Home Page

Plant Doctor Archive

Unhealthy tomatoes

What causes my tomato leaves to go brown?


I have a problem with my tomatoes that I am not familiar with. I thought it was blossom end rot, but now I am not sure. The tomatoes are developing black spots (more like holes) when ripening, but not necessarily at the ends. Do you have any ideas on what this is, and what I can do to save the rest of the ripening fruit?


Both of these queries relate to Blight. Late Blight is prevalent in cool, humid conditions. There is no cure but it can be prevented from spreading by picking off infected leaves and fruit as soon as signs appear. Spray plants with Bravo, Greenguard or Tomato Spray. As a preventative, regular spraying at fortnightly intervals with Champion Copper or Copper Oxychloride will reduce the incidence of Blight.

If there is no improvement, removing the infected plants would be the best solution. Be sure to remove and destroy all infected fruit and foliage by putting them in the rubbish bin rather than the compost bin to stop the disease spreading.

Late Blight also affects potatoes.

UnitecAdvice by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor of Resource Management.

Reproduced with permission from NZOOM Home and Garden content,
from the previous website of  TVNZ News

The views expressed here are not necessarily those of the RNZIH

Home | Journal | Newsletter | Conferences
Awards | Join RNZIH | RNZIH Directory | Links

© 2000–2022 Royal New Zealand Institute of Horticulture
Last updated: June 27, 2005