Neem oil + Bacillus thuringiensis - bad reaction!

duartix

2 days ago I've prepared a mix of these two insecticides since one of the packages said these are a lot more effective when mixed together.

The recomended dose of Neem was 1 to 1,5 cc/l.
The recomended dose of the Bacillus thuringiensis was 1cc/l.

Well, I've got so puzzled by the neem consistency that I forgot my sprayer capacity was 0,5l, so to put it shortly I've at least doubled the dose.

Another thing I didn't followed was the PH of the water I used in the dilution. It said something about 6 to 6,5 and the water here in Lisbon is 7,0.

Another thing that I'm not sure is wether the fact of using them mixed, implies that the dose should be halved (the instructions say nothing about this).

4/20 trees are showing varied levels of black spots on foliage.

Trees affected:
Chinese Elm.
Ficus Carica.
Pyracanthea.
Rosmarinus prostatus.

Trees not affected:
Connifers.
Olive.
Robinia.
Sageretia.
Serissa.
Ficus.

Anything I can do?

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Ashbarns9999

We must live in fairly similar climates but the most radical spray in use here would be pyrethrum. If you could consider that ulmus parvifolia can lose it's foliage through various sprays i myself go for caution. I just worry about how much damage these things cause to us and our trees. Please think of your environment and your personal health.
My best wishes for you and your family. Ash

__________________
Better to procrastinate than lose sight of the objective by rash deeds.

http://www.bonsaivault.com

duartix

Well, I'm sorry Ash, I believe in IPM, and from what I've gathered, probably both Neem and BT are less toxic than pyrethrum.

Let me tell you something, I've got a cochonilha infestation for about 3 months now and I have refused to used any chemicals until now (if you consider BT or Neem chemicals, which I don't).
I have had a professional nurserie (the biggest in Portugal) advising me to take my trees there so they can give it a Malathion shower (it's what they do with their own material, you know?).

I've seen people in that nursery forum saying they use fungicides like Previcur, Alliete, Benomil or even Baycor S as a preventive measure, and I've been bashed for calling them redneck farmers (well not really with these words) as far as ecology was concearned.

It's because I think about the environment and my family's personal health, that I hold the infestation for so long, refused to take my trees to this nursery, and performed a much much lower toxicity treatment myself.

Perhaps you would think of me diferently...

Ralph

I don't know how effective your spray will be for what you are trying to do. If you are suffering from fungal problems spraying an insecticide based formula may not be your best bet. How about a picture or two of the plants affected?
This link has some great info on Black spot, if that is indeed what you have.
http://www.dallasbonsai.com/bonsai_...hineseElm2.html

Concetrated Neem can impede leaf transpiration, so be careful with how much you use, maybe someone with direct experience using this product on bonsai can give you additional info on how strong a mix you can go with.

Step one, get a sure diagnosis of an insect or fungal related problem from a pro, and maybe more than one source.
Step two treat for that particular problem.
Step three, address environmental issues that may have led to the problem (ie: watering process, air flow, light, soil drainage....)

__________________
Emerging from winter slumber
Bonsai trees burst buds anew
Spring is upon us!


-Paul S.

duartix

Right now, I can't give you a picture of the trees affected, but I can give you a picture of what exactly was infesting them, cochonilha as I said before.

I know nothing on how the trees could possibly be affected by either BT or Neem in the way they were, but yours is a reasonable explanation Ralph, perhaps the concentration was too heavy and the leaves are drying out, I shall give the trees another shower tonight,...

Thank you.

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duartix

First 2 are of the Ficus Carica.
Third one is of a chinese elm.

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