QUESTION: I have a large Sharry Baby plant ( oncidium ) , this will be its 4 th year in my care and its putting out 1 spike this year. It has many large pseudobulbs and alot of shaggy ugly leaves. I've cut back some old leaves so young growth can get light and to unclutter the plant . Even if I repot it next year , what do I do with those big old pseudobulbs.The plant is healthy I have it on a south patio under a sun umbrella in San diego, mist it most mornings , water 1 x wk with de-ionized water from aquarium store and use little bit of shultz's orchid food , occasionally bloom booster orchid food .
ANSWER: Jerry, as you may be aware, pseudobulbs serve a couple of functions: storage of valuable nutrients to be used for future growth and "eyes" at its base which give rise to new growth. As the plant grows in the number of pseudobulbs, some of the older pseudobulbs may die. They turn brown and lose substance and contribute nothing to the plant and may be removed-- although they may be attached to healthy paeudobulbs.
Of course, if the plant is larger than you like, you may divide it into two or more plants as long as each has three or four healthy pseudobulbs to support future growth. Best time to do that is when you have new growth. You clearly have taken good care of this plant. Leaves on these heavy duty oncidiums can become unsightly. By removing the worst you will not jeapordize the plant's health. If you decide to remove some of these leafless pseudobulbs, remove three or four interconnected bulbs and pot them up as separate plants. When they start new growth you can give them to friends. The chocolate fragrance of this plant can be a great joy when in flower.
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QUESTION: Thank you so much. I usually keep the plant outside until it buds . Last year I brought the plant inside to enjoy the smell and show it off more as it began to bud and flower. It developed a horrible case of spider mites with white fuzzy stuff on the buds and flowers and this definitely shortened the flowering time. This year Ive trimmed away the ugly foliage and I try to wash it down with heavy watering occasionally. I've even taken a vacuum to it to clean out webs and dirt. I also have used safer soap and neem oil spray about 1x month , occasionally I wipe the leaves with lemon juice. I have 30 + plants and baby them all , but will I be preventing spider mites. When I see the white ucky stuff I clean it up with cuttips dipped in alcohol right away. I got bad spider mites on a beautiful dark purple dendrobium when I brought it inside, and saved it with alcohol cleaning. Appreciate any advice.
Jerry, spider mites thrive in a dry climate and so it is best to mist the plant frequestly when it is inside. While humidity discourages spider mite infestation, since you already have an infestation, you will need to use a miticide to rid the plant of its currently infestation. Safer insecticidal soap is said to be effective against mites as is a product called Cinnamite marketed by Mycotech. The former is basically odorless, while the latter has a cinnamon fragrance. I also like a product called "Eight", marketed by Bonide. Any of the garden market sprays may be fine as long as the labels specify that is effective against spider mites. You will need to do repeated spraying because, even if you destroy the mites with two or three sprayings, eggs will be hatching and the future adults from that hatching will also need to be destroyed.
I am more concerned about the "white fuzzy stuff on the buds" Undoubtedly, this is a mealy bug infestation which can cause far greater damage and can rapidly spread to other plants. They usually are first noticed on the buds because this is an easily accessed place for plant sap. If on the buds, they likely exist elsewhere on the plant, under sheaths, and even in the potting mix. Use your alcohol cleaning to remove the visible mealys and use a systemic insecticide for these. Again, be sure the insecticide specifies effectiveness against mealys. I prefer to use a systemic insecticide which gets absorbed into the plant tissues and kills the insects as they suck on the plant sap. The systemics are effective over several weeks, after which you may need to reapply it. The product "Eight" is also effective against mealy infestations so use of one insecticide can control both the mite and mealy infestations. Be sure to isolate to infested plant(s) from thosee that are pest free to avoid potential transmission.