Archive for the ‘Bad bugs, icky diseases, and operator error’ Category

Latrodectus mactans

Image via Wikipedia

Halloween is rolling around, when tales of spiders abound, weaving stories of the danger from these beneficial arachnids.  Take a closer look, and you’ll realize most of what you hear are myths.

A belief in medieval Europe held that the bite from a wolf spider caused tarantism, a condition where the victim jitters around in an uncontrollable dance, eventually collapsing in exhaustion after three or four days.  This myth helped solidified human fear of spiders.  Yet even though we have such a condition running rampant today, I don’t see anyone hanging effigies of Lady Gaga out to scare people on Halloween.

From some reactions to the sight of a spider, you’d think they were carting off young children instead of flies for feasts on the neighborhood web.  This is nonsense: as any adult knows, it’s hard to hold a squirming toddler when you weigh 150 pounds, much less 3 grams. 

That’s where venom comes in.  Like parking the kid in front of the television, venom keeps prey quiet and semi-conscious until the spider can eat or wrap it up for later (this scenario is anecdotal; I’m not suggesting you park your child or stun it with venom).  Almost all spiders are venomous, but the majority aren’t harmful to humans.

Did you hear the one about the black widow always killing her mate?  Though generally not true, this is my favorite myth whenever I need to remind my spouse of the dangers of annoying me.  In reality, of the black widows in the USA, only one is known to kill the male after courtship: the eastern ones, Latrodectus mactans.  Western widows consider it rude to dine on their dates. 

Yet even eastern males often make a clean getaway.  That is, unless she’s hungry – a state that drives females of many species to murderous action.  But if he’s careful and she’s well fed, she won’t kill him. 

Does everybody swallow spiders in their sleep?  According to snopes.com, this myth started in 1993 as a magazine columnist’s demonstration on how anything can be said in email spam lists and gullible people believe it.

Spiders don’t have any reason to get into our mouths, unless you go around with it hanging open so insects can live there.  They prefer drier locations, ones that don’t snore or mumble. 

The biggest myth state spider experts hear is that the Brown Recluse (Loxosceles reclusa) is here in Colorado.  This is completely false, according to Dr. Paula Cushing, Department Chair and Curator of invertebrate Zoology at the Denver Museum of Nature and Science.  Though the black widow is everywhere, few people ask her about it.  Instead, she fields hundreds of questions on brown recluse, a spider whose bite can cause a wound that grows but won’t heal. 

Colorado isn’t part of its natural range, but due to the miracle of the internet, many people think it’s here.  Occasionally it hitchhikes into the state on lumber or in moving boxes, but so far it hasn’t established colonies and settled down to raise families.

Learn more about spiders on the museum’s Spider Survey website.

This post was previously published in the Longmont Ledger.

Read Full Post »

Yellow jackets, a wasp that gets very aggressive late in the season, eat many types of sugars and meats.  Their predilection for sweets creates an interesting phenomenon in fall around trees that are plagued by aphids.   Wasps swarm the tree, flying about in such numbers that homeowners are very afraid.

To understand the wasp, first you need to know the aphids – small, soft bodied, sap-sucking pests of many plants found on most shrubs and trees in our area.  We have several hundred species of these insects, which come in a variety of sizes and colors, from green to black, purple, and red. 

Aphids are greedy feeders, pulling out the sap of the tree so quickly their tiny bodies can’t process all of it.  What isn’t used flows out their back end in a sticky, sugary liquid entomologists politely dub “honeydew.”  Wasps love this yummy treat, lapping up the sugar snack without a thought to its origin.

 If you have a problem with wasps flying around a tree, check it for large numbers of honeydew producing insects – most likely aphids but it could be scale.  The honeydew is what the wasps are after. 

A similar behavior occurred this summer, with wasps scavenging along tomato plants.  On closer observation, I discovered that the wasps were gleaning lerps from the plants, which is excrement left by a different sap sucking insect called psyllids.  Unlike honeydew, lerps is solid, resembling sugar crystals and apparently tasting like them too.

That’s a sweet tooth that’s out of control. 

There’s little to be done about the tree at this time, since the leaves will fall soon and the aphids will go into dormancy.  The time for action is next year, just before budbreak, when you could apply dormant oil to the tree to try and smother aphid eggs.  The wasps will eventually die off, leaving only the queen to survive winter.

