Diseases Affecting Tomato Crops During The Fruiting Stage

During the fruiting stage, your tomato plants enter the crucial period of growth and development, promising a rewarding harvest. However, this crucial phase is also susceptible to various diseases that can hinder the health and productivity of your tomato crops. In this article, we will explore some common diseases that can affect your tomato plants during the fruiting stage and provide effective treatments to ensure a healthy and successful tomato crop. 

Common diseases that could affect your tomato crops during fruiting stage include: 

Fusarium Wilt

Causal Organism: Fusarium oxysporum f.sp. lycopersici  

Symptoms

• Yellowing of older leaves, wilting, browning and defoliation.
• Dark brown streaks of vascular tissues can be observed when cutting an infected stem at the base.
• This disease stunts growth, hampers fruit development and often leads to the premature death of the plants.

Control Measures

• Uproot the infected wilt plants from the tomato field to prevent the further spread of the disease.
• Avoid water stagnation and limit the use of nitrogenous fertilizers.
• Use Multiplex Nisagra Bio Fungicide (Trichoderma viride 5% L.F) at the rate of 2 kg per acre.
• Drench the affected area with Spectrum Fungicide (Azoxystrobin 11% + Tebuconazole 18.3 % SC) at the rate of 300 ml per acre. (Or)
• Use Infinito Fungicide (Fluopicolide 5.56% + Propamocarb hydrochloride 55.6% SC) at the rate of 2 ml per liter of water.

Early Blight

Causal Organism: Alternaria solani 

Symptoms

• It appears as small black lesions on the older leaves, which gradually turn yellow and form leaf spots from the bottom of the leaves.
• These spots may enlarge and exhibit concentric rings in a bull eye pattern, accompanied by a yellow halo in both foliage and fruits.

Control Measures

• Use Revus Fungicide (Mandipropamid 23.4% SC) at the rate of 1.6 ml per liter of water. (Or)
• Apply Antracol Fungicide (Propineb 70% WP) at the rate of 2 gm per liter of water. (Or)
• Use Curzate Fungicide (Cymoxanil 8% + Mancozeb 64% WP) at the rate of 2 gm per liter of water.

Late Blight

Causal Organism: Phytopthora infestans 

Symptoms

• It is characterized by small water-soaked regions, which quickly develop into purple-brown and oily blotches.
• Greyish white mycelial growth can be observed on the undersides of the infected leaves, surrounding the blotches.
• It spreads rapidly, affecting petioles, young stems and even fruits, resulting in significant losses in production.

Control Measures

• Use Acrobat Complete Fungicide (Metiram 44% + Dimethomorph 9% WG) at the rate of 2 gm per liter of water. (Or)
• Use Sectin Fungicide (Fenamidone 10% and Mancozeb 50% WG) at the rate of 2 gm per liter of water. (Or)
• Use Zampro (Ametoctradin 27% + Dimethomorph 20.27%) at the rate of 2 gm per liter of water.

Bacterial Leaf Spot

Causal Organism: Xanthomonas campestris pv. vesicatoria  

Symptoms

• It is characterized by the appearance of black or dark brown leaf spots with yellow halo on the fruits, which eventually turn from yellow or light green.
• Larger leaf blotches, particularly on the leaf margins can be seen.
• This disease can also affect twigs and green fruits.

Control Measures

• Use Shamrock Overseas Borogold (Colloidal Nano Silver Technology) at the rate of 1.5 to 2 gm per liter of water. (Or)
• Use Conika Fungicide (Kasugamycin 5% + Copper Oxychloride 45% WP) at the rate of 2 gm per liter of water. (Or)
• Use Amistar Top Fungicide (Azoxystrobin 18.2% + Difenoconazole 11.4% SC) at the rate of 1.2 to 1.5 ml per liter of water.

Tomato Spotted Wilt Disease

Causal Organism: Tomato spotted wilt virus 

Vector: Thrips (Thrips tabaci, Frankliniella  schultzii, Scirtothrips dorsali) 

Symptoms

• Bronzing of the upper surface of the younger leaves, which finally turns into necrotic spots.
• Downward cupping of the leaves and tip of the shoots show dieback symptoms.
• Spots with concentric circles or circular markings can be seen on fruits.
• On ripe fruit, chlorotic spots and blotches appear in alternate bands of red and yellow, often with concentric rings.

Control Measures

There is no treatment for the plants infected with this virus. To prevent the spread of TSWV, it is crucial to monitor for thrips and tomato spotted wilt symptoms from the seedling stage and promptly remove and destroy infected plants. Additionally, the removal of weeds in the tomato field is recommended as they act as alternate hosts for thrips.  

Bacterial Wilt

Causal Organism: Ralstonia solanacearum 

Symptoms

• Within 2 to 3 days, terminal leaves start wilting, and later the entire plant may permanently wilt.
• Vascular bundles may also exhibit brown discoloration, and bacterial ooze comes out when the freshly cut stem is placed in water.

Control Measures

Control of Bacterial Wilt is quite difficult. One way to reduce the infection is to remove the infected plants by burning or burying. To prevent the further spread of the disease, increase calcium availability by liming or adding bleaching powder (Calcium hypochlorite) and avoid excessive irrigation. 

Powdery Mildew

Causal Organism: Leveillula taurica, Oidiopsis neolycopersici 

Symptoms

• Infected plants exhibit patchy white powdery growth on the lower surface of the older leaves, which can subsequently spread to both leaf surfaces, leading to chlorosis and defoliation.

Control Measures

• Use Luna Experience Fungicide (Fluopyram 17.7% + Tebuconazole 17.7% SC) at the rate of 1 ml per liter of water. (Or)
• Use Nissodium Fungicide (Cyflufenamid 5% EW) at the rate of 0.6 ml per liter. (Or)
• Use Nativo Fungicide (Tebuconazole 50% + Trifloxystrobin 25% WG) at the rate of 0.5 gm per liter of water.

Note: Taking proactive measures to control diseases at the fruiting stage is crucial for the successful growth of your tomato plants. Regularly monitor your plants for signs of disease infection and promptly intervene with recommended fungicides. Remember to follow instructions on the product labels and take appropriate safety precautions when using any fungicides. 

Conclusion

To prevent and control these diseases, it is vital to practice proper sanitation, implement crop rotation and consider disease resistant tomato varieties. Chemical treatments can be employed alongside these preventive measures for disease management. With proper care and attention, your tomato plants will flourish and reward you with a plentiful harvest.