Tomatoes are famous for their succulent, juicy fruits rich in great taste and nutrients including Vitamin C, Potassium, Folate and Vitamin K. No wonder everyone at the market would always carry some home- and pay really well for them. The market for tomatoes has in the last year stabilized a little bit- with increased consumption; though good market intel is still useful to keep you safe from glut situations where you have to sell your tomatoes at throw away prices or sometimes even don’t get a market for your precious produce.
That said- Tomato production in tropical countries like Kenya does not come without challenges. The tomato is arguably one the most delicate crops to produce in Kenya. High prevalence of diseases and pest attack on the crop has often caused farmers to spray a lot of chemical pesticides and fungicides on their crop- which eventually finds itself in the produce, affect non-target organisms, and cause pesticide poisoning to users. One of the most common tomato diseases is blight.
High prevalence of diseases and pest attack on the crop has often caused farmers to spray a lot of chemical pesticides and fungicides on their crop- which eventually finds itself in the produce, affect non-target organisms, and cause pesticide poisoning to users.
There are two types of tomato blight known: early tomato blight and the late tomato blight.
a. Early blight
Early tomato blight is caused by a fungus called Alternaria solani. Early blight can affect the crop at all stages of growth and mostly thrives in humid and warm weather conditions.
Some of the major symptoms of the disease include: damping-off, formation of stem cankers, crown rot, leaf blight and fruit rot
b. Late blight
Tomato late blight is caused by a fungi-like pathogen known as Phytophthora infestans. Different from the early blight pathogen, Phytophthora infestans thrives in cool and wet conditions.
The two most recognizable symptoms of attack include: leaf lesions (they start as pale or olive-green areas and rapidly change to brown-black. The lesions appear oily and may produce whitish grey, fuzzy spores) The fruit shows few symptoms initially, but soon develops ringed, golden to chocolate brown lesions or spots that may appear sunken.
Farming Practices To Reduce/Avoid Attack
- Do not work in your garden during wet conditions. Working in wet conditions is most likely going to spread the spores in the garden/field.
- Remove, burry or burn all dead or infected plant parts- this prevents the spread of spores to healthy plants.
- Allow adequate spacing for your tomato plants so that there is optimum air circulation and keep the leaves and stems dry. This prevents growth and multiplication of spores.
- Water the plants early in the day to encourage rapid drying of the foliage before cooler night time temperatures arrive – This especially controls the late blight as it does not allow the pathogen to have its two most convenient conditions.
- Control harmful insects in your garden to minimize plant injury and the spread of spores caused by their feeding.
Treatment/Management in Already Infected Fields/Gardens
I. Compost TeaCompost tea can effectively control both early and late blight diseases in tomatoes, it also enhances soil nutrients and soil health as well as necessary plant nutrients- (healthy robust plants can resist/withstand pest and diseases attack). A recent study by the Tasmanian Institute of Agriculture has confirmed the science behind this old practice. According to the study- bacteria found naturally in compost acts to protect plants from pathogens such as other bacteria, fungus etc. by producing biofilm which is a natural shield against pathogens. How do you make a great compost tea?Compost tea is made by mixing about one part of well-aged compost that is at least 4 months old and 5 to 8 parts of water. The mixture is placed in a covered container and allowed to sleep outside at temperatures between 15.5 degrees Celsius and 21 degrees Celsius for 5 days. The tea must be stirred daily during the 5 days. On the fifth day, the material is poured through a sieve or gunny bag/cloth and the strained tea applied to plants as a foliar spray. Compost tea should not be sprayed on the fruit if you plan to harvest in the following 2 to 3 weeks. Make sure the materials are well composted so as not to introduce contamination of dangerous micro-organisms such as E-Coli. Use of baking powder/baking sodaYour ordinary baking powder has fungicidal properties that can fight both early and late tomato blight. Make baking soda spray by adding one tablespoon of the powder into every 1 litre of water. Add a few drops of liquid soap or vegetable cooking oil to make the spray stick on the plant leaves/surface for optimum action. Pour the mixture into a spray bottle and shake thoroughly before applying to the entire plant. Baking soda fungicides should be applied out of direct sunlight to avoid burning your plant, and do not make it too strong. Too much baking soda can damage your plants.