Citrus scale

tim45z10January 26, 2010

I was forced to spray 3 of my orange trees for scale. How can I tell if the spraying was effective? They still look the same as before spraying.

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rhizo_1 (North AL) zone 7

How about telling us what you sprayed with. That might help us determine the effectiveness of your efforts.

Adult scale insects can keep their exoskeletons for a long time after they are dead, depending upon the species, of course. Later on the season, see if the 'shells' come off readily with a quick flick. If so....dead.

    Bookmark   January 26, 2010 at 10:14AM
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I used some Malathion I bought at an estate sale.

    Bookmark   January 26, 2010 at 2:57PM
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rhizo_1 (North AL) zone 7

Malathion has limited usefulness as a control for scale insects. It is a contact pesticide, meaning that it has to come into contact with the insect in order to kill it. Scale insects are protected by their waxy exoskeleton, making contact poisons extremely inefficient. Sadly, it is a broad spectrum contact pesticide, meaning that this particular pesticide kills all manner of organisms. It's one of the many chemicals blamed for an upsurge in pest population after its use, due to the killing of essential beneficials.

Also, suspected of being a possible carcinogen and a problem for endocrine systems of mammals, it IS a cholinesterase inhibitor, making it highly hazardous for use unless some pretty serious precautions are taken. It is an organophosphate, a class of chemicals that should be handled with upmost care.

Malathion can be taken into the body by the inhalation of the fumes, splashing of the chemical on any part of the body, etc.

    Bookmark   January 26, 2010 at 10:37PM
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I will dispose of it. I really didnt want to spray in the first place. Help me out on what to do. Thank you for your help.

    Bookmark   January 27, 2010 at 1:15AM
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How big and old is your tree. How bad is the infestation? It'll help if you identify the insect via the net.

I had a moderate infestation on several 3 year old trees purchased from Costco late in the season (enerally a bad move, I don't advise that).

I got rid of my scale by forceful water spraying and manual labor -- but of course the trees were only 6 feet tall with a small canopy and branches were sturdy. The forceful water only took about 25% off. Then I went around and picked and wiped a bunch off. Waited a couple days, new ones formed and sprayed and wiped off. Rinse and Repeat once every few days for a few weeks until they don't come back ( you have to outlast the life cycles).

The ones I had were immobile as adults and were too hard to spot as nymphs and if I recall correctly were San Jose scale.

    Bookmark   January 27, 2010 at 2:15AM
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rhizo_1 (North AL) zone 7

tim, the most most common suggestion regarding scale insects will always be some sort of horticultural oil. If you do a bit of internet research on that topic, you will see that you have many options. (Let me know if you need help, okay?) Horticultural oil options should be readily available at your local garden centers, farm supply stores, nurseries, and/or big box outlets.

Oils work because they can smother the insects in all stages of development. Oils even work to smother the eggs of aphids, whitefly, and other overwintering pests.

Horticultural oils are also considered quite safe for you, for the environment, for beneficial critters, etc. They've been used to prevent (as in smothering eggs) and 'fix' scale infestations for generations.

Be sure to read about and understand that the timing for the control of citrus scale is important, as oils should not be applied at certain times of the year (for fear of damage to flowers, fruit, etc.).

Call your City or County waste disposal department to find out how to dispose of your malathion. It is against Federal laws to pour it down a drain, put it in the trash, etc. Municipalities have a way to help us dispose of hazardous waste.

    Bookmark   January 27, 2010 at 8:51AM
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I will chase down an oil. Thank you for your help.

    Bookmark   January 28, 2010 at 12:42AM
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I am a certified organic gardner and a chemist. I
I have been usung malathion since 1954 and it is much
safer than many "organics" no matter what the crazies

I have a lot of trees and have not sprayed for over
three years in order to protect benificials. Yet I
would not hesitate to spray 1 tbs Superfine or soy+
oil with 1 tbs malathion/gal if needed. Here they
kill more good guys by mosquito spraying than I ever
could. (Tx coast)

What is the infestion rate? Which scale?
A slight infestion may not hurt your trees.

A 10x triplet hand lens is best for small insects,
such as mites and scales.

    Bookmark   January 30, 2010 at 5:17AM
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rhizo_1 (North AL) zone 7

I'll agree that there are many 'organic' products on the market that are far from safe. I do not agree that malathion should be considered safe.

Tim, it IS very much worth while talking about your scale insect population. Any reasonably healthy plant can tolerate a mild infestation. Once you feel that the scales are tipped in their favor, however, it's good to have your horticultural oil on hand.

Be sure to read and follow the directions on whatever product you purchase. Always.

