Watermelon problem: Wilting or collar rot?

Watermelon    None Given

Its looks some type of wilting or collar rot, and it's very severe in the field. Any ideas?

Posted by: Samiullah (1 point) Samiullah
Posted: April 8, 2016


The wilting and rotting in watermelon may occur due to following pathogens
1. Black root rot of watermelon caused by Thielaviopsis basico
2. Crown and foot rot of watermelon caused by Fusarium solani
3. Fusarium wilt of watermelon caused by Fusarium oxysporum f.sp niveum

It is very important to know the causal organism to recommend any control measures. To diagnose further please provide the following information,
a. Symptoms on leaves other than wilting
b. Is wilting one sided?
c. Is there any discoloration in vascular tissue? (Hard to see from your image)
d. Percent of field infected?
e. Recent agronomic practice carried.
f. Weather conditions etc.

Posted by: Dr. Ravishankar Narayana (11 points) Dr. Ravishankar Narayana
Posted: April 8, 2016

Samiullah commented,
20 percent damage of the field in 2 to 3 days.No discoloration of tissues. No mechanical practice in the field. Irrigation practice going on day by day
over 4 years ago.

Dr. Ravishankar Narayana commented,
It looks like crown and root rot disease. The main symptoms are wilting of leaves followed by wilting of vines and plant death. The vascular tissue are not discolored. Stem shows dark reddish to brown surface discoloration with restriction of growth near soil line. The root cortex of the infected plants become yellow, brown and necrotic. The infected stem near the soil surface is covered by white/pink fungal mycelium. Management: There are fungicides available to control the disease but they are not effective in controlling disease and not feasible to use at this stage. For next growing season follow this methods 1. Remove the infected plants and burn them 2. Deep summer ploughing and mulching with black plastic reduces Fusarium population 3. Follow crop rotation (grow non cucurbit crops for atleast 3 to 4 years) 4. Apply biocontrol agent like Trichoderma viridae or Trichoderma harzianum to soil. 5. The disease spreads through irrigation water. If possible use drip irrigation system instead of flooding method.
over 4 years ago.

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