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points
What kind disease is this?

Watermelon    None Given

Many of fruits have this abnormal shape and some of them has got this yellow colour on side. They are soft on this spots. Leaves have normal colour. Does anyone know what could happened with them?


Posted by: Ivica Bicanic (1 point) Ivica Bicanic
Posted: June 23, 2016




Answers

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I think it is fruit fly damage. The female fruit flies pierce the fruit to lay egg under skin. Generally they lay 3 to 8 eggs. After one or two days the hatched maggots starts feeding on internal content of fruits causing sunken, discoloured patches, distortions and open cracks. This damage also act as entry site for fungal and bacterial pathogens which causes fruit rot. After few days the maggots fall out of the fruit and pupate in soil.

MANAGEMENT

1. Destroy the infected fruits.
2. Also harvest fruits early to reduce flies damage .
3. Use traps to monitor fruit flies. Traps can be purchased in the market or one can prepare themselves. Take plastic container with lids (one quarts yogurt container is fine). Drill holes (10 to 16 holes) that are 3/16-inch in diameter around the upper side of the container. Add 1 to 2 inch of vinegar and 4 -5 drops of unscented liquid dishwashing soap into the container. Place the container in shade near plants before fruits ripening and check the traps frequently for flies. Change the vinegar every week.
4. Spraying protein bait under leaf surface attract flies to single spot which make easier to kill them.
5. Also spray neem oil frequently to repel fruit flies.
5. If infestation is severe you can spray suitable insecticide.



Posted by: Dr. Ravishankar Narayana (11 points) Dr. Ravishankar Narayana
Posted: June 24, 2016


Ivica Bicanic commented,
Thank you for answer. I'm almost sure that it wasn't insects who caused damage. I didn't saw any insects in my greenhouse, I've already protected plants against them. There are many fruits with normal shape and without any damage.
over 4 years ago.

Dr. Ravishankar Narayana commented,
Thanks for your reply. Is it possible to cut open the infected fruit (near sunken side) and upload images. It will help us to diagnose further.
over 4 years ago.



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points
There it is. I hope that will help. It's first time I'm growing watermelons some advice is helpfull. Thank you.


Posted by: Ivica Bicanic (1 point) Ivica Bicanic
Posted: June 24, 2016




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points
My initial impression on seeing the first two photos was that it might be sunburn/sunscald. The upper side of the fruit was yellowed and the fruits do not have much shading. The scalded spots usually turn brown/black due to the growth of saprophytic fungi. However, the cut fruit photo looks like poor pollination on one side causing the fruit to develop unevenly.


Posted by: Charlie B. (2 points) Charlie B.
Posted: June 24, 2016


Ivica Bicanic commented,
Thanks for answer. It's possible that pollination was poor, it isn't many bees in Norway this spring/summer, so I've used hand pollination.
over 4 years ago.



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