    Bookmark   February 1, 2010 at 2:08PM
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CAstarter(Z9 OC, CA)

Did your oil work? I used 10oz water, dish soap 1 t. and a llittle olive oil. Sprayed on cloud cover cold day. Now all leaves dropping on outdoor Valencia orange. Is this normal do you think?

    Bookmark   February 10, 2010 at 11:47AM
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If you can't find Kneem oil, a good horicultral dormant oil would work wonders. thay make some safe for indoors use. Make sure it says that.

There is a thing called Cedoflora that Logees sells that kills them remarkably..Safe for indoor use.Stinks like mad though.

Watch out for home made concoctions, especially certain oils that can burn your plant days after applied. That may be the reason they sell certain oils for our plants. Some oils specifaclly use for plants leave little residue that hurts the leaves long after it is applied.

    Bookmark   February 10, 2010 at 12:52PM
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"Some oils specifaclly use for plants leave little residue
that hurts the leaves long after it is applied".

Worded better than that...

Professional oils made specifically for plants leave little residue that hurts any leaves long after applied.
I know for a fact that "oilive oil" leaves reside on leaves for days, because days after applied on my gardenias, the sun burned some of the leaves severely. I had to wash those plants off with warm soapy water to avoid any further damage...

    Bookmark   February 10, 2010 at 1:18PM
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I found this blog while checking to see if there might be anything new for organic control. I am a leukemia survivor, so I now avoid chemicals as much as possible in my nursery and greenhouse.

Oil sprays, dish detergent and water sprays will all work ..separatly or together to control scales, aphids and white flies. But, you have to work with the life cycles of these nasty little suckers for long term control. Their life cycles are as short as one week. Aphids are Asexual it only takes one to start thousands...and very quickly. Scale and whitefly are also short cycle reproducers, so daily scouting of your plants and frequent water, oil and/or soap sprayings are essental for continued control.

For those who want long term control, chemicals do work, but do not use them on anything you plan to eat produce off of. Chemicals that are systemic, that contain active ingredients like Acephate, will be absorbed into the plant and remain active a month per application. This breaks the life cycle as the insects are killed while feeding off the sap.

My scale came in through plants I allowed a friend to overwinter in my greenhouse, even though I applied granulated systemic to all her plants as an attempt to protect my own crops. So, always check any new plants for insects before bringing into your home or garden. I would further suggest beneficial insects that will feed on the pest insects. Encourage spiders (ugh), lady bugs, praying mantus, lizards.... use yellow sticky cards to help monitor white flies or fungus knats...

I am off to do some serious scale removial off my meyer lemon!

    Bookmark   April 28, 2010 at 11:00AM
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A hard mist of soapy water knocked the scale right off! Took a bit of work finding the angles, had to go back and pick some off, but the majority were gone when I finished spraying.

There are several gagets on the market to mix whatever you are spraying through your hose. One is called Hozone which mixes at a rate of 17/1, that is what I used this time. I mixed a mild fertilizer concentrate with about three cups of dish detergent in a five gallone bucket and watered the entire greenhouse first with the mixture and then did the high pressure sray using a little trick I learned from a commercial grower....

There are several brands of shut off attachments for the hose, the one I used was a plastic Gilmore. Simply partially close off the valve and you get a fine hard mist that will knock off aphids, white flies and scale.

One doing my morning scouting, I had less fungus knats, found 90% less aphids on my greenhouse plants and only a few remaining scale on my lemon.

I do hope this will be of some use to others.

    Bookmark   April 30, 2010 at 10:39AM
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Spray twice with dormant oil spaced two weeks apart and no more scale for sure. Dormant oil is about as non-toxic as you can get except for scale insects.

    Bookmark   April 30, 2010 at 11:07AM
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Annie, just spraying off pests never worked for me..Some how they always manage to find their way back up my trees, and attack again...Many just fall right back on top of the soil or around the pots..

I also use oil as suggested by Rhizzo, and this has done trick! I have to keep up with the their life cycles to rid them all once and for good..

I was bad and did use Bayer insect control systemic on many in the past that I did not plan on eating when I stuck them outdoors, and boy did they disappear that way too.

But I have been sticking with the oils since I have friends here that care about me and my health that tell me to avoid the chemicals..Thanks..:-)


    Bookmark   April 30, 2010 at 12:16PM
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Scale on citrus is in the areas that are hard to spray, or remove by hand. Most are under leaves and between branch and leaf stem. My little hand sprayer does not work upside down. And if I lift the leaves they often come off.

Do I need to get a hand pumped sprayer? If so what brands have you all found to be good

    Bookmark   May 14, 2011 at 1:53PM
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