TOMATO - BACTERIA

BACTERICAL CANKER

Source: https://gd.eppo.int/taxon/CORBMI/distribution

Source: https://gd.eppo.int/taxon/CORBMI/photos

Control: No direct control measures are available. Phytosanitary measures and the used of certified disease-free      seeds and transplants      are the key to the control of the disease:

• obtain      seeds from healthy stands only; seeds should be thoroughly fermented,
• disinfect      seeds with calcium hypochlorite or hydrochloric acid,
• sterilization      of substrates, steam sterilization of      pots and stakes,
• crop rotation,
• avoid      overhead irrigation,
• removal and destruction of      infected plants,
• avoid touching the plants when they are wet (transplanting, cultivation, pruning, harvest),
• if bacterial canker identified, incorporate plant debris into soil by ploughing to speed up decomposition.

BACTERIAL SPECK AND BACTERIAL SPOT

Pathogens: Pseudomonas syringae pv. tomato and Xanthomonas campestris pv. vesicatoria
Host range: Tomato and other solanaceous species.
Importance: Both diseases are present worldwide.
Symptoms: Both pathogens cause small (1-3 mm), dark necrotic spots on leaves usually surrounded by a yellow halo, and irregular dark spots on stems and petioles. Spots may merge to form large necrotic areas. Leaf edges may get torn and the entire leaf may eventually die. According to the leaf symptoms only, it is not possible to tell which bacterium is responsible the disease in a particular case. Both bacteria can cause spots on fruits. Spots caused by Pseudomonas syringae pv. tomato are small (1-2 mm), raised, dark brown to black, sometimes with a dark green halo as opposed to those caused by X. campestris, which are larger, brown, scablike, with raised margins but a sunken centre.
Leaf symptoms may be confused with those of the fungal disease Septoria leaf spot. Bacteria      infect younger leaves whereas Septoria prefers older ones. In bacterial spots, there are no pycnidia (black dots) present.

Source: https://gd.eppo.int/taxon/PSDMTM/photos

Disease cycle: Both bacteria are able to survive on seeds and plant debris in the soil up to several months. High humidity is essential for the spread of the bacteria. Bacteria are dispersed by wind-driven rain droplets, aerosols and touching plants during transplanting, cultivation, pruning, and harvest. They are only able to infest plants through injuries. Pseudomonas syringae pv. tomato lower temperatures (18-24 °C), whereas X. campestris needs warmer conditions (24-30 °C).

Treatment: No effective control measures are available. Phytosanitary measures (healthy seeds and plants) are the key to the control of the disease.

• obtain seeds from healthy stands only; seeds should be thoroughly fermented,
• disinfect seeds with calcium hypochlorite or hydrochloric acid,
• sterilization of substrates, steam sterilization of pots and stakes,
• crop rotation,
• avoid overhead irrigation,
• removal and destruction of infected plants,
• avoid touching the plants when they are wet (transplanting, cultivation, pruning, harvest),
• if the disease is identified, incorporate plant debris into soil by ploughing to speed up decomposition,
• copper fungicides may help to maintain plant health.

BACTERIAL WILT

Pathogens: Rastolnia solanacearum
Host range: Ralstonia solanacearum survives on all Solanaceae (cultivated species, weeds and ornamentals); however, in many cases it persists in a latent form, without causing symptoms. It also infects several leguminous species and weeds.
Importance: The pathogen is widespread in the eastern Mediterranean basin and the Black Sea area, but is also present in Central / Eastern Europe countries. In hot, dry summers it often infects plants without causing symptoms. As Ralstonia solanacearum is a quarantine pest, its presence may result in the destruction of symptomless crop batches. 

Distribution:

Source: https://gd.eppo.int/taxon/RALSSL/distribution

https://gd.eppo.int/taxon/RALSSL/photos