Plants injured by aphid feeding will have leaves that appear curled, distorted and discolored. Small to medium sized aphid populations are easily overlooked. In some cases the first sign of infestation is distortion as a result of one of the mosaic viruses the aphids transmit. Other common signs are leaves that appear wet but are actually covered with honey dew and the presence of a black sooty fungus growing on the honey due. Aphid populations can increase very quickly and it is not uncommon under the right conditions to find hundreds of aphids per plant.
Aphid outbreaks are most frequent in hot dry weather.
While heavy rains will often reduce the aphid population below the economic threshold. When pesticides are applied care should be taken to select pesticides that are not damaging to natural enemies of aphids. Because aphids reproductive rate is greater than their natural enemies, incorrect pesticide use may contribute to aphid outbreaks by removing the natural enemies. Fields of peppers and Cole crops should be scouted for the green peach aphid throughout the year especially during hot dry weather and 5 days to a week after a pesticide application.