Diseased leaves on melons

Last post 05-06-2011 8:00 PM by Marky L. 2 replies.

• 20/05/2011 07:54 PM
  Marky L Location: Hampshire Joined on: 20 May 2011 Posts: 2	Reply | Contact My first post! We have some melon plants growing in our greenhouse and, on two of the plants, the leaves have developed what looks like leaf spot. We have removed the worst of the affected leaves. Is there a recommended product for spraying them? Failing that, should we separate the affected plants and take them out of the greenhouse? Looking forward to your advice.

• 30/05/2011 11:14 PM

  In reply to

  hydropiper Location: Cardiff Joined on: 23 Jun 2009 Posts: 162

  Reply | Contact You say you have "leaf spot". Are the spots yellow, black or white? Melons like marrows can have quite bumpy leaves sometimes, but this is normal. However, you may have mosaic virus, which affects many members of the cucumber family such as melons. This is usually indicated by the appearance of irregular yellow leaf spots. There is no treatment for this, other than to destroy and dispose of the plants. Another possibility is redspider mite (yellow/brown mottling and fine webs beneath the leaf) or powdery mildew (white spots which eventually join up to cover the whole leaf). These can occur if the air inside the greenhouse is too dry and ventilation is inadequate. To control both these problems keep plants well watered throughout the growing season, especially during hot dry spells and on hot sunny days soak the path and ground around the plants with water. This water will then evapourate raising the humidity levels inside the glasshouse which will discourage the spider mite. Always water in the morning before the sun is at it's strongest, so that the plant has a chance to take up the water before it is evaporated by the midday sun. Good ventilation is also key, so make sure that you open the vents, doors and windows during the day, but remember to close them at night, when temps will drop off again.    Chris

• 05/06/2011 08:00 PM	In reply to
  Marky L Location: Hampshire Joined on: 20 May 2011 Posts: 2	Reply | Contact Thanks Chris. The leaves appeared to have had rust colour spots on them. We removed the affected leaves and the problem appears to have gone away. However a couple of the plants now have wilt! We had been following the watering and ventilation regime you suggested. We have a fan in the greenhouse running 24/7.