The amount of time between thrips feeding and the appearance of symptoms varies. It is host and temperature dependent. Symptom expression may occur in less than one week in 'Calypso' petunia and within five days in gloxinia. A virus infection also can be latent and symptoms may not appear for months. Thrips life cycle.
Symptoms often resemble fungal or bacterial diseases or nutrient deficiencies.
Plants may not show any symptoms at all. Such plants include the petunia cultivar 'Calypso' and gloxinias. Both plants are extremely susceptible to both viruses and will show symptoms within a week after infection. Non-sticky blue or yellow cards placed near indicator plants can attract thrips and increase the likelihood that plants will become infested. Management Viruses cannot be controlled with pesticides.