What could be a typical sign of bacterial plant pathogens?

The presence of ooze is a hallmark sign of bacterial plant pathogens. This ooze is often a result of the bacteria producing a viscid substance as they infect plant tissues, particularly during periods of warm, wet weather. The ooze can typically be observed from infected plants, flowing from lesions or wounds, and may be seen pooling on the leaves or stems. It contains bacteria and can facilitate their spread to other plants, contributing to the disease's progression.

In contrast, other options may be associated with different types of pathogens. For instance, necrosis of leaves can occur due to various biotic (bacterial, fungal) or abiotic (nutrient deficiency, environmental stress) factors. Wilting without yellowing is commonly seen in cases of root damage or vascular problems, not specifically linked to bacterial infections. Spore production is a characteristic associated with fungal pathogens rather than bacterial infections. Thus, ooze is distinctly representative of bacterial activity in plants.