Rose Sawfly (or Why Are Little Caterpillars Eating My Roses?)

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First things first: the “little caterpillars” that you see on your rose leaves aren’t really caterpillars. Yes, I know that’s exactly what they look like, but they’re not.

If you recall my “holiday gardening” post about 2 weeks ago, I said that in my climate there were some sawfly larva that showed up between Mother’s Day and Memorial Day in my climate. And here they are.

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This is the rose sawfly larva. It showed up the Friday of Memorial Day weekend. You see that on this leaf (and look closely, because it’s a tiny caterpillar the same color as the leaf. It is on the petal nearest to you) the leaf is just beginning to show a bit of damage. More in a moment about that.

Why is it important that these aren’t caterpillars? For organic control purposes. If you want to spray (I generally don’t; I just let the roses get slightly disfigured because there’s only one hatching of these a season in my part of the world)–you can’t us BT which only works for caterpillars.

Also if you do spray, they tend to hide beneath the leaves, so be sure to get the undersides.

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Otherwise they will leave your leaves disfigured (with these scrape marks that then often get burned into holes by the sun, making it look like some other disease or insect has been there). Don’t be fooled.

The two sets of leaves in the above photo show early damage and more advanced damage. The top set is the earlier damage, although even there, some of the scrapings and holes have been burned or eaten through the leaf.

As you can see in the bottom photo, the mouth scrapings made by the insect are browned by the sun. It’s not a good look.

What can you spray? Insecticidal soap is a nice remedy for soft bodied insects. Just remember to spray in the evening or first thing in the morning before the heat of the day and before most of your beneficial insects might also be accidentally sprayed.

Smooth Hydrangea Pest

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Something’s clearly not right with the leaves of this hydrangea. Several of them are all glued or stuck together at the top.

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If you look at this photo of the peeled opened leaf cluster, you can see several holes that have been chewed in the leaves, as well as small black dots. That’s caterpillar frass (the polite term for its excrement).

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And here, just barely visible, (look for the tiny black head) is the creature known as the hydrangea leaftier.

It doesn’t affect all hydrangeas. As the title of my post indicates, only smooth hydrangeas are susceptible. If you’re not sure what smooth hydrangeas are, they are ones with names like ‘Annabelle,’ Invincibelle Spirit and Incrediball. The botanical name is hydrangea arborescens.

How do you treat these? It’s very simple. You prune them off as soon as you see them. Since this type of hydrangea blooms on new wood, the sooner you catch them, the better it is.

Insecticides are unlikely to work because the insect is so deep inside the leaf pocket so don’t waste your time.

The sooner you get them, the fewer you’ll have. So keep your eyes open if you have this type of hydrangea. A little preventative pruning goes a long way to keeping them happy!

Sneaky Little Devils

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One benefit of some extra time on my hands is that I managed to catch a very strange mites infestation. You can see the freshly showered plants here.

I am not sure if you can distinguish it, but all these plants are in the ficus genus. What’s interesting is that they are scattered around a rather large room with other plants in between that are not affected.

Some of the unaffected plants are a large ficus elastica, one of those very trendy pilea peperomoides, and 4 snake plants.

What’s especially unusual is that the plant in the upper left–ficus ‘Audrey’–has been deliberately segregated all winter because it’s had mealy bugs. Some plants can’t win for trying. But it was way away from everything. How do these mites travel?

I have to conclude that it’s me. They must hitch a ride on my clothing or hands and travel from plant to plant. But at least I have the time to catch this sort of thing right now.

Sun’s Out–Time to Check for Bugs

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If your plants look like this, take a closer look. I did, and by accident discovered the beginning infestation of spider mites.

Luckily this plant is on a plant stand away from most of my plants. I took it to the sink, gave it a good rinse, and put it back on the plant stand.

I do expect re-infestation for a couple of reasons. First, mites breed on a 3 day cycle, and just because I cleaned the plant doesn’t mean that I got every single mite off.

Nor did I get every inch of the stand, or every crevice of the decorative pot clean. You begin to see the issue with something that breeds so quickly.

So since we all have a little more time on our hands, (or at least are spending a little more time at home with our plants), take some care to make sure insects don’t get out of hand.

Who needs one more issue right now?

Houseplants Welcome Spring

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As of yesterday, March 1, we welcomed spring in the northern hemisphere. For those of you scratching your heads because you thought spring began with the vernal equinox on March 19, you’re not mistaken. We’re just talking about 2 different ways to measure when “spring” begins.

Most folks think it begins on the vernal equinox, which is somewhere between March 19–22 each year.

I use the meteorological way of calculating and thus spring begins March 1, summer begins June 1, autumn begins September 1 and winter begins December 1.

In any event, your house plants aren’t waiting for mid-March to know that spring has arrived. They are already responding to the longer daylight and warmer sun.

What does this mean for you? First, you will need to check your plants more frequently to see if they need water, particularly those in bright southern windows.

Next, you will want to make sure that plants that have been fine all winter in an east or west window are suddenly not getting too much sun. This happens to me every year (and unfortunately I don’t have the luxury of moving many of those plants–they just have to tough it out until my trees leaf out).

Finally, as your plants start to wake up, so do little insects. Be alert for this and catch infestations early, before they spread beyond the infested plant.

If you live in a cold climate–even in one that hasn’t had a particularly bad winter–it may be tempting to get outside as soon as you get a nice day. There’s nothing wrong with that. But don’t forget to check on your house plants too. They need you more than ever this time of year.

What’s Wrong with My Fiddle Leaf Fig?

