Identification: Thrips are tiny, slender, yellowish to blackish insects with fringed wings. They are typically found on leaves and between flower petals. The adults are very difficult to see without a magnifying lens.
Damage: Both adults and nymphs (immature stage) feed by scraping surface cells to suck plant sap. Leaves fed by thrips will often take on a silvery or speckled appearance. As thrips are very tiny they are not visible to the naked eye. For this reason, it’s very important to monitor the plant closely - if there are silvery spots on leaves, it is probably a thrips damage and it can be managed when detected at an early stage.
Thrips damage on basil leaves
Control:
Mechanical- In the early stages, take off damaged leaves with silvery spots to avoid nymphs growing up and making a whole new colony.
Biological control- Natural enemy (Amblyseius swirskii, Amblyseius cucumeris, Hypoaspis miles). Biological control should be used continuously to keep down the number of pests.
Neem oil - It inhibits insect nutrition and fertility, therefore life cycle will be disturbed. Follow package instructions for diluting the oil in water and spray the affected areas, repeat if necessary. Although neem oil is of natural origin, wait a few days after spraying before eating your plants.
Discarding the plants- With a heavy infestation, it may be necessary to discard the plant, disinfecting the garden. Wait for 1-2 weeks before plugging new soils in to avoid continuing pests life cycle.
