Aphids Control

Muniz

-Reproduction from another thread post by myself -

Dear Colleagues,

I am posting it, just to share with you a well succeed procedure. Recently, three weeks ago, I identified parasites (aphids) in a small lot of my bonsai collection (12 of 115), in a heavy infestation.

As a researcher, I begun to search in the appropriated specialised literature (and looking through the window my hungry guests eating my trees). Obviously I found two main ways to attack this parasite, use a hazardous organophosphate, for exemple Dichlorvos (DDVP), or use something else less toxic. I found a great amount of literature based on alternative treatment with natural substances (milk, floor, garlic oil, ...). One treatment, the use of mineral oil (a derivative of petroleum), that I discovered latter, was used in plants when organophosphates was not synthesised (DDT was mainly developed for the head of the soldiers against lice in world war), is very studied, with many scientific articles, many of them here in Brazilian plants.

As a summary of all articles that I studied, I decided to test 3 kinds of procedures:
(All of them applied as a spray on leaf, taking a caution with the soil, I used it by night, do not use in full sun because it will burn the leaf)

1 - Mineral oil - 20ml per L of water or 10 ml per L of water.
2 – DDVP – 5 ml per L of water.
3 – A mix: Mineral oil 15ml and DDVP 5ml per L of water.
I tested a variation, first number one and secondly number three.


Results and Discussion

It was very interesting, number one functioning well and produces a good knock-out, killing +- 80% of the parasites population, but the remaining ones can maintain the population, you must use other applications to eradicate the parasite.

As I experienced a heavy infection, the tree was totally occupied, normally (in low infections) only the new buds (in the extremities) is affected by the aphids.

The tree species attacked were: Pyracantha, Hibiscus, Carmona (Fukien tea) and Polyscias. The Hibiscus are very attacked and the last species tree to be free from parasites.

All of the 3 tests kill all of the parasites. I recommend begin with number one and observe, if a considerable amount of parasites survived in the next two days, then use number 1 again, observe, if it persist use number 3. Leave number 2 to a final solution.

The mineral oil is not toxic to the trees, it is decomposed in the soil in a few days. I am now using the mineral oil as a routine in all of my trees, to prevent initial fixation of the parasites (not only aphids, other parasites too). I spray it every week. As a consequence, the leaf became very brilliant, very beautiful (and I hope pest free).

I know, based on the literature and some talks with bonsai masters, that aphids is not the most difficult parasite to control, but is very injuring to our trees. The ideal is the prevention.

In relation to prevention, three months ago, I begun to use Neem oil. I do not have consistent concluding remarks, because this recent aphid experience. I stooped the Neem oil and am using only mineral oil. I am inclined to mix Neem oil and mineral oil and test it.

Other interesting conclusion is that when the tree is infested, it stopped all growth, no buds, no new leaf. As you eradicate the parasite, the plant explode in a cycle of robust development. It serves as a signal to me, it is something like the tree screaming for help.

Notice how it is difficult !, I examine my trees every morning when I water them, but these parasites is very fast and sometimes if you do not use your magnifying lenses, you do not find them, specially if they are located bellow the leaf (hidden).

Well, I hope that it serves to you, if some of you have a guest to dinner like those aphids.

Sincerely yours,

Advertisement