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Tuesday, August 17, 2010

Lightning Bugs, Singing Insects, and Nostalgia

Aim,

I just got home from a long weekend in the Ozarks with Mom and Dad down at the lake.
Bull Shoals Lake, Arkansas

I flew in to the brand new Branson airport, which was hilarious. It was like walking into Silver Dollar City - the terminal is a cavernous wooden-paneled room with hillbilly hand-painted signs, an artificial creek, and wood-bark rocking chairs. There's also a big sign that says, "Welcome to the Ozarks."

Anyhow, the first thing that hit me when I got to Missouri was a blast of heat and the singing insects.

That's one of the things I miss the most from the Ozarks - the ever-present sound of insects singing and hmmming and shushing and chk-chk-chking and bzzzzing. They are especially cacophonous down at the lake, where the trees are full of cicadas and katydids.

I miss the singing insects so much that Mom got me a CD of them for Christmas this last year. The nights in Seattle are sooooo quiet! There are no singing insects here at all, and I don't believe I've ever heard any in Oregon or California either. What's up with that?

Question #1: Why are there no singing insects on the West Coast?

And then there were the lightning bugs. I just stood outside the first night at the lake looking into the field behind Mom and Dad's trailer watching the little blinking yellow lights. How awesome is a bug that LIGHTS UP?! I remember when we were little girls and we used to spend almost every summer evening running barefoot through the grass catching as many lightning bugs as we could, making sure to catch them with cupped hands so they wouldn't get squished. We'd put them into a glass jar with ventilation holes poked into the metal top to bring to our rooms for the night. Or sometimes we'd just catch and release all evening, until Mom made us go inside and take baths and put calomine on our chigger bites.

Anyway, lightning bugs are also absent from Seattle. :(


Question #2: Why aren't there any lightning bugs on the West Coast?

While I was at the lake, I intended to take a bunch of pictures of bugs for you, but I got side tracked by my general plan of relaxation. I did a lot of swimming with Mom and scuba diving and spearfishing with Dad, although I didn't shoot any fish because the walleye have all but mysteriously vanished this year (another topic for another day).

But I did get a great picture of a green walking stick. Dad found the walking stick in a barn and brought it out for me. It's one of those creatures that seems like a cartoon rather than a real living thing. It's upside down in the picture, so you kinda have to look at it the other way. It has these goofy orange eyeballs that look sort of like eyeglasses, two gangly arms and two legs, and a tall head that is topped by what looks like the hairs on Waldo from "Where's Waldo".

I keep expecting it to say hello and confess its ambition to become a stage comedian with a top hat.



Question #3: Are walking sticks the entertainers of the bug world?

Hehehe . . .



Way,

You are a dork. A cute dork. But a dork.

Anyway....

Answer 1: Singing Bugs
Ahhhh. I miss cicadas. When we're talking in the summer, sometimes mom takes the phone outside so I can hear them.

I don't know why you don't have any singing insects. We have some crickets here. I can tell you why you don't have the loudest and prettiest "singers," though.

I used to call every singing insect a katydid (unless it was obviously a cricket). There are katydids in Missouri, but tons of other species sing as well. Cicadas veritably roar. I called them locusts when I saw them, until my first entomology course. I love them so much. In fact, I brought a cicada carcass with me when I left for Denver. Unfortunately, I kept it on the dashboard of my car, so it fell apart. So did my frozen dragonflies, because something crushed them in the freezer. I had awesome room mates in that they didn't mind bugs in the freezer, but they weren't very careful with them either. But I digress. Cicadas make the really loud buzzing noise at night.

Periodic cicadas show up in the news every once in a while (every 13 or 17 years). Cicadas are xylem feeders - that's the water system of plants. Aphids and others feed on the sugar/food system of the plant, otherwise known as phloem. I've already touched on how inefficient phloem is as a food source. (Wow, this blog is probably bad for my reputation with strangers. I've admitted to tasting aphid poop/phloem and keeping bugs in my freezer!) Anyway. Xylem has even fewer nutrients than phloem, so it takes a long time for cicadas to mature. They spend most of their lives as immatures (or nymphs) feeding underground on the roots of deciduous trees. They don't have any specific hosts, but they need to be deciduous. They also engage in some pretty dangerous practices. Singing is very costly to an insect, because your mate isn't the only thing that can find you. You're also broadcasting your location to predators and parasites. And insect parasites (parasitoids) are pretty nasty things. It's not like getting hair lice. They'll kill you just as dead as a bat, only slowly and sometimes including venom that makes you unable to move while their babies eat you. I'm not just getting gruesome because it's a cool story. This actually pertains to your question.

