Scientific Name

Speck: Pseudomonas syringae pv. tomato
Spot: Xanthomonas campestris

Overall Plant Symptoms

Plant stunting and reduced yields if young plants are severely infected.

Leaf Symptoms

Round, small black specks, some with yellow halos. Specks coalesce, black ragged leaf margins.

Stem Symptoms

Similar to leaf symptoms.

Root and Fruit Symptoms

Fruit: superficial black raised specks with yellowish ring or halo. Later scabby, with darker halos. Hard to peel. No root symptoms.

Disease Source

Infected seed, transplants, tomato crop residue, several weed hosts. Commonly found at low levels statewide.

Source Peristence

Speck: survives on other plants but disease inoculum greatest after tomato crop. Time reduces inoculum.

Favoring Conditions

Both: Splashing rain, sprinklers.
Speck: favored by cool conditions, <70^o.
Spot: favored by warmer conditions, 75-85^o.

Critical Crop Time

Emergence to five leaf, yield loss. Fruit is damaged during green stages.

Controls/Management

Speck: Resistant varieties are specific to only P.s. pv. tomato. Both: Copper and Maneb or Mancozeb. Protectant only, full plant coverage.

Additional Notes

UC Pathology Lab has methods to differentiate spot from speck.