Augh! Aphids and spider mites!

greendreamhomeApril 2, 2014

Two days ago, all of a sudden, the plentiful roses on my beautiful bush suddenly all had dark, dried-out petal edges, including brand-new buds that had yet to open! I saw this at dusk, and I ALSO saw for the first time little green things flying around.

I mixed up a combination of 1 tsp Dr. Bronner's fragrance-free liquid castille soap and 2 tsp vegetable oil in a spray bottle filled with water. I also added and dissolved granulated garlic. (I know you're supposed to make garlic "tea" or oil, but I didn't have time for that.) I sprayed down the rose bush really well.

Last night I didn't see any flying green bugs. However, my little baby orange rose bush, which has its first flowers, also had developed the brown, dried petal edges. So does one of my pots of petunias. (The other petunia pot doesn't have brown edges, but does have some holes in the petals.)

I called the nursery and they said I probably have spider mites. And sure enough, for the first time I saw a little web at the bottom of my big rose bush. The nursery said to wash the plants down very well and then apply my spray. I realized that I would be washing away yesterday's heavy coating of spray, and also that the oily spray might not stick well to wet plants, so I did a little experiment:

I didn't wash the giant bush, but instead resprayed it.

I thoroughly washed the little orange rose bush, and didn't spray it (I'll do it today when the morning sun leaves the area.)

I thoroughly washed AND sprayed the petunias (both of the pots.)

I thought I would get opinions here about what to do, and also ask if the garlic is truly helpful.

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strawchicago(zone 5a)

Hi GreenDreamhome: I applaud your experimenting, and would love to hear the results. Years ago we had a drought, with temp. over 100, my Eglantyne rose had spider-mites from the nursery. Spraying with water didn't help. It was planted near a brick border, which reflected the heat onto the rose. I kept pruning, that didn't help.

Finally I moved it away from the brick border, to a partial shade location, with a wet manure mulch. After spraying with water, I used 70% rubbing alcohol with paper towel to rub off the affected branches. That rose was freed of spider mite, and sprouted healthy leaves.

I checked all the sites on spider-mites, and could not find garlic as effective. From U. of Colorado Extension:

"Spider mites: Symptoms of injury include flecking, discoloration (bronzing) and scorching of leaves. Natural enemies include small lady beetles, predatory mites, minute pirate bugs, big-eyed bugs and predatory thrips.

One reason that spider mites become a problem is insecticides that kill their natural predators."

**** From Straw: Ever since I rubbed off all the branches with alcohol & pruned off the tip ... zero spider-mite in my garden for the past 3 years. I planted lots of Calendula which host green lacewings. Best wishes in combating spider-mites, they are hard to get rid off. From eHow:

"Spider Mite Predators - Three main predators are: phytoseiulus persimilis, neoseiulus californicus and mesoseiulus longipes. All three are effective in temperature levels from 55 to 100 degrees and in humidity as low as 45 percent.

Beneficial Insects - Green lacewings can be introduced to a garden as larvae and will consume spider mite populations. Ladybugs & Praying mantis and spined soldier bugs have been used to combat mites."

Some info. from below link:

"Washing away the mites' webs will interrupt their natural life cycle and prevent them from multiplying. Use a strong blast of water to wash. Do this in the morning for three days in a row. You can use a hand-held vacuum to remove the mites and webs from your plants. After vacuuming the plants, place the contents of the canister in a plastic bag and put the bag in the freezer for several hours to kill the mites."

*** From Straw: the spider-mite infestation of my Eglantyne was so bad that if I had pruned more, it would had been too short. That's why I rubbed the branches & some leaves with paper towel doused with rubbing alcohol.

When I wiped the kitchen floor with 70% alcohol, even ants got killed. The advantage of alcohol is it evaporates quickly, easily washed off, and won't harm beneficial insects introduced later on to the garden.

Calendula seeds are sold cheap & the flowers are pretty & edible & used for medicinal purpose. I also use calendula petals in cooking to give rice-casserole a yellow color. Calendula thrives in hot & dry conditions, and host green lacewings which devour both aphids and spider mites. See picture of yellow Calendula flower that I used in my bouquet, along with red Firefighter rose:

Here is a link that might be useful: Organic ways to stop spider mites

This post was edited by Strawberryhill on Wed, Apr 2, 14 at 18:16

    Bookmark   April 2, 2014 at 5:52PM
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Thanks for all the info! I had the flu this week, so I couldn't really read everything until now.

You rubbed EACH BRANCH with alcohol? I can't imagine doing that. It must have taken you three days!

I think my concoction got rid of the spider mites, but it also chased away what I now realize were lacewings :( But I think I had to do it. Everything in the garden has now been washed well and treated a few times. The big rose bush is still ratty, but thankfully my little orange bush has sprouted some nice flowers that don't have any damage.

If I didn't get the flu I would have gone to get more ladybugs. Although I think the spider mites came from that nursery with my last purchase, some marigolds and sonantas, neither of which seem to be growing. At any rate, I never had spider mites until they arrived.

I will definitely plant some calendula!

About the garlic: it doesn't kill the existing mites; it's supposed to repel future ones. But it does clog the sprayer, so I've switched to a garlic-free mixture for most spraying.

    Bookmark   April 5, 2014 at 12:35AM
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strawchicago(zone 5a)

Hi GreenDreamhome: I hope you feel better (regarding the flu). I only rubbed the uppermost branches with alcohol, that's where the web was. So glad you mentioned marigolds ... they are spider-mite magnets.

I posted in Jan 13, 2012 the info. from Field Roebuck's book, "Complete Roses: Featuring 100 Easy-Growing Favorites". Field Roebuck is a Texan Rosarian. Here are a few tips taken from his book:

1) Put epsom salt in Sandy soil only. Epsom salt is magnesium sulfate. This is correct, since alkaline clay soil like mine is tested exceedingly high in magnesium.

2) The level of calcium is just as important as soil pH. This is correct. I'm next to a lime stone quarry, but my soil is tested barely adequate in calcium. EarthCo., the soil testing company recommended gypsum for my soil. Calcium binds with phosphorus in alkaline clay.

  1. Marigolds are spider-mites magnets, but good for deterring nematodes.

4) The herb rue is an insect repellent, and is especially effective against Japanese Beetles. The book stated that Geraniums also have the same quality.

5) The edible alliums - garlic chives, chives, and onions are effective against aphids and spider mites. *** From Straw: warning, Chinese chives or garlic chives are extremely invasive (spread by seeds). I find that dill are easily grown from seeds, not invasive. I found lacewings, ladybugs, preying mantis, and a toad in my dill patch. Plus dill & tuna & red onion makes a great sandwich for the summer.

6) No need to use loose gravel at the bottom of pots. Field Roebuck recommended using a paper towel to line the bottom of pots, before putting soil in.

7) No need to pick up diseased leaves. True with black spots, rust, and mildew, but NOT true with pests like mites & aphids. It's easier to spread a thin layer of wood-ash on top to suppress fungal growth.

8) Both rock and colloidal phosphates are ineffective in pH higher than 6.4 - True, Colorado State Extension mentioned that both rock phosphate and bone meal cannot be utilized at pH above 7.

Below is a picture of yellow Calendula flower & pink geranium in my garden. The herb Dill attracts even more ladybugs .. dill is just as drought-tolerant as Calendula.

Here is a link that might be useful: Field Roebuck's book

    Bookmark   April 5, 2014 at 5:41PM
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my friends-florists advised me to use some special medicine for plants, but i don`t remember exact name. you can ask them, they are from megaflowers :)

    Bookmark   April 7, 2014 at 4:54PM
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