So cicadas have a strategy to overcome this problem. It's called predator satiation (or saturation). The nymphs are relatively protected, because they hang out underground. The adult males, however, have to literally sing it from the treetops. So they come out in large enough numbers that they can't all get eaten. The predators eat so many cicadas that they're too full to eat anymore. Probably not much consolation to the ones that get eaten, but each individual has a higher chance of survival. The periodic cicadas really go for it. They only come out once every 7, 13 or even 17 years in HUGE numbers. But the dog day (or annual) cicadas do it too. They can live for around 3 years if they aren't killed. And there are tons of them. They're called dog day cicadas because they emerge for the dog days of summer.

And here's why you don't have cicadas. The strategy depends on these large numbers for a given population to survive. And they need a large number of deciduous trees to do it. Cicadas don't do well in coniferous forests. In fact, the don't make it very far into the grasslands of Kansas and Oklahoma, relatively speaking.

I'm going to talk about cicada speciation, so skip to the next paragraph is this topic makes you yawn: Cicadas stretch through most of eastern America, up into Canada. So we know it isn't a problem with climate. You'll also find cicadas through Central and South America, and temperate Europe. Cicadas have interesting speciation patterns in that the North American species seem to be more closely related to those in France than those in South America. It's an old order of Hemipterans. I have had many the argument with an entomologist telling someone that only hemipterans are "true bugs." Personally, I don't think scientists have any right to determine common names. These patterns have something to do with plate tectonics that's beyond me (I get lost after Pangaea). Oddly, there are some species that are extant here and also on islands that have never touched North America (at least, since the dispersal event). This means they must have flown/blown there. Anyway, there hasn't been much change to the songs of species that diverged a long long time ago. There's a good amount of work that goes into studying cicada songs.

Katydids are easy to explain. They don't live in Seattle because it's too cold for too long. They like it tropical, and I guess Missouri is warm and humid enough. Even though it gets colder in the winter. They can hibernate (which we call overwintering, because it's very different from what mammals do). There are several other singing insects in Missouri that need tropical-like conditions. These two are the major players, though.

I don't know why you don't have many crickets. And I just deleted a really long explanation of insect hearing. I don't think anyone (other than entomologists) probably cares why crickets have ears in their knees. My students didn't care when I TA'd the course.

Question 2: Lightning Bugs
I miss fireflies almost as much as singing bugs. There's this really cool trick I'm going to do as soon as I get a group of kids together, collecting lightning bugs. Here I usually take them to streams. Remember how you'd see the occasional bug lighting up in the grass? I always assumed that was a tired firefly. Actually, those are the females. The ones flying around are the males, and they light up in a specific pattern - like Morse Code. If the female is open to mating, she'll respond in another pattern. So if you take out a pen-light, and you flash it the way a female would, you can get a male to land on your hand. No chasing required. Have I mentioned I really want to try this? No kids, even, required.

Lightning bugs require warm, moist climates. The moist part is particularly important. They need damp grass for the female to hang in, waiting for the right guy. You have that there. But. They can't get across the Rocky Mountains. When we were younger, they hadn't made it into the front range of Colorado. It was too dry. There are a few populations that have made it - for the first time - to Fort Collins in the last few years. We can thank global warming coupled with development. Doug remembers a time when no one had air conditioning and the lake froze every winter. Now, everyone needs AC and people water their lawns. So they can support a lightning bug population. It's not in back yards yet - still out in the fields. But the kids can find them if they have parents who know where to look.

I don't think they'll ever make it over the Rockies, unfortunately. Someone might be able to transplant a population there, but I'm pretty sure there are restrictions for that. And they aren't an anthropophilic species, so they won't end up accidentally in someone's luggage.

Answer 3: Stick Bugs
Once again, you are a dork.

They'd be pretty slow moving clowns, as their entire defensive strategy revolves around pretending to be a stick. But they are pretty funny-looking, I'll give you that. I remember thinking they were poisonous, when we were really young and we'd see them hanging out on the bathroom wall at the lake. Funny. That's kind of like that old wives' tale that Daddy Long Legs have the most potent venom, but their mouths are too small to bite you. Pretty silly, all told.

But, yeah, they're pretty funny looking.

Sunday, August 1, 2010

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.

Sunday, July 25, 2010

Lacewings

Amy:

Thanks for the gift of the lacewings.  I released them recently by sprinkling the larvae in several different areas of my garden.  I'll report back on how they are doing periodically.  In the mean time, here are a couple of pictures, including the instructions that accompanied the lacewings. 

Thursday, July 15, 2010

Broccoli Leaves and Aphid Poop

Amy,

Creatures are feasting on the leaves of my romanesco broccoli. The good news is: they left the gorgeous purple broccoli head untouched, and I'm probably going to eat it soon anyway, so no worries. This is the last of my romanescoes this year. I started with six plants, and the other five all matured much earlier this spring. They are delicious - very delicate flavor when steamed and served with butter and salt and pepper. For some reason, this one lonely broccoli took much longer to mature than the other 5. None of my broccoli plants showed any pest damage until now.