Read Full Post »

Some of today’s hottest movies and television shows feature blood sucking creatures out of myth.  Vampires roam through this current pop culture craze, lulling us into thinking they’re harmless, even beautiful creatures that are woefully misunderstood (“they’re sparkling!” my son – a monster purist – moaned in outrage).  

If you were a plant, you’d know the dark truth:  blood sucking creatures do exist, feeding off the life source of ill fated victims.  Dodder and mistletoe stalk the stems of our foliaged friends, and if you don’t come to their rescue, your plants will succumb.

Often called strangleweed, devil’s-guts, and hellbine, dodder (Cuscuta and Grammica spp.) is a parasitic plant that lives off the chlorophyll of others, such as chrysanthemums, dahlias, trumpet-vines, and petunias.  As a seed, it’s harmless and unassuming, lying in wait for a host to take root nearby.  Upon germinating, the seedling gropes about until it touches its victim, then quickly clutches it in a deadly embrace.  

Snuggling up to its chosen host, dodder checks to see if it has the right chemistry and if the prey “tastes” right, dodder implants itself into the host with haustoria.  Through these root-like extensions, the hellbine feeds, drawing water and food from the hapless plant.  When implantation is complete, dodder continues to vine up and over the victim, letting go of its connection to the soil below.

Though it doesn’t have the public relations power of its holiday cousin, dwarf mistletoe (Arceuthobium spp.) is a well-known parasite in Colorado forests.  Like dodder, these leafless plants lives off those we love by colonizing Douglas fir and ponderosa, limber, pinyon and lodgepole pines. 

Implanting itself into the trees with “sinkers,” dwarf mistletoe slowly drains the life out of its host (something my son can relate to, having endured this summer’s popular vampire romance movie to please his date).  Look for the yellow- or brown-green segmented shoots rising from infested branches.

To please those who feel dread creatures just need a little understanding, let’s look on the bright side of these parasites.  Dodder is a pretty little plant with slender, delicate stems of yellow or orange (occasionally they’re blushed a trifle red, but ignore that – it isn’t blood).  Though it has no leaves, it does flower, wreathing itself in pinks, whites, and yellow to disguise the fact that it’s producing new spawn from seed. 

And dwarf mistletoe has one trick that’s a sure crowd pleaser:  it spreads its seeds by canon fire.  Blasted from their fruit at near 60 mph, the young splatter the forest in a gluey mass, sticking to anything they hit: branches, birds, or hikers.  If it happens to be a suitable host, the seeds germinate and begin to feed.  Watch for this phenomenon in August and September.

 Drive a stake through the parasite if you’d like, but control for either really relies on removal.  Prune off infested tree branches or pull and destroy dodder infested plants. 

This post was previously published in the Longmont Ledger.

Read Full Post »

Parsleyworm Normally, when an insect attacks the vegetable garden a gardener’s revenge is swift and decisive. Although we don’t mind sharing, some bugs take more than their portion, stripping plants to the point where we have to show them the door – or the neighbor’s garden – and order them to leave.

But this summer a beloved insect is back on the plants, nibbling on members of the carrot family and delighting everyone who sees them. Blaring their presence with a striping of black, white, and yellow, the parsleyworm (Papilio polyxenes) is one visitor you might want to let stick around.

When little, this caterpillar’s coloration has it dressed up like bird droppings, something that makes predators think twice before eating it. If the predator is determined to chomp them, the parsleyworm has another trick up its sleeve: they push a pair of orange, smelly “horns” from their head. As long as you’re not sniffing their head when they do this, it’s an endearing trick.

Yes, they’re eating the parsley. And the dill, fennel, and carrots. This is a small price to pay for nurturing the Black Swallowtail butterfly, which is what these very hungry caterpillars grow into. Should you want to control them, pick them from the plant or spray with Bacillus thuringiensis (Bt), an organic insecticide.

But if you choose to let these lovely creatures live to become adults, don’t worry if your caterpillars disappear from the plants. After stuffing themselves, the caterpillars roam about, looking for a place to spin their chrysalis in which to pupate. You’ll see your parsleyworm again, this time as an adult, a large black butterfly with yellow and blue spots.

 Flitting through the garden, sipping nectar and visiting flowers, this butterfly and its two close relatives, Tiger Swallowtails, are as welcome as fireworks on the Fourth of July. Attracting them to your garden is simple: plant food for the caterpillars to eat, such as parsley, carrots, or dill for Black Swallowtails and willow, green ash, or chokecherry for Tiger Swallowtails. Don’t forget to add in flowers to give adults nectar to sip, particularly butterfly bush (Buddleia spp.), geraniums, butterfly weed (Asclepias spp.), or zinnia.

