Aphids or greenfly are small, sap sucking insects that are commonly found on buds and new leaves and stems of roses and other plants.
Identify the problem
Aphids, sometimes referred to as greenfly, are small*, soft insects with pear-shaped bodies and long & thin with sharply bent legs. They can be coloured brown, black, yellow, pink or green.
Typically aphids may cause stunted shoots, distorted leaves, wilting, honeydew and sooty mould.
Aphids survive during the cooler winter months and are usually hidden within leaf/flower buds. They multiply rapidly during warmer months in spring or summer. Aphids can be usually found in clusters on young shoots, flower buds or underneath leaves.
Aphids are sap suckers. Sap is the plant´s food, nutrient and water circulation fluid. When aphids or other sap sucking insects suck sap from a plant, the plant is weakened and there is a risk of the insect infecting the plant with disease.
Aphids feed on a variety of plants but mainly feed on soft leaves and shoots (see also root aphids). Because aphids attack the new buds, the resulting leaves and flowers may never open properly; remaining puckered and curled. Most damaging of all, aphids can transmit serious virus and fungal diseases from one plant to another. A particularly bad aphid infestation often leaves a sticky residue of leaking sap on the plant that will grow a sooty mould, an unattractive fungal growth.
*Most aphid species are 1-3 mm in size. However, there are some larger species such as the Giant Willow Aphid which has been found in many parts of New Zealand in the last decade. This aphid is up to 6 mm.
Prevention is better than cure. Protect your roses, ornamentals and other susceptible plants with a Kiwicare systemic insecticide such as PLANThealth Rose Force, Insect Hit or Spectrum concentrate before they become infested. Spectrum products protect from fungal disease as well as penetrating the plant and making the sap lethal to sap sucking insects. Both kill aphids rapidly without any leaf burn or marking.
To get rid of aphids follow these steps:
- Be on the lookout for aphids in spring. They are usually found in areas of soft plant growth.
- If your plants already have an infestation you can squash them between your fingers but this might be difficult on more than a few buds. Use a Kiwicare systemic insecticide like PLANThealth Rose Force or Insect Hit, or a contact insecticide such as PLANThealth Spectrum concentrate to spray the affected parts of the plants. Make sure the undersides of leaves and inside curled leaves are treated.
- For a great natural and BioGro® certified alternative try Organic Insect Control or Organic Super Spraying Oil . Organic Super Spraying Oil suffocates the aphids on contact but do not spray in the middle of the day as the sun can reflect onto the oil and burn the plant.
- PLANThealth Rose Force, Insect Hit or Spectrum concentrate can also be used to continually protect your plants from aphids once the infestation is under control.
Control Ants and the Sap Sucking Insects they 'Farm' in Trees, Shrubs and Ornamentals
- Apply PLANThealth Insect Hit Granules on the the soil around the roots of affected plants. This kills and prevents ants moving up the plants, and is systemic and taken up by the roots of the plant to control the sap sucking aphids and other insects directly.
Did You Know
Aphids are commonly known as greenfly but not all are green, some are yellow, red, brown or black. Aphids can be oviporous, i.e. they give birth to live young. They can reproduce without eggs and without mating. The sweet secretion aphids produce is food for ants and other insect pests. It will also leave a sticky residue on the plants that promotes growth of moulds including sooty mould.
- Where possible spray the undersides of leaves.
- Carry out a winter spray program on trees and shrubs in dormancy to kill aphid eggs hidden in bark and buds.