Black Bugs on Tomato Plant, Part III - Using a Keyboard Vaccuum to Kill Flea Beetles

Amy,

Your birthday gift left me initially puzzled -  a computer vacuum with 9 different attachments - but then I remembered your advice about the flea beetles.  Of course, it is a bug vacuum.  :)  It works surprisingly well on the flea beetles.  Here are some action shots: 

They kept hopping around inside the vacuum.  For everyone else out there, this tiny little garden tool is the Dirt Devil Detailer and it's about the size of a banana.  The suction feels quite light, which is good because it caused no damage at all to the leaves.  In fact, it barely pulled on the leaves when I vacuumed the bugs.   

As I dispensed flea beetles, I happened to come across that exact same mystery bug from last year.   At least, I think it's the same one.  The one with clear wings.  Interestingly, I tried to vacuum it up but couldn't.  Perhaps it grips the leaves??  I took two pictures, one from the side and one from the top:

I saw at least 3 on my tomatoes today.  However, there doesn't actually seem to be any damage associated with them.

--Rachel

Black Bugs on Tomato Plant Revisited - ANSWERED

Amy,

Last year I posted a question about mysterious black bugs on my tomato plants, and we never got to the bottom of it.  The bugs are back - this year even worse than before.  I found them on my potato plant too.  The damage looks like many small holes.

Here are pictures of the plants and damage:

Potato Plant (this first one I think they're mating):

You told me to capture one of the bugs, put it in the freezer, and then take close up pictures of its mouth parts.  As I tapped a few of the bugs into a tupperware for freezing, I noticed the bugs move almost like fleas.  They hop super fast.   You see the bug, then it vanishes and reappears a few centimeters or inches away.  Even so, it wasn't difficult to capture a few of them. 

Unfortunately, I didn't get any good pictures from the frozen bugs.  My camera takes pretty good closeups, but the bugs are so small I couldn't get pictures with any resolution of their body parts. Instead, I tried to get a few more pictures showing them on the leaf:

That's the best my camera can do.  What do you think?

--Rachel

ANSWER:

Hey Rachel,

So, this is a different kind of "little black bug" than the one from last year. I'm still not sure what those things were, but they definitely weren't beetles. These are clearly Flea Beetles. These little guys are kind of cute, but they can do a lot of damage to seedlings.

You can tell these are beetles because of the hard shell that covers their wings. It's called a carapace. If the insect is at rest, and you can still see clear wings, then it probably isn't a beetle. If you see a hard shell, it's likely a beetle. I was already thinking flea beetle because they are so small, but you also discovered how they got their name: They jump like fleas!  The damage also fits. Flea beetles are one of the relatively rare pests in which the adult causes the most damage. They chew the leaves and create holes we call shotholes, because it looks like buck shot (rabbit shot? tiny thing shot? I don't know much about shotguns).

Look familiar?

They're a common pest in spring and early summer. The adults lay eggs in cracks in the ground around the plant. The grubs feed on plant root hairs, but they rarely do much damage. It's the adults who cause the most problem, chewing through seedling leaves. They don't usually hurt an established plant, which can handle a surprising amount of damage without dying. Well, if they chew holes in a beautiful lettuce plant, it probably still sucks. With a tomato plant's leaves, though, you're probably ok if the plant is established. If it looks like they are really hurting the plant, there are a few options.

Control:

These guys don't respond very well to pesticides, and they're also pretty good at evading natural enemies (the jumping thing). It can make it difficult to control them. Some people put out sticky traps (those yellow cards covered in resin), but I've heard they don't work very well. Diatomaceous Earth works really well on beetles. It scratches the wax layer on their exoskeletons and makes them lose water. You can apply it to the leaves. It shouldn't hurt the plant. The only problem is that you have to apply it after every rain or watering that gets on the leaves. Row covers or any kind of mesh cover will work to exclude them in the first place. If you ever have them on your seedlings, then this is a great way to control them. You can try it on established plants too; you just need to remove them sometimes for pollinators. To be honest, though, a lot of people vacuum them.  Do you have a handheld DirtDevil or anything like it? They work really well, because they won't suck up the plant leaves. You can use a regular vacuum attachment, but you'll need to be really careful that you don't damage the plant leaves. Just hold it at an angle pointing to the sky above the plant. When you do this, make sure you don't block out the sunlight. A good shadow will make these guys scatter. Part of the reason they are difficult to control comes from their ability to disperse quickly. So, try to sneak up on them. I've never tried it myself, but I've always wanted to give this particular piece of advice. (Mostly because it makes me giggle to think of stalking tiny beetles with a vacuum cleaner). They actually make bug vacuums, which are mostly for kids or people scared of bugs in the house. These are probably over-priced for what you get. We used a keyboard vacuum (you know, the kind that picks up dust) to remove moths from the wind tunnel in grad school. It worked really well.