I peeked under the leaves and found some aphids (see below). But the aphid population isn't all that large. The picture shows one of the largest clusters that I found. Are the aphids causing the main damage, or is it something else? I would like to know for future reference and also to assess whether the problem might spread to my other veggies nearby, which include swiss chard, leeks, carrots, tomatoes, green beens, and squashes.






Rachel,

So, the good news is that the aphids aren't really a problem. I mean, get them off of there before the population explodes. If you have a few warm days, that little colony could overtake the garden. Seriously. Females can reproduce asexually. Each adult female can produce up to 80 offspring in one week. Each of those 80 offspring then produce 80 of their own, who produce 80 more. That brings us from 1 female up to 512,000 aphids in less than three weeks. Anyway, wipe them off. I assume you already have, but it bears repeating. Do this even though you're about to harvest the broccoli, cause they'll just create some winged forms, pop out a few males, and fly over to your tomatoes to start all over again.

Aphids don't take bites. They have piercing sucking mouthparts. It's like a straw. They insert this straw into the leaf and look for a vein full of phloem. This is the sugar/sap and basic life-blood of the plant. They drink a lot of this. Actually, they drink enough to poop out some stuff that is basically sugar. We call this honeydew. There's a lot of evidence suggesting that the manna the Israelites ate was Honeydew from a particular kind of insect. It's pretty sweet, and not at all poopy tasting. (and I probably shouldn't admit that I know that, but, whatever). Ants will eat it. Ants will actually farm honeydew producing insects, protecting them from natural enemies. So, while ants are not pests, they're a pretty good indication of a problem if you find them all over a plant. Anyway, you can see how the leaf has turned yellowish underneath the aphids. That's typical aphid damage.

About the bites. Are you sure that's not slug damage? I'm less familiar with slug damage. I always look for slimy trails, because I can never remember the size of their bites. Those don't look like smooth margins. You have a lot more experience with slugs than me, so I'll defer. I'm curious about your slug program, though. Have you ever used beer traps? Copper barriers? I've heard inverted melons work really well too.

If it isn't a slug, then it's probably some type of caterpillar. These things are voracious. Since you'll be harvesting soon, let's focus on preventative measures. Look for caterpillars in the early evening or late morning. A little Bt wouldn't hurt, just as a preventative for your nearby plants. I'd suggest that you at least remove all of the leaves right after harvesting. It might be a good idea to remove the plant and turn the soil.

Monday, July 12, 2010

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.

Monday, July 5, 2010

Purple Coneflower

Rachel's Question

Something is wrong with my purple coneflower. All the sepals around the bud are curling and looking mangy. Upon a closer examination, I noticed that there was a very small centipede-looking creature - see the far left-hand side of the second photo. Additionally, there are a lot of very, very tiny white dots. You can barely see them in this photo. Are these two separate pests or are they related somehow?
















Amy's Answer

The "centipede" thing is good. It's an immature lacewing, and it's eating the bad things. Lacewings are seriously bad-ass. They're also very pretty. So don't disrupt anything that looks similar to these pics.

The dots are pest eggs. Wipe them off with a damp cloth. I see some immature leaf hoppers on the plant. I've circled them in the picture. This is kinda bad, actually.

Leaf Hoppers are piercing/sucking feeders that feed on the phloem of the plant (much like aphids, but not as easily removed as slow, clunky aphids). They're hard to treat with a surface deterrent, because they eat the sugary syrup inside the plant. Unlike aphids, they also produce more winged adults, so they can just come back after you clean them off. Do it anyway, though. Look for the rounded little green things and GET THEM OFF. Also the dots.

So, here's the really bad news. Leaf Hoppers transmit Yellows disease to Purple Cone Flowers. Yellows disease is caused by a phytoplasma that reproduces in living plant tissue. It causes, well, yellow leaves, stunted growth, and sometimes a reddish tinge to the leaves. The flowers produced will be sterile, and organs and shoots will be deformed. I don't know if your plant has it, and the only way to tell would be to look for characteristic structures in living plant cells under an electron microscope. I'm assuming you don't have one of those sitting around the house. Also, I wouldn't even be able to tell you what to look for. This wouldn't be such a big deal except that those filthy little (even though they're cute) leaf hoppers will spread the disease to anything else they taste in your garden. Things that are affected by Yellows Disease - in addition to echinacea - include: monarda, caraway, marigold, snapdragon, aster, mum, daisy, carnation, strawflower, carrot, broccoli, tomato, radish, squash, ragweed, thistle, plantain, and dandelion. So you really don't want it in your garden.

