Pests and Diseases

A Buggy Time of Year

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I mentioned on Monday that we had had the house power washed recently. That turned out to be a blessing in disguise.

Of course I had to move many of the over 100 house plants that I had brought outside so that they too wouldn’t be “power washed” or damaged in the process.

As I was doing so, I discovered that somehow the mealybug infestation that I had indoors had returned and had spread to several other plants.

Now, one of the reasons why I “summer” the plants outdoors is because a lot of these pesky plant issues have natural predators that are kept in check.

Scale, for instance, is nicely handled by wasps and ants.

And the hose washes off spider mites.

But apparently nothing likes mealy bugs. Doesn’t that figure?

Anyway, I found the problem, isolated the infected plants again, and we’ll see. I have one troublesome ficus that may just become compost at the end of the season.

So I definitely got much more than a power wash from this adventure!

A Rose Virus?!

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For some of my longer time readers, you may remember this photo from last year.

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This is this year. And sadly at least one or two more of those roses is going to have to go. What’s happened? A nasty virus called rose rosette.

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There aren’t really any good photos of what this virus does to roses. It is spread by a microscopic mite–so no chance to see the damage until after it occurs.

Last year the roses looked beautiful. They came out of dormancy this winter looking stunted, with witches’ brooms and oddly twisted foliage and I started ripping them out.

After I filled a whole dumpster with them, I realized that I hadn’t gotten them all, which is how I was able to get a few photos. So I have to go back and take out at least 2 more.

Obviously we will not be replanting roses here, which is kind of a shame because they were happy. Oh well. At least the roses got the virus and not us!

Aphids Are Like Something From Another World

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Ah, here it is Friday again and I am posting about bugs. This is getting to be a bad habit.

This is something that usually happens in late April for us. Aphids are a cool season pest for us, so we will get them in late April (usually) and then again in the fall. I most often ignore them completely because they are usually only on new leaves and once it warms up, I will have a nice robust population of ladybugs to deal with them.

Well, we have had record cold so far this June so I decided that I had better take some preventative measures until the ladybugs got here.

What did I do? I dragged a hose down to this garden and hosed off the plants.

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This is the result. The aphids are almost all gone. You can see that the front shoot has been hosed off and the back one has not–it is still full of aphids.

I would probably not have done it if I hadn’t seen aphids with wings. That told me that the population was so high that it was about to move on to other plants. Since only half the rose garden was affected at this point, I thought it best to try to keep it that way.

Aphids are freaky insects. They are all female and they can be born pregnant with the next generation already waiting to be born.

They come in various colors to better blend with your plants, but green and black are the most common by me.

They are born wingless, but when the population on a particular plant gets too high, they’ll grow wings and migrate to a new plant.

Luckily, they are quite easy to hose off. And once they are knocked down, they don’t generally return to trouble the plant. So I don’t expect to have to deal with this again–at least until fall, at which point, I usually just ignore them.

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!