In these circumstances, ants may supplement their honeydew intake by preying on the aphids once the aphid populations have reached certain densities.

Because the transmission is non-persistent, pesticides do not provide effective control of the virus unless used as a preventative measure to reduce aphid populations.

In the last three decades, this insect has spread throughout the United States and Canada, and has been a prominent factor in controlling aphid populations.

Both are relatively nontoxic and will not harm beneficial lady beetles (or the larvae) that feed on scale crawlers and wipe out aphid populations.

Several generations of an aphid population can exist over the lifespan of a single leaf.

However if the fall or spring is cool and wet the aphid population decreases and virus spread as decreases.

Larvae can consume aphids much larger than themselves and may kill many more aphids than they eat when aphid populations are high.

By mid summer, the number of predators and parasites has built up and aphid populations cease to expand.

Various factors influence aphid populations.

Therefore, PLRV can be controlled effectively by reducing aphid populations.