There is no cure for Yellows Disease, other than removing the plant. Now, we don't know for sure that you have it. All of this damage could be caused by the leaf hoppers. They like to eat flowers first. If you're really worried, you could sacrifice the plant right away. First, though, I'd like to see if the plant gets better if we treat the leaf hoppers. Try removing as many as you can. Go crazy on the dandelions in your yard, just in case. Check your other plants for leaf hoppers, as well. And watch any new growth on the plant. If you can't see anymore leaf hoppers, and the new growth is still wonky, then you'll need remove the plant.

There are some systemic pesticides out there that minimize harm to other insects - you pour it into the ground and it only affects insects that feed on the phloem. But they aren't organic. Some are nicotine-based and pretty selective in damage due to the type of receptor they attack. The FDA assures us that they aren't harmful to humans. They're probably correct in that, but there is some data indicating that they might be harmful to bees. I only mention this in case it becomes clear you have Yellows Disease and you need to save the garden by killing all of the infected leaf hoppers. This is worst case scenario, and pretty unlikely. Just an FYI.

Meanwhile, I'm going to look for some IPM methods to deal with leaf hoppers. We'll see how the plant does and move on from there."

Friday, June 25, 2010

Leftist Lupine Lodgers

Amy:

I told you about this on the phone the other day. Something is attacking my lupine.

Some of the leaves furl and curl. I noticed that they all furl towards the left. Weird.

Other leaves turn brown. On the brown ones, it seems as though something is eating the chlorophyll, because the leaves become transparent and brittle.

Most unfortunately, the pest also feasted on the lupine's huge flower bud before it had a chance to burst into the gorgeous, showy pink bloom. :(

None of the other plants around the lupine are affected.

What is it?

Rachel:


Very interesting. First thing, let's figure out what the pest is, then we can address how to fix it.

I see some possible damage by leaf miners, but they may only be a minor problem (Get it? I'm such a dork). I'd like you to check for aphids first, as they seem to love your garden. Now I know you already looked underneath the leaves for aphids, cause I've taught you right. But some aphids cause the leaf to curl over the colony, so they can hide from the sun. Some caterpillar leaf miners and fly miners do this during metamorphosis. So, look inside the folds on the leaves.

See what's in there. If you don't find aphids, then try to take a picture. A little caterpillar would be good, because I sent you some Bacillus thuringiensis. So you already have an organic remedy. If you find aphids, then wipe them off with a damp cloth. When your lacewings get there, you can apply some of them if there are a lot of aphids. Otherwise monitor the plants to make sure the aphids don't take over again. If you find something that looks like a maggot, then we'll need to do some more investigating. If you don't find anything at all, then we need to start considering some other culprits, including diseases.

I see other types of damage. Some bugger has been chomping holes in the leaves. The chlorophyll scraping could be caused by leaf miners, but it could also come from mites or thrips. Both of these are microscopic, so you might want a magnifying glass or loop.

Thrips: Some thrips are big enough to see, others not so much. They leave distinctive damage. With a magnifying glass, you can usually see their poops. (Fun fact, thrips is singular and plural. So you can have a single, lonely little thrips.) Anyway. Look closely at the damaged leaves. Does it look like this? Or does it look like there was something between the layers of the leaf? If you have thrips, then there are some things you should do with the bulbs at the end of the season.



If something was inside, you should be able to find an exit hole through the brown/clear part. That would indicate that you have leaf miners.

Mites: I don't see any webbing, but that doesn't mean anything. Mites are really small and hard to see. If you don't have a magnifying glass, try shaking the leaf over a piece of paper. Look closely for a bunch of tiny dots running in circles. (Fun fact about mites: they have sexual reproduction without intercourse, just like fish. The male fashions his sperm into a little work of art - called a spermatophore - and lays these randomly about. Like leaving out chocolates. The female comes along and decides whether or not to insert it.) Mites are hard to treat, but not impossible. You can even order predator mites, which are like mite assassins! They're kinda fun to watch, if you're into watching dots. It requires a little imagination. But I'm getting ahead of myself.

Some things you can do right away:
1. Examine the plant closely, and make note/take pictures of any bugs you find. Afterward, take a damp cloth and wipe down the leaves. Examine the cloth to see if you got anything you didn't see before.
2. Put some mulch down around the plant. This will discourage thrips, some caterpillars, and maybe whatever is taking big bites.
3. If you find caterpillars, use some of the Bt I sent you.
4. If you find aphids, keep wiping them off every day. Apply some of the lacewings when you get them.
5. If you find mites, then keep wiping it down every day. You might want to wear long sleeves and gloves when you do this, or take a shower afterwards. They won't bite you, but it's gross to have them crawling on you when you can't even see them. Feels kind of "itchy and picky".

I really think you'll find either aphids or caterpillars. At least I hope so. If you don't find anything creating the leaf curls, then we'll have to consider some diseases. That's never fun.