The rice root aphid (Rhopalosiphum rufiabdominalis) is a well-known pest in North America that survives outdoors all year round. It can affect plants grown in both soil and hydroponic systems. Unlike other aphids, most of this pest’s life cycle takes place underground, so it may be difficult to identify an infestation. These insects can reproduce year-round indoors. However, they can only live a few days without feeding on a host plant and they give birth to live offspring instead of laying eggs.
Life cycle and appearance of the Rice root aphid
Like most aphids, the rice root aphid appears in both winged and wingless forms. The wingless form is dark olive-green, with a round body 1.4–2.4 mm long. It lives and feeds on the roots of the host plant. The winged form is about 1.8 mm long, darker than the wingless form, with a brown-black head. Aphids in the winged stage will emerge from the soil and fly away to colonize other plants.
Rhopalosiphum rufiabdominalis have entirely asexual reproduction; there are no males, and females are essentially born pregnant with genetically identical offspring. Newborn nymphs reach maturity quickly, in about ten days. Adults can live up to a month, reproducing daily.
Because they suck the plant’s vital sap from the roots, plants infested with rice root aphids will exhibit some or all of the following symptoms:
- Wilting; leaves become discoloured and yellow.
- “Honeydew” deposited on the plant by aphids promotes the growth of mould and fungus.
- Transmission of viral disease between plants.