Question
Hi there,

I've just got a couple of questions about my Ficus, and I'm wondering if you could help.

It's a Ficus benjamina - Weeping Fig, braided trunk, about 5' tall and looks like a ball on a stick, last repotted 6 months ago when I bought it.  It's in a bright location, but doesn't really get much direct light though and I water it once a week, a little more in summer (I'm in Australia, so it's hot).  I prune back any messy shoots whenever they need it and mist it regularly (don't know if that does anything though).

A couple of months ago I (stupidly) put it outside for a week.  It got too much direct sun and some of the leaves burned.  I pruned most of them back.

It recently got scale across the side that was burned, maybe a fifth of the tree has been affected.  I've just started treating it with 'white oil' (Yates PestOil), which I've been told to apply weekly for about 6 weeks.  Can you confirm whether this is the right dosage?

The tree is still growing new leaves & shoots, so it doesn't seem too badly affected.  Should I prune back the areas with scale or just leave them?  It's summer here now, would it be ok to prune it back quite hard at this time of year?

I know there's a few questions in there, so I'll thank you in advance for taking the time to answer.  I'm eagerly awaiting your response!

Regards,
Monica  

Answer
Hi Monica,

I am in New York, so I wouldn't mind having some of your hot weather right now!

You seem to be doing a lot of things correctly. Regular pruning definitely keeps a Ficus manageable and is something that many folks have trouble doing.

Dramatic changes in light usually results in either leaf drop or leaf damage. Damaged leaves do not recover, so it is best to remove those leaves and prune back the leggy stems that have lost many leaves. You may want to prune it all the way round just to maintain the symmetry. In addition, it best to prune your Ficus back as much as you can stand BEFORE your treat the scale. If you have already started the treatment, it is not too late to prune. The pruning simply makes the treatment easier and more effective.

Scale can be hard to detect. When they are young these sucking insects are slightly oval, slightly raised, translucent bumps about an eighth of an inch long. They can be found along stems and on the undersides of leaves. They don't look like bugs and don't appear to move. As they get older, they develop a hard, dark brown shell and look like a small mole. As the infestation increases, these sucking insects will secrete a sticky substance called honeydew that falls onto leaves, furniture and floors. This stickiness is the most obvious sign of scale and the one that most people notice first.

The key to eliminating scale is to treat even the ones that you cannot see. That means thoroughly drenching ALL leaf and stem surfaces until they are dripping wet. It is also best if you repeat this treatment all over again in 5 to 7 days to catch any crawlers (the translucent young ones) that you missed the first time. After that, you should check your plant weekly to see if they return.

I do not recommend any pesticides because they are all hazardous to use and not 100% effective against scale. The best non-toxic treatment for mealybug and scale is called Brand X Foliage Cleaner. It is available through Southwest Plantscape Products in California (www.southwestplantscape.com). Their phone is 1-800-333-7977. It is a silicon-based product so it is very slippery. Its ability to penetrate is probably the key to its effectiveness because it gets into the tiny crevices that other sprays miss. I don't know if they ship to Australia.

You may want to try spraying with rubbing alcohol that will help break through the hard outer barrier of the scale and kill it. Mix 1 part alcohol with 5 parts of water. Add a little liquid soap to help it spread. I have found this to be just as effective as oil if it is applied thoroughly.

I am not familiar with Yates Oil or its concentration. If you use it, make sure it is intended for use on indoor plants and then follow the directions carefully. If applied thoroughly, then only one or two treatments should be adequate.

Another good non-toxic spray is Hot Pepper Wax. Its main ingredient is hot cayenne pepper that overheats the plant pests. There is an information website for it at www.hotpepperwax.com.

Finally neem oil works similarly to horticultural oil. It should be diluted with water and Pine Sol to counteract the onion-like odor. All of these are available nationwide at plant and garden centers and also by mail order.

Important: None of these should be applied to plants in direct sun or in high temps.

Please let me know if any of this is unclear or if you have any additional questions.

Visit my website at  www.HorticulturalHelp.com

If you would like to e-mail me some photos, I may be able to provide some additional insights.

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Regards,
Will Creed, Interior Landscaper
Horticultural Help, NYC

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