Closely related, aphids, scales, mealybugs and whiteflies are all sap-sucking insects. They also produce honeydew, a sweet, sticky liquid that oozes from them as they suck plant juices from various plant parts. One problem is that wherever the sugary honeydew solution lands (leaves, fruit or stems), sooty mould can take hold. This ashen-looking fungus does not infect plants but can interfere with photosynthesis, affecting plant growth and causing leaf drop and unsightly, sooty-coated foliage and fruit.
Aphids are especially common on roses but can also affect plants in the vegie garden. They particularly like beans, peas, melons, cucumbers, pumpkins, squash, tomatoes, potatoes and cabbages. Apart from sucking, they can transmit diseases to many edible crops when they move from plant to plant. Their actions can result in young foliage looking…