Although appropriate insecticides a

Although appropriate insecticides are usually very
effective in killing aphids breeding on plants and
can provide good control of viruses transmitted in
a persistent manner, they are usually ineffective in
preventing the spread of non-persistent viruses.
This is because of the extremely short feeding times
needed to transmit non-persistent viruses from
plant to plant. As aphids move through a crop and
briefly probe, by the time an aphid receives a lethal
dose of insecticide it will often be long gone and the
damage already done. Some insecticides agitate
aphids and encourage greater movement and
feeding, resulting in increased rates of virus spread