal agent is  Fusarium oxysporum

Bacterial Diseases

•       Bacterial wilt he causal agent is Erwinia tracheiphila

•       Angular leaf spot he causal agent is Pseudomonas syringae

Viral diseases

•       Cucumber Mosaic  he causal agent is Virus

•       Squash Mosaic he causal agent is Virus

•       Watermelon he causal agent is Mosaic Virus

•       Zucchini Yellow Mosaic he causal agent is Virus

•       Papaya Ring Spothe causal agent is  Virus

Nematode Diseases

Root-Knot Nematode (Meloidogyne incognita)

Damping-off

Disease development factors

The disease will spread if  favors warm, humid conditions

 

Control Measures:

•       Soil solarization may be helpful

•       Sanitation, prompt removal of symptomatic plants

•       Seed treatment with Thiophenate methyl or Carbendazim @ 2 gm / Kg seed

foFor more Click

Anthracnose

Leaf lesions are more or less circular and usually start near the veins

Picture shows leaves ranging from healthy (top left) to completely dead (lower right).

Severe leaf infection can result in loss of many leaves; a situation that decreases the photosynthetic activity of the plant

Infection points on the fruit are circular and sunken.  Internal infection discolors the fruit and makes it unsuitable for market

 

Control Measures:

u      Deep tillage immediately after harvest

u       Plant only pathogen-free seed

u      Crop rotation - At least 2 years between cucurbits

u      Seed treatment with Thiophenate methyl or Carbendazim @ 2 gm / Kg Seed

u      Spray with Topsin-M or Carbendazim @ 2.5 gm/lit. water

Downy mildew

•       Small yellow spots on the upper surface of older leaves.

•       Lesions expand and in time become necrotic

•       Yellow spots on the upper side of leaves

•       Fluffy purplish mildew on underside of leaves

 Control Measures

•       Avoid over irrigation

•       Avoid overcrowding of plantings

•       Crop rotation.

•       apply appropriate fungicide     

Product	Active ingredient	Dose/100 lit.water
Champion 77% WP	Copper Hydroxide	200 gm
Folio Gold 440 SC	Chlorothalonil	1000 ml
V-Nurse 70% WP	Fosetyl aluminium + Mancozeb	330 gm
Ridomil Gold 68% WG	Mefenoxam +Mancozeb	250 gm
Feast-M 72% WP	Metalaxyl+ Mancozeb	250 gm
Metacarb 25% WP	Metalaxyl + Propamocarb	330 gm
Proctor 25% EC	Difenoconazole	200 ml
T-Zole 25%	Tebuconazole	250 ml
Score 250 EC	Difenoconazole	200 ml

Powdery Mildew

•       Talcum like powdery growth on leaves, stems

•       Infected leaves and stems wither and die

Control Measures

•       Avoid crowding of plants

•       On the appearance of disease spray with

Product	Active ingredient	Dose/100 lit.water
Score 250 EC	Difenoconazole	200 ml
Contaf + 5.1% SC	Hexaconazole	200 ml

Wilt/Foot rot

•       Fungus enters plant through roots and causes rotting of seedling stems at soil line

•       brown lesions on one side of stem; discoloration of tissue inside vine

Control Measures

•       Crop rotation as long as possible between plantings for 4 to 8 years.

•       Soil solarization of the sick field.

•       Seed treatment with Thiophenate methyle or Carbendazim @ 2 gm / kg of seed.

•       Use of Trigopopak, Aspergopak along with wheat straw in the soil helpful in controlling the disease. 

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Bacterial wilt

•       Slimy dull green patches on leaves and stems;

•       leaves appear dark green;

•       dark discoloration on leaves and stems;

•       Infected plants will ooze strings of bacterial exudate

•       rapid plant death

 Control Measures

•       Control cucumber beetle populations on plants;

     (hand-pick adult beetles and destroy)

•       Soil and foliar application of appropriate insecticides may help to control populations

Angular Leaf Spot

•       Leaf lesions bounded by veins - angular appearance

•       Fruit lesions small, circular, water-soaked spots

•       internal rot of fruit

 Control Measures

u      Rotate crops - 2 years minimum between cucurbit crops

     Irrigation to avoid prolonged wetting of foliage and fruit

u       Season-ending sanitation

u        Spray with Streptomycin sulphate @ 1 to 2 gm/lit.water 

Root-Knot Nematode

Control Measures

•       Green house steaming

•       Application of Carbufuran @ 1.5 kg/ha. Below the seed level also reduces the attack of Meliodogyne incognita

Application of Pasteuria penetrans Very effective against Vegetable Root knot Nematode

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