by Nathan Jackson

What’s Small, Squishy, and Hated by Every Rose Grower?

Aphids and they can be found nearly anywhere roses are grown. It seems that almost everybody can recognize an aphid when they see it. Some aphids are monophagous, meaning they only feed on 1 type of plant, however most will settle for about any plant in your garden.

About 1/8” in size, aphids can be green, purple, yellow, brown, or just about any other color. They are generally pear shaped, and most have 2 “tail pipes”, called cornicles, sticking out their abdomen. These soft bodied pests suck the juices out of plants using mouthparts called stylets. As they feed, the cornicles secrete a sticky substance called honeydew which should be hosed off or wiped off with soap and water. If honeydew is left on the plant, it can cause a black sooty mold that can eventually kill the plants.

Many species of ants love to feed on the honeydew, and will “herd” aphid colonies and take them from plant to plant to feed. The ants will defend the aphids from attack, so if ants are present it can help to spread some Diatomaceous Earth around the base of plants to help keep them under control. Aphids can also be a vector for viruses which can wipe out entire crops. Infected plants need to be pulled and disposed of immediately.

During early Spring and Summer only female aphids are present. They do not need a male to reproduce, and give birth to live aphids which are identical (only smaller) to the mother. They live up to 40 days and have multiple generations per year. When the days shorten and the temperature starts to drop in the Fall, aphids start to produce both males and females. The males and females mate, and the females lay eggs which will winter over. The following Spring when the weather warms, the eggs hatch, and the cycle begins again. Occasionally, especially if there are high populations of aphids and little food, females will lay eggs that hatch into winged aphids which will fly off to find other food sources.

Ladybugs (Hippodamia convergens) are probably the most common predator used to control aphids. Although they have a reputation for flying away to your neighbor’s yard, they are still an inexpensive control. Small handfuls can be applied every few days to ensure you have continuous control. One ladybug can eat over 5,000 aphids during its lifetime and with luck, ladybugs will reproduce in your yard. Ladybug larvae are voracious feeders, and are great predators to have in your garden. General feeding predators like Ladybugs, Green Lacewings, and Pirate Bugs are good at controlling not only aphids, but other small, soft bodied insect pests like mites, thrips, and whiteflies.

Aphid Predators (Aphidoletes aphidimyza) are used in greenhouses for long term control. They work so well that after 1 or 2 releases in the spring aphids can be hard to find by the middle of Summer. Aphid Predator adults are frail looking winged midges. They fly around plants and lay up to 250 eggs near aphid colonies. The eggs hatch, and the Aphid Predator larvae begin to search for aphids. The larvae bite the knee joint of the aphid and inject a paralyzing toxin. After the aphid stops struggling, the predator bites into the thorax and sucks out the body contents. After eating about 10 aphids and reaching full size, larvae drop to the soil and pupate into an adult. The entire life cycle takes about 3 weeks at 68 degrees.

Aphid Parasites (Aphidius matricariae) are good at searching out scattered aphid populations. They are not an ideal single control, but when used along with other predators they can help to find the aphids others may miss. They also reproduce very well in greenhouses and back yard gardens. Aphid Parasites work by laying one of their eggs inside an aphid and the resulting larvae consume the aphid from the inside. The parasite then spins a cocoon inside the dead aphid, and pupates. The dead, parasitized aphid swells and stiffens into a leathery, brown, mummy-like wrapping. These are referred to as aphid "mummies", and are a sure sign the parasites are working. Adult Aphid Parasites chew a small hole in the mummy and flies off to find more aphids. Over her lifetime a single female typically attacks 200-300 aphids. The entire life cycle takes about 3 weeks.

There are over 4,000 species of aphids, they have existed for 280 million years, and they aren’t going away anytime soon. Soapy sprays can be used initially, followed up with predator releases for best results.

Treat them early and don’t think one aphid won’t turn into thousands...if left alone it will.

Nathan Jackson is the owner of Nature’s Control and Ladybug Indoor Gardens. You can send your specific bug questions to This e-mail address is being protected from spam bots, you need JavaScript enabled to view it For more information, to request a catalog, or to find a local distributor, check out www.naturescontrol.com or call (541) 245-6033.