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When I first came upon my ficus lyrata–the botanical name for the fiddle leaf fig–looking like this, I thought that I had underwatered it and my own neglect was responsible for this ugliness.

But after I watered it–and leaves started falling off–I thought “uh-oh. Something else is going on here.” I actually had to get a hand lens to see the spider mites on it–and they didn’t pass my usual test of “shake the plant over a white piece of paper and study the moving dots.” Nothing was moving but there were clearly mites all over it.

So I took it to the shower for a quick bath of insecticidal soap.

What’s interesting–if you remember my post about the web building spider mites covering the mums in my office–last week this plant was fine. And it’s about 3′ tall–you can see that these are not the leaves of a small plant.

Oh well. It will recover or it won’t. I will just have to watch the other plants around it. I am not sure if snake plants get affected. I suspect not, but you never know.

Houseplant Pest Habits

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Yes, those are mealy bugs. Generally they are very easy to deal with, particularly when they are located where they are in this photo. A little alcohol on a cotton swab will wipe them right off.

But that begs the question. Where did this large critter come from out here on the end of the leaf? There are a couple of smaller ones with him (it?)–in fact this whole plant was infested at one point. That’s how I caught these guys so quickly. I was watching for more.

You see, not only do mealies have a nasty habit of hiding in the crevices of plants–places like unfurling leaves and stem/leaf junctions–but their eggs can also live in the soil for more than 2 years.

That’s probably how so many of them sneak into our homes to begin with.

And that again is how we know Stephen King doesn’t garden. Eggs that lay dormant for over 2 years and then become a full-fledged infestation? Sounds like a horror movie to me!

Well, That Escalated Quickly

Whenever I lecture about house plants, I get questions about insects. And I always joke that we know Stephen King isn’t a gardener–and the way we know this is because some of our common garden and house plant insects are so scary that he could write novels about them alone.

I will never forget one of the original X-Files shows. It was about a giant flatworm. The concept doesn’t sound scary but it was enough to make me stop watching the series forever. I said to The Spoiler–nope. I have to garden with those things.

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I was a little appalled when I saw this. I had been closely monitoring this plant. I had seen these flowers wilting one day.

On the second day, the whole plant was wilted. So I gave it lots of water and it revived. Today when I re-visited it to check it for dryness, this is what I found–the entire flower stem covered in webs and spider mites–visible spider mites.

Spider mites are funny creatures. They love warmth, dryness (lack of humidity) and they reproduce every three days. They’re members of the arachnid family–true little spiders.

Some make webs and others don’t. You’re lucky if they make webs–you stand a chance of spotting them quickly.

Still, these are on a plant that’s just a seasonal-type plant that I would quickly discard if it were mine. It’s in my office hallway with several other mums–so no real loss if anything else there gets infected. But I moved them out of the way just to be sure until I have permission to discard them.

What does this tell us? Check your plants–even at times when it seems as if they are not actively growing. Plant pests can become active and get out of hand very quickly–and if you’re not careful, you’ll lose a plant you care about!

Be Ever Vigitant….

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Remember this lovely euphorbia from Wednesday? It’s relatively new to me. I acquired it when I was getting the plants for my container lecture.

I have never been particularly attracted to this type of plant but the coloring was so pretty on this one that I succumbed. This is euphorbia trigona rubra.

About a week ago I was getting dressed and I happened to glance over to the window where this is. The sun was coming in just right. And I thought that I saw something odd on the “thorns.” So I resolved to check it out when I watered later that day.

I am a huge believer in trying to water and tend to your house plants in as much natural light as you can. Here in the northern hemisphere, that’s getting harder to do as we approach the winter solstice. I try to pick a weekend day, mid-afternoon, when the light is good. I discover a lot of things that way.

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In this case, I discovered these: whitefly eggs and larvae. So the plant is now isolated and I will have to treat it with something organic to remove the eggs.

And the quote at the top of this post? It’s one of my favorites from Shakespeare’s Much Ado About Nothing. Dogberry, the ineffective sheriff, is the one who speaks it, about trying to catch miscreants.

The whole thing is “be ever vigitant, I beseech you.” Of course he means vigilant. And if we are to outsmart house plant pests, that’s what we will need to be!

Missing Petals?

I used to have a border of rudbeckia in my wildlife garden. But as in any monoculture, it gradually became a habitat for four lined plant bugs that disfigured the foliage. When other insects started chewing the petals off the bright yellow flowers, I ripped the whole thing out.

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Of course a few have self-sown, but because there is no monoculture, and because they are mingling nicely with other plants (if not actually being overtaken by my supposedly dwarf hibiscus syriacus) I don’t have the problem with insects anymore.

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Interestingly enough, the insects that eat the flower petals seem to have found a container with some annual daisies in it. Almost as fast as the daisies open, their petals are gone.

Here’s a closer look at the damage.

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What’s causing this? In my case, I am sure it is earwigs. They are about the only pest of the numerous possibilities that I know that I have in abundance.

If you are seeing this sort of damage and aren’t sure what might be causing it (and don’t think earwigs are a possibility for you) some other possible causes are the notorious Japanese beetle, or believe it or not, striped or spotted cucumber beetles, which are pests of far more than cucumbers.

I did find a cucumber beetle of the striped variety in my vegetable garden (where I am not growing cucumbers) but 1 beetle is not doing all my damage, surely. I think he ventured over from a neighbor’s yard and probably went right back.

And as for Japanese beetles, this year, I haven’t seen beetles of any kind: not our “June bug” types, nor the asiatic garden beetles or the Japanese beetles. It’s a little odd. (But I am not complaining!)