After all, you don’t mind sharing, do you?

This post was previously published in the Longmont Ledger.

Read Full Post »

Every family has them – the bad apples of the bunch.  A cousin that gets rowdy at parties or a sibling that seems like a lost cause may have us shaking our heads, tut-tutting while whispering “well, you can pick your friends but not your relatives.” 

So it should be no surprise that even lady beetles, the beloved icons of the garden, have a skeleton in their closet.  Well, actually, they have a lot of skeletons in the closet and they’re all leaves, thanks to the feeding habits of the Mexican bean beetle (Epilachna varivestis). 

Adults resemble large lady beetles, being rust colored with 16 spots on their backs.   But the larvae are like rock stars:  bright yellow and covered in huge spines. 

This bad bug feeds on the undersides of leaves of beans and soybeans, rasping off the green tissue and leaving  lacy, skeletonized remains.  If enough beetles gather for a food fest, beans and stems can be attacked and destroyed.

Adult beetles over-winter garden debris, emerging from when beans sprout through mid summer. Eggs are laid on the underside of leaves in clusters containing up to 60 eggs, hatching in one to three weeks.   Larvae then feed for two to five weeks.  There are several generations per year.

July and August are when we see the most damage, so scout your plants for signs of the critters.  Control them by hand picking and dropping them into a bucket of soapy water, or if you’re a bit squeamish about squishing, spritz the larvae with insecticidal soap.  Meticulous cleanup of the garden in fall is a must for keeping these pests from overwintering in your yard.

Read Full Post »

 “May you live in interesting times,” is a curse that seems to dog gardeners this summer.  If late snow, shredding hail, and humid conditions weren’t enough, Mother Nature is now sending a wave of insects to perk things up in the tomatoes. 

Tomatoes top the list for most kitchen gardeners, ranking number one in popularity across the country in a recent National Garden Bureau poll.  With thousands of love apples blanketing the area, it’s no wonder the Front Range is a hot place for psyllids to take their summer vacation. 

These tiny tomato boogeymen have begun assaulting plants this season in what may be the vanguard of thousands of migrating psyllids (Bactericera cockereli).  Dr. Whitney Cranshaw, Professor of Entomology at Colorado State University, has seen large numbers of these insects several parts of the state, including Larimer county.  Sightings of the insect have also been reported in Louisville and north and south Boulder gardens.  

A classic sign of psyllids is their waste, called lerps.


The aphid-sized adults are lovely, with jewel-toned eyes and dark abdomen banded in white.  Their young, yellow at hatching, gradually turn green with each molt; being flat and elliptical they look like scale.  Though adults move about actively and fly in migration, the young are sedentary, content to sit quietly, feed, and excrete white, waxy frass that resembles sugar. This is their waste, called lerps, and is an easy to see clue that your plant is being attacked. 

We should prepare for their arrival in our area soon, since these small, winged sap-feeding insects have toxic saliva that causes the plant to grow oddly.  Look for leaves turning yellow with purple veins, fruit that’s small and tasteless, or the plant appearing as if sugar were spilled on it.  

  Start scouting your plants, carefully checking them for insects or disease every three days until you spot signs of trouble.  Psyllids can mean big problems for tomatoes, severely stunting fruit; so at the first sign of them begin spraying plants with insecticidal soap to keep them at bay.  Coverage of both upper and lower leaf surfaces is crucial to control, and may not be enough. 

Dusts of sulfur can help, if care is taken to cover all leaf surfaces, but should the insects get the upper hand, stronger products with pyrethrin or esfenvalerate can be used.  

 Several diseases show up in gardens at this time.  Green plants turning blonde by yellowing from the lower leaves upward should be closely examined.  If they have brown spots with concentric rings, suspect early blight (Alternaria solani). 

Water, insects, and gardeners spread this fungus.  Pick off diseased leaves and keep the ground free of debris. Dust healthy leaves with sulfur to shield them from infection.  Once the plants have gotten three feet tall, pluck off leaves in the lower foot to prevent the spreading climb of the fungus.  Give plants room to grow without crowding them, and use drip irrigation to prevent splashing water.   

