Question
Hi Jim,
I appreciate your volunteering. I too participate in AllExperts in the auto repair category.
We have been growing cymbidiums for many years on the San Francisco Bay Peninsula with good success. Generally however the blooms often are a bit eaten. They are in bud now on the bloom stalks and once again we find lots of ants hiding in the buds. They are being grown in redwood bark chip/orchid planting mixture, in containers outdoors.
We suspect they are in a symbiotic relationship with aphids. So the question is at this point what to do if anything to improve the situation. Any particular chemical to apply and if so to what part of the plant or should we assume there are ant nests in the pot mixture and treat that area instead. I do have some Dursban (which was outlawed in CA a few year ago) that is very effective against ants. But would Malathion against the aphids be a better alternative? Or do nothing?
Thanks for sharing your knowledge.

Answer
Hi Roland,

Hey!  If I have any auto repair questions, I'll look you up on the Experts list.  Fair enough?  (grin)  

Ants normally do not eat flower buds - at least none I know of in the San Jose area.  (grin)  The usual culprit with eaten buds are snails and slugs.  When things get cool and damp, I put out snail bait all over my orchid growing area.  If there are kids or pets around, I would suggest using a product known as Sluggo as it is safe to use around them.  There are several products similar to Sluggo, look for one with the main ingredient being Iron Phosphate.  One thing nice about it is that it also is biodegradeable and can benefit the plants and ground.  

For ants, Dursban is great!  I used up my supply last year and have been using Malathion with good results.  I would not spray the buds or flowers with it but go ahead and spray the plant, pot and the growing area.  If you are leery of spraying into the pots, you can set the pot on the ground and run lots and lots of water through the pot and the ants will come crawling out if there is a nest within.  For aphids, I usually wash them off the buds with a strong water stream then spray for ants afterwards.  

Why are ants attracted to the buds and flowers?  If you look closely at the base of the buds, you may see a tiny drop of a sticky clear liquid, it is sweet like sugar and that is what they are after.  

By the way, this weekend there is an orchid show at Fort Mason in San Francisco.  Lots of orchids on display and there are over 60 vendors selling all kinds of orchids.  If you prefer cymbidiums like I do, look for Royale Orchids, Cal-Orchids and possible New Horizon Orchids.  I will miss it this year because the wife decided she wanted to go to Cambria.  

Hope this has helped.  

Jim Kawasaki
San Jose, Ca.