Update on Aphids

We have noticed many small dotted insects on our busy Lizzy plants (impatiens). They are bright yellow or green and are just slightly larger than hundreds and thousands.They stick together in  big groups underneath the flowers on the stalks. We also discovered that they spend lots of time with ants. The ants stick to the aphids  like aphid-vampires and we noticed that they were taking liquid off the ants - just as we had researched. 

The ants are running up and down the stalks. We think they are looking for more aphids. When  you touch the aphids the ants scurry up and down the stalks, too.  We think they could be  trying to protect the ants.


We think the aphids might help the ants - or do the ants help the aphids? This needs further research. 

From monarch.org.nz  we discovered our aphids are called aphis nerii or yellow aphid or milkweed (swan plant) aphid or oleander aphid.  They puncture the stalk of the plant to get food but can leave disease inside the plant. Another question: If the aphids left disease, would it affect other aphids and give them a disease too?


We read that aphids don't like poppies, marigolds, garlic, chives and parsley. We had poppies in our garden until recently. We discovered aphids shortly after the poppies died back. Banana peel may help repel aphids too, we read.  We might start leaving some banana peels in the garden after lunch and see what happens. We will have to tell the principle about this or else we might get into trouble for leaving our food scraps in the gardens and not putting them in  the bin. We wonder if the banana peel could also help fertilise the garden. 


We know that lady birds are helpful, and for our next blog we will have done some research on this. We have seen a few lady birds on our busy Lizzy. They are black and sometimes they have yellow dots. 

We found this lady bird but have not identified what kind it is yet.

A small ant on Kyran's hand

Other questions to research: 

- Are our aphids native to New Zealand? 
- How big can they grow?
- How do you get a male aphid if all adults are female? Do they change from male to female when they are young? Do they mate when they are young and then change into females when they are older? This has us bewildered. 
- Why do they like to sap of the busy Lizzy and not other plants?
- Why do the aphids prefer the busy Lizzy to our swan plant stalks which are still left, leafless, after the caterpillars ate everything?  
- Should we kill the aphids? How would this affect the lady birds? 

Do you notice how the aphids stick together?

Here is some research we did on aphids in general - not just our type of aphid.

Aphids may be green, black, brown, red, pink, or some other colour. They are pear-shaped and usually range in  size from 1/16 to 1/8 inch long* (Need to convert this to metric). Dense colonies of aphids may be found along  the stems or on the underside of a leaf. They are drawn to succulent new growth of plants. Several generations may occur and populations can build up quickly. Aphids stick together in big colonies.
Where there's sugar, there's bound to be ants. 

Some ants are so hungry for the honeydew, they'll actually "milk" the aphids to make them  produce it. Ants feed on the sugary honeydew left behind by aphids. In exchange, the ants protect the aphids from predators and parasites. In fact, honey ants will go to unusual lengths to ensure the health of the aphids in their care.

Can you see the group of aphids  and at least one ant?

Aphids on our busy Lizzy plants

By Lauren and Cameron W.