Tomatoes are sensitive to diseases. Here are the most common diseases attacking tomatoes in Kenya. Once you identify a disease, it is easy to control it. The kind of fungicide you buy will be determined by your trust in a manufacturer and it’s affordability.

Damping off disease

 damping off Symptoms

Stems look shriveled at the bottom, which then wilt and finally die off


Mostly young seedlings in the nursery; can also happen before seeds germinate (pre-emergence)


Cold and wet soils enable the fungi to spread faster


Have well drained soils; avoid use of sprinklers for irrigation; use preventative fungicide between week one and three

 Late blight

Late blight3

late blight 2


Water soaked spots form then enlarge. As the spots enlarge, they tend to leave translucent lesion on the underside of the leaf, which then collapses as the disease progresses.


The fruit. Starts from where the fruit is attached to the stem and quickly to the whole fruit. The stems and leaves are also affected


phytophthora infestans. Spread by spores


Use recommended fungicides

Note: this disease is easily confused with botrytis. Be keen on the damage. For late blight, the lower leaves are affected first and on the fruit, the infection starts where the fruit is attached to the stem


Early blight

early blight1

early blight3

early blight 2


Dark brown spots form and enlarge in a circle. This shape will be seen on the stems and fruits.


The stem, leaves and fruits where the circles are.


Fungus alternaria tomatophilai. The spores are easily spread by wind or water especially overhead irrigation


Use Fungicides

 Powdery mildew

powdery mildew Symptoms

Yellowish spots on the leaves and white powdery deposit of sores on the underside surface of these spots. When severe infection occurs the leaves dry up.


Oidium neolycopersici

Temperatures slightly higher than 20°C and fairly high relative humidity favor infection. Spread through spores


Use furrow rather than overhead irrigation and fungicides

Leaf spot

 leaf spot Symptoms

Circular lesions with a dark margin form on the leaves.

As the disease progresses, leaves fall.


Leaf spot is easily confused with the early blight. However leaf spot will only affect  the leaves


Use recommended fungicides






Commonly known as gray mold, botrytis appears as gray spores on the plant


Stem where cankers (look like hard and dried up parts) appear.

Fruits. Affects from where there are injuries or growth cracks.

Stem end. This is where the fruit is attached to the stalk.


Fungus botrytis cinerea

Although the disease is prevalent in green houses, spores are easily spread by wind or infected plant debris botrytis is triggered by injured or dead tissues which provide nutrients for the fungus.


Avoid injuring plants while working in the farm. (That is why correct crop spacing is key).

Field sanitation

Use fungicides

How to control tomato diseases

It is important to have the right farm practices to avoid/control the above diseases. Here are some good agricultural practices in you tomato farm;

  • Crop rotation. Make sure you do not plant tomatoes on the same field after a season of tomatoes. This “starves” any pathogens in the soil. Any crop in the solanacea family should also not be planted. These crops include; eggplants, capsicums, potato and peppers.
  • Field sanitation. Make sure all old plant debris and infected plants are removed from the tomato field and destroyed.
  • Control a disease once it has been detected. This will ensure that the spread is minimized and losses
  • Always use clean seeds. Avoid buying seedlings from hawkers. Raise your own nursery.
  • Do not use sprinklers for tomatoes
  • Use correct spacing in the field. Check the packaging from the seed sachet.
  • Use goat and chicken manure for tomatoes.

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