Black, sunken, rotten spots on the bottom of fruit are blossom end rot, a disorder caused by poor uptake of calcium.  Though calcium is plentiful in our soil, irregular watering and excessive heat prevent the plant from using it.  The key to control is watering consistently, so use a timer to automatically turn on and off the irrigation.  Mulch plants to keep the soil from drying out too rapidly.  

More information on tomato troubleshooting can be found on the Colorado State University Extension website.

Read Full Post »

 The worst time for a gardener to take a vacation is during the summer.  Not because you’ll miss the blossoms or there are too many chores to be done; those can wait a week or two and friends can text you photos of the flowers.

No, what happens when gardeners takes their eyes off their plot for a few days is that the scourge of Western civilization takes over your yard.  That scourge is field bindweed (Convovulus arvensis), the best-known and most hated weed to stalk our gardens.

Despite being a member of the morning glory family, there’s nothing glorious about it.  It snakes through the garden.  It entwines itself through branches, drapes itself along trellises, and coils into every nook and cranny.  Nearby plants are smothered, reduced to objects of support for the cheerful-blossomed horror.

Pulling this plant results in a nightmare out of Greek myth – nodes along the roots spring up into a hydra-like mass of vines from the single plant pulled.  Battles with bindweed are epic and are a common thread between gardeners.

The amount of bindweed in my perennials is not so much a nuisance as it is a coup; this plant clearly has visions of holding dominion over this garden.  It lays egg-shaped capsules in the soil stuffed with eight seeds per capsule, something that has me believing those who claim this is really a creature, not a plant.

One friend suggested an approach to conquering bindweed: snip the bindweed back, leaving two or three sets of leaves, slide a coffee can with both ends removed over the weed to protect other plants around it from harm, then paint herbicide onto the bindweed.  For a gardener with a lot of time and not a lot of bindweed, this might work. 

I’m opting for pulling repeatedly and frequently, until the plant’s energy in the roots is exhausted and can no longer regenerate.  Obviously the bindweed has the same thought, and by extending its roots 20 to 30 feet in many directions, is succeeding in exhausting me.

Stamina and dedication are required in pulling to control this plant because it must be done thoroughly, leaving no trace of bindweed growing along the 30-foot span.  Any plant left on this long root system feeds and replenishes the root, supporting the birth of new siblings to resume the hostile takeover.

This is where control gets entangled with neighbor relations, because a root this long means a gardener with intent to eradicate might end up two yards down, trenching through lawns, rose beds, and children’s play boxes.  Unless you want to be hauled off for the safety of the neighborhood, stick to your own yard and practice pulling or hoeing up the plants every 10 to 14 days.  This will keep the infestation to a livable level, and your garden relatively bindweed free.

This post was previously published in the Longmont Ledger.

Read Full Post »

Brace yourselves for the strip show of summer, coming soon to a garden near you.  With tiny jaws and a will to chew, insects intent on turning your garden into an all-you-can-eat buffet are on their way, struggling up out of the soil as the weather warms.  First to lose leaves will be the evening primrose, then sumac, tomatoes, cabbage and potatoes.  

When flea beetles arrive, your garden will be a hot spot of trouble.  Hordes of these small, shiny bugs chew leaves to a nub, threatening the survival of fledgling plants.  Just mention them and gardeners panic, dusting and vacuuming the garden to get rid of the vermin. 

If your seedlings are going to survive, you need a plan to thwart the flea beetle attack.  But with this bug problem, there’s no quick fix.  Like swallows to Capistrano, the beetles keep returning, so several methods should be used to help your plants grow large enough to ward off harm.

What:  Wrap vegetables in floating row covers that allow sun and water, but not insects, to get through.  

Results:  These fabric tents keep insects out, as long as the bugs are not already on the plant.  If your plants are hosting the party already, clean out the buffet first.

What:  Vacuuming the seedlings.

Results:  Hand held dust busters do an excellent job and are easy to move around the foliage.  As an added bonus, the small capture bag can be quickly emptied of bugs into a plastic bag for disposal.

What:  Diatomaceous earth

Results:  This powder, made from crushed fossilized diatomes, is a good way to repel flea beetles.  The dust irritates the body of the bug and they hop off to find less grating haunts in your neighbor’s yard.  Since plants keep sending up new growth, the dust needs to be reapplied often. 

What:  Spinosad

Results:  Spinosad, a fermented by-product of microscopic actinomycetes (bacteria found in the soil), stops bugs cold.  For it to work the bugs have to eat it, which means beneficial insects that don’t eat plants are safe from harm (caution: don’t use this on plants in bloom, or it may harm