Now I'm going to go back to the previous black bug post to look at the damage again. I think some of the damage may look like flea beetle damage. If they hid when you approached, it's possible that your picture was of the wrong culprit.

Love,
Aim

The Potato Murders

Aim:

I've always figured that potatoes are so plentiful and cheap year round, why grow them? Especially here in the Northwest, with spudsy Idaho just next-door. We've got enough potatoes to power a satellite radio.

And then I ate some super fresh just-out-of-the-ground local new potatoes from our farmer's market last year. Carlos roasted them with some olive oil, sea salt, and fresh rosemary. Holy potatoes! Rich delicious food of the gods. The potatoes were the side dish of that meal, but they are all I remember. I felt I had discovered a whole new vegetable (tuber, whatever).

So in early March, we were in the garden center browsing for veggie starts and seeds, when we came upon the wooden bins full of seed potatoes. It felt like a grocery store - you grabbed a handful of potatoes and put them into brown paper bags for weighing at the register. But the thought-bubbles above our heads were filled with visions of putting a single French fingerling into the ground and waiting for it to magically multiply, and buying some wooden bins of my own to keep in our cool dark garage to store the bumper crop of potatoes through the winter, and at Thanksgiving proudly informing the guests that the mashed potatoes on the table came from my garden . . . and so on.

Things went swimmingly for a while. I cut and planted the seed potatoes according to the guidelines in my trusty "Growing Vegetables West of the Cascades." Their green sprouts popped up quickly and grew fast. I hilled compost around their bases, and they kept growing. And then. Something attacked them, one by one, consuming the leaves, turning them yellow, and eventually, causing the entire plant to shrivel.

At first I thought, okay, I overplanted, so it's fine. I can sacrifice a couple of potato plants and still get plenty of potatoes for two people. But no, the vermin weren't satisfied with just a few, and ultimately took my entire crop (6 plants). I thought it was slugs for a while. And I do think that some of the early damage may have been slugs. But every morning I looked for slugs and didn't find any. Instead, one morning, I found this:

The gooey substance looks like it could be slug slime, but I'm not sure. And what is that little orange bug all about? Is it the dreaded Potato Bug??


Anyhow, I long ago gave up on any hope of potatoes. The plants died before they could even flower. But this morning, as I was pulling some weeds and digging around in the soil, I literally fumbled across - yes! - a yukon gold potato . . . and then another, and another. It's a VERY small crop, but a crop nonetheless.

I cradled them into the upturned tail of my t-shirt, careful not to drop any, and ran inside the house shouting happily to Carlos. We plan to roast them for dinner tonight.


So, insect detective, what/who do you think murdered my potatoes in their tender years? I would like to know so that the same thing doesn't happen next year. Obviously, potatoes are pretty resilient, if they can produce spuds like this even after a beheading. Just think what a healthy plant will be able to produce! Thanksgiving 2011 here we come.


Rachel,

Good news first: That is not the dreaded Potato Bug - or Colorado Potato Beetle, which oddly isn't found in a large part of Colorado. What you've got there is a Flea Beetle (I think). Specifically, I think it's a Tobacco Flee Beetle. They don't generally destroy potato plants, but they can vector diseases. Based on damage, you might have had flea beetles on your tomato as well. They prefer tobacco, potatoes and tomatoes. They jump when disturbed, hence the name "flea" beetle. They chew small roundish holes in leaves. They overwinter in debris on the ground, and they attack almost immediately after emergence. So make sure you clean all that stuff off the ground (around your tomatoes too) when you're finished with them. Maybe even turn the soil over this fall.

Insecticides are rarely necessary. You could cover the young seedlings next year. Once the plant is established, Flea Beetles rarely do much harm. Hilling the mulch around the stem helps to prevent populations. It can also cause some problems from molds and other diseases if applied too early. A tin foil mulch seems to work well. Some species really like yellow sticky traps. We normally use sticky traps to monitor populations, but they can help control Flea Beetles. You should buy some anyway, just to see what's flying around when you aren't home.

Fun Fact: plant leaves reflect light smack-dab in the middle of the yellow spectrum, at 550nm. The cones in human eyes interpret this as the color green, because our eyes are pretty green-centric. Leaves are technically yellow. Insects see them as yellow with a hint of green. So, when we want to attract insects, we make cards that are hyper yellow. It looks like the "healthiest" most awesome plant. So the poor little guy lands on it and gets stuck.

Okay, so I don't think Flea Beetles are the primary problem. The goopy stuff really really looks like slugs to me. Slug boards are a cheap and easy way to monitor. Slugs and snails like how damp and cool it is underneath, so they aggregate there (I almost wrote "congregate", and pictured my professors' shaking their heads while murmuring "teliological, Amy." As if I don't anthropomorphize every other sentence. I mean, I just said slugs "like" it.) You can just pick them off and kill them. Another thing that works is inverted melon rind. This is an expensive fix if you do it throughout the season, but works well with an acute problem. Or if you just ate a juicy melon :)














I'm concerned with the yellow leaves. Unfortunately, that's a pretty vague symptom. I did a little research on potato plants, because I don't know much about them. A LOT of attack potatoes that you don't routinely encounter elsewhere. Weeds, nematodes, wireworms, and a staggering amount of diseases. I can rule out most of the diseases, because they affect the tubers rather than the leaves.

I don't suppose you've saved and/or looked at the roots? Nematodes cause yellow leaves above ground, but they leave distinctive root galls. If you have nematodes, you might want to plant a nematode resistant tomato there next year, and put your potatoes elsewhere. Certain ground cover crops will actually reduce nematode populations in the Pacific Northwest: rapeseed, mustard, oilseed radish, or sudangrass. Alfalfa retards population growth. Whether you decide to rotate crops or not, make sure you get all potato plant matter removed from the area, as that can make them multiply. Also, make sure you only use composted manure, as that's a common way they are introduced. Then again, they could have come from your seed potatoes.

It may not even be nematodes. It looks - from the pictures - as though the lower leaves are healthier than the newer shoots. This rules out a number of diseases. Are there streaks, lesions, or powdery things on any of the stems? If not, that rules out a number more. This could have been psyllid yellows. It also could be cucumber mosaic virus (vectored by aphids), curly top virus (vectored by leaf hoppers), leaf roll (which is a seed virus that can be spread by aphids).

To prepare for next year:

Now: Remove all of the potato matter above and below ground. If you can't get everything below ground, then maybe rotate next year. Wherever you plant, you should start with the soil now. This is going to sound weird, but cultivate your weeds. Keep watering the soil to get your weeds to come up healthy. You want to know what weeds grow there. Not all weeds invade the tubers, but some can. If you have any of those, you can treat them. But, for a little while, I'm telling you to water your weeds. In the late winter/early spring, till the soil. Then cover it with a heavy piece of plastic or tarp. This will not only suffocate the weeds, it will also heat the soil for when you plant.

Handling of seed potatoes: Make sure you get certified stock. Sometimes viruses and nemotades come from the seed potatoes. Certified seeds aren't guaranteed to be disease free, but they come from stock that hasn't shown any diseases for a number of generations. Closely examine the seed tubers you choose. When you get closer to buying them, I can give you some pictures of problems to look for. Keep the tubers in your wine fridge, at about 50-55 degrees F, for at least 2 weeks before cutting them. They need about 90% humidity, though, so you might want to keep them on a damp cloth, rotating regularly. If you have them longer than two weeks, keep them in the refrigerator until 2 weeks before cutting. It's best if you cut them when they are just starting to sprout. Make sure you clean your hands and implements between each tuber, so you won't spread any diseases that might be present in one of them.

Planting: Don't expose the cut seeds to intense sunlight or wind. The soil should be moist, at least 45 degrees F, and ideally warmer than the temperature of the seed. This ensures quick healing. If you have to cut the seeds before you can plant, keep them at 50-55 degrees, make sure they are moist, but make sure there's plenty of airflow. Otherwise they'll start rotting. We might look into some possible fungicides to apply to the soil at planting. I'm unaware of any organic options, but they're out there. Too much compost in the soil can exacerbate problems. Too little affects crop yield.

Pre- to early emergence: Monitor for weeds. If weeds become an issue at this point, treatment may be necessary. You can't use vinegar here. This is one of those, might consider Round Up times, but that's another post. At emergence, put up sticky traps to monitor insect populations. We might consider some clear insect covers - although I'm not sure how much light the plant gets. They do a good job of letting light through, but Seattle's a lot darker than I'm used to! Water as much as you need to.

Full emergence: You'll want to keep an eye on weeds, and keep up the sticky traps. You don't want to water as much. Only water if the soil is cracking (does that even happen there?), to avoid certain types of rot to the potatoes and stems. This is a good time to start mulch hilling.

Harvesting: You should kill the vines before harvest, while leaving the tubers in the ground. This allows them to mature. When you're ready to harvest, water the soil to loosen it. This will reduce bruising. Make sure to examine the new potatoes for any damage. They might still be edible and tasty, but they can also help point to problems to anticipate for next year.

Whheeew, that was long winded! I'm sure you know a lot of this stuff. It's mostly new to me, so I figured I'd err on the side of bombastic. You mentioned (one time, I believe) the idea of growing potatoes in barrels. I wonder if that might make the problems easier to diagnose. Just a thought.

Black Bug on Tomato Plant

Amy:

I have never had a problem with pests on my tomatoes until this spring. Some of the tomato leaves have bites taken out of them. Luckily, the recent hot weather and sun have given my tomatoes enough vigor to ward off the effects, but I took a couple of pictures a few weeks ago when I was concerned about them. You can see it in the first picture, below.

I noticed a little black bug on some of the leaves. I used the macro setting on the camera to take a close-up of it. Thoughts?

Like I said, the good news is that most of my tomato plants are tolerating whatever pest it is. It's not killing them completely. But I'd like to know what it is, because it's certainly taking out some of the leaves, which are very important for sugar production to fuel the tomato fruits that will arrive soon.

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Rachel:


I... really don't know what the black bug is. My first thought is that it's some sort of robberfly, which would be good. However, the wing placement is wrong. And it might be a leaf miner you caught while ovipositing. A taxonomist would be able to look at it and say, "Oh, that's a grylloblattid." (Actually, a taxonomist would never say that because grylloblattids live under glaciers, but you get my drift.) Keep an eye on the plant, and let me know if you find any more. If you do, try to get another picture. I should warn you, though, that I'm better at identifying larval stages that are more likely to be eating the plant. Most of the adult pests of tomato (ie insects that eat the leaves when they are fully grown) are beetles. If this is a pest, it's probably a female depositing her youngsters.

I'm more concerned with the tiny green things I can see below that gal. I can't tell what they are from the picture. If you could go out with a magnifying glass or loop and describe them, that would help. They could be psyllids, which are only a few millimeters long, but you said the tomatoes are doing well. Psyllids have toxic saliva, which causes the leaves to turn yellow. They probably aren't causing the holes. So, even if you have a few psyllids, the plant is overcoming them. They could also be little baby leaf miners that the mom just popped out. I really don't know.

Whatever it is, it can cause the plant to produce less fruit.

Let's talk damage: you've got a moth leaf miner, but it doesn't seem too bad from the picture. You've got something taking out large holes. Normally, I'd assume this is some kind of worm (caterpillar), probably a cabbage looper and maybe a hornworm. Cabbage loopers (see left) are small, green and cute. They hang out on the underside of leaves, and chew everything but the leaf stems. Hornworms are big, with a horn sticking out of their butts (see left below). 1 lonely hornworm can do a lot of damage to a given plant, but Home gardens don't usually have more than one or two. These caterpillar eggs are laid singly, and the insects have a relatively large generation interval. If you don't have a heavy infestation, just pick any caterpillars off when you find them. I'd hate to waste any Bt on a plant that's doing okay, because it may be something else. But check the plant. Hornworms will eat your baby tomatoes too. Make sure you check the plant when there is plenty of daylight, but the sun isn't directly shining on it. Early evening and late morning are good times to look.



There are a number of beetles that feed on tomato leaves. The small things I can't see could be flea beetles. They leave smallish holes in leaves, some of them expanding to create bigger holes. You'll see them hanging out all over if it isn't too hot out. Let me know if you find any beetles on the plant. If you find one that looks like the picture on the right, don't touch it. It might have color on it, but the body style will be similar. That's a blister beetle. They cause, wait for it... blisters! I don't think you have any of them. If you find some, let me know. We'll talk pest management then.

Finally, there are leaf miners that can cause holes to appear in a plant as well. I see some "windowing" damage, where all of the leaf is removed save for a thin layer. Sometimes these thin layers get knocked out (by watering, wind, etc) and turn it into a full-fledged hole.

Do me a favor and look closely at the holes. Does it look like they were formed by something taking small bites, and turning it into a big hole? Are the edges pretty rounded?

Look for caterpillars around your tomato plants; look for any kind of beetle as well. If you can find any of the things I circled in the first picture, try to get a better look at them. Also, if you can get another picture of the black fly-type insect. If the damage has changed at all, I'd like to see another big picture of the plant.

Also, I realize this is a little late. So if your tomatoes are doing fine, then just ignore!

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Aim,

You are a major dork. What is oviposting?? It sounds like a scientific euphemism for bug sex.

Speaking of which, the black bugs are multiplying. I examined another tomato plant this evening and found a community of the black bugs. I took some more pictures (see below). Damage-wise, the only thing I can find is some mysterious curling of the leaves. At first I though the curling had to do with lack of water, but no. So, I can't tell if the black bugs are good-guys eating something bad that I cannot see, or whether they are chomping on my tomato leaves, or whether they are just chilling and keeping it real.

But it's a little unnerving to see the congregation of them on my tomato. I'm obsessed with my tomatoes. It's hard not to be obsessed with tomatoes in the pacific northwest, where tomatoes arguably are not supposed to grow, because it is so far away from their native climate. I start them from seed in the late winter and nurture them all the way through the clouds and rain of spring.  I get very invested in seeing them eventually produce fruit.

Anyhow, here are the mystery bugs.

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Rach,

Ovipositing is totally all about sex. Sorta. The sex has already taken place. It refers to when the female deposits a fertilized egg. And it covers all kinds of activities. A leaf miner, for instance, has a structure which slices into the leaf but not all the way through. Therefore, when the egg hatches, the larva is protected inside the leaf. Honeybees have converted their ovipositors to stingers. So a male bee can't sting you, because they don't have the sexual organs to create a stinger. Dragon and damselflies have long ovipositors because they place eggs on vegetation just below the surface of the water. You'll see the male riding piggyback on the female, until she dips her abdomen into the water. He's making sure that another male doesn't eject his sperm and replace it with his own. Some males get around this by pretending to be females. So the other guys don't know that she mated. We call these "sneaky males." Highly scientific term, there. Also, if the female has mated twice, she can manipulate which sperm she prefers while it's all mixing around in her spermatheca (doesn't that sound dirty). Insects have some pretty freaky sex. That's actually pretty tame. Don't get me started on spit balls.... Anyway. uh. So that's ovipositing.

I'm a little confused because I don't see any damage on the leaves. Is there any substantial damage? This morning I was thinking it might be leaf miners. But I don't see any mining going on in these pictures. I'm actually leaning towards psyllids again. They certainly look like psyllids from here. Also, the immatures are so small, they can be hard to see. They cause the most damage in young plants and transplants. They also cause curling of the leaves. Here's a picture of an adult psyllid.

I think I mentioned this earlier, but psyllids introduce a toxin that causes leaves to turn yellow. We don't know think the adults do this. It's possible that you had a pretty large population of immature psyllids bothering the plant, but that the adults are now hatching. They're still feeding, but they don't have toxic saliva. That might explain why the plant doesn't seem as stressed. Of course, these psyllids will reproduce. You might go through another cycle where the immatures damage the plant. It might be strong enough to overcome them at this point. I'd say just keep an eye on it. Maybe wipe off the plant and try to kill as many as you can. If the plant starts looking bad again, there are organic pesticide which seem to work okay. There are natural enemies of psyllids, like the lacewings you're releasing, but they don't seem to eat the psyllids during the time they're dangerous. So, organic pesticides work in a pinch. Specifically the Ensure version of Spinosad. This is a nicotine-based pesticide that's made from fermenting the microorganism Actinomycetes spinosa. It targets the nerve synapses by binding to the nicotine receptor site. (There are some nicotine-based pesticides that are NOT organic, just FYI). It doesn't harm natural enemies. It comes as a spray, so you don't have to worry about eating it. Just clean off the tomatoes, if you spray when you have any.

Oooo also. If you know you have psyllids in the garden, DON"T use any carbamate pesticides on any other plants. Sevin is a common name. They actually promote psyllid populations.