Neem oil and sanseverias

18 years ago

I have most of my sans on a table with my haworthias, where they only get an hour or two of morning sun, and that, mainly dappled. Several evenings ago, I made the mistake of spraying everything on the table lightly with a 1/2 & 1/2 mixture of neem oil and water to discourage ants. Early the next morning, the plants with smooth leaves still looked shiny, so I carefully wiped off any excess oil to make sure the sun would not cause damage, and everything looked better than ever. The following day, the haworthias still looked better than ever, but the sans with shiny flat leaves had developed sunken and rotten-looking light brown areas here and there on many of their leaves. I think it can only be that even the thin film of residual oil had caused sunburn. (Yet, strangely, this did not happen in the case of the haworthias.) Fortunately, the sans all had enough good leaves left so that I could remove most of the affected ones, but they won't look good for a while. I am making this embarrassing incident public in the hopes of saving someone else a similar experience.

Featured Answer

gulfcoastsans

18 years ago

What a tough way to learn of the problems with residul oil. For several years I've been using Cygon 2-E on my Sans for pest control and while there has been no problem, just this past Thursday (8/25) when Juan Chahinian was visiting, he told me to make sure my dilution rate was low since the oils in Cygon can cause a similar problem. Apparently my 1/4 tsp. of Cygon to 32 oz. water is okay since I've yet to see the conditions that occured on your plants using the Neem Oil. You might try using a type of ant bait stake in and around your plants. I tried that this year and have had less of a problem than in years past.

Comments (8)

dufflebag2002
18 years ago
I am also glad that you brought up that point/problem,
I love Neem oil for white fly and meelies, and that is the only thing I use it for. It's is so important to know what can be used for what species. Saffer's is not good on Echinopisis. I have been using a little vinagar and a lot of water to get off the water spots, and then milk to clean the leaves. We cant buy Cygon 2-E in California at this time.
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biwako_of_abi
Original Author
18 years ago
I am grateful that nothing important actually died, and the sans are putting out new leaves, so I can gradually cut off the bad ones. I guess I will have to use some sort of ant baits, as Gulfcoast Sans suggested. By the way, the neem oil also damaged some of my faucarias and a few cacti.
dufflebag2002
18 years ago
That is correct. We use it for flying insects, I used it on my Hoya, it must not be used on anything that has a bloom (powder on the leaves) I only use 1-2 tbs per gal of water. Follow the directions exactly. Norma
Hap_E
18 years ago
Half and half is very strong solution of Neem. I use a single teaspoon to 32 oz of water with a few drops of soap as an emmulsifier with very good results and no burning. However I only use 100% Neem, not one of the brands that cut it with other things... (why do some brands use paint thinner?)
jon_d
18 years ago
Cygon is not a product I would use. I tossed my last bottle, which was unused (it went to the toxic waste center). It is one of the most toxic insecticides around, and hasn't been available in California for about a dozen years. Check out its LD50 number before you continue use to see if you still feel comfortable in using it. I would definitely use a full face mask and spray on windless days outdoors.

Jon
minibot
18 years ago
I used neem oil 1 tsp to one quart and warm water and drops of dishsoap on my easter cactus and it developed ugly, ugly warts like the plant was allergic. It never got rid of the bumps. I was so livid! New growth is normal of course. So, if you like welts on your plants use it ;-) It makes an interesting, alien look for the plant! I'll think twice before using it on any succulent type plants. My orchids are okay with it though.

minibot
rhizo_1 (North AL) zone 7
18 years ago
Cygon has been yanked from the market (for very obvious reasons) and should not be found in any stores that market to residential consumers. The withdrawal is voluntary at this point, I think, though it will certainly be unavailable in the very near future. Thank goodness. The thought of good people using these products on house plants is frightening!