I always recommend using safe earth friendly insecticides when possible instead of using harsh chemicals especially if you want to eat the fruit. However I have had a Scale outbreak on one of my potted lemon trees and every day my tree is loosing leaves.

Now these are NOT the soft little cute white Scale which you can simply blow off with some water, these are the Armored Scale (red and brown colored). I have tried several non toxic sprays and they really do not work. Today I painstaking took a wet sponge with soap and wiped down all of the small branches ( I know I didn't get them all...because there is simply too many of them!). Certain wasps/bees can help to control them, but summer seems like a long time to wait and I don't think my tree will survive another month or two with out help.

So my question is, if I use toxic chemicals on my lemon tree and don't eat any of the fruit this year, will it be safe to eat the fruit next year? :rolleyes:

I would avoid the toxic sprays. they are not good for citrus. or us. If you spray. what are the odds it gets in the soil and the tree continues to drink it up...?

talk to your local nursery, see what is safe and what they recomend.

I know I spent 2 hours on one plant yesterday. handful of q tips, a bowl of rubbing alcohol... rubber gloves. squished all the scale and really rubbed the leaves and branches down.

A lot of spays wont work great with scale. you really really need to get good contact.


My first recomendation, put the tree in the shower and hose it down with the shower head. getting all areas. or if tree is too big, take outside with the hose.

You might want to check for other insects and they can make it so scale is more happier than we want it

You can mix 2 cups of alcohol with 4 cups of water and spray on the trees. The alcohol seems to disolve the hard shell of the scale insect. This also will not hurt the fruit. You may have to do this several times to get the problem under control.

I can understand the reluctance to use toxic chemicals since have seen people killed by their misuse. However, not all pesticides are the same. There are many in use today that have very short half lives (time it takes for 1/2 to decompose). In addition there are many that are relatively non-toxic to humans or animals-- such as insect growth regulators. Here is some info on one that is recommended for scale on citrus:

"Pyriproxyfen. 1 day PHI.Pyriproxyfen (ESTEEM) is an insect growth regulator used to control cottony cushion scale, although it may require several months to achieve. Pyriproxyfen is also highly active towards the vedalia beetle, a predator of scale.It is applied at rates of 0.11 lbs ai per acre.The restricted entry interval for pyriproxyfen is 12 hours."

PHI is the pre-harvest interval. Pyriproxyfen is the active ingredient-- ESTEEM is the trade name on the product formulation. Insect growth regulators prevent are hormones that prevent insect form molting which ultimatelt causes them to die-- therefore it is relatively harmless to humans and animals.

Cdoc

Cdoc,
Is this a product that would be available to the general public in most all areas, or is it only available by nursery or pesticide license? Most of us here grow citrus as a hobby and are not able to obtain some of the more specialized products. All my citrus are grown in containers as the winters here do not permit year round growing outside. From the above post the product appears to be for an outside, large scale, citrus grove and would be unsuitable for containers. This also sounds like it may kill off the beneficial insects that prey on the scale and other harmful insects. My trees are pollinated by the bees in the spring and summer. Will this product harm the bees and other good insects? While the scale may be a problem, we really don't need to create a bigger one trying to remove a tiny one. In the big scheme the scale is a relatively small nuisance for containers. I can understand a scale problem in a large scale production such as a commercial citrus grove, but unless this is the case I would stick to the less dangerous method of non-toxic, organic pesticides.

I do not know about the availability of this particular growth regulator, but it is not the type of pesticide that would require a license. It is in fact the active ingredient in products used by many on their dogs and cats for flea control.

The point I was trying to make is that many shun chemicals that are quite safe because they are called pesticides. This product has a toxicity to rats that is very low. It takes almost twice as much of this chemical (>5000 mg/kg) to kill a rat as it would take to kill a rat with common table salt (3000 mg/kg).

Your concern about beneficial insects is a valid point that should always be considered. This pesticide may kill some beneficial insects, but that is the case with many other options other than biological controls. Even the alcohol recommended in an earlier post will kill beneficial mites that may even be attacking the scale and is probably even more toxic to humans, although I'm sure most of us would consider that safe. Soap and oil will also kill beneficial insects if applied to them. Bees would not be affected as long as the chemical is not applied to flowering plants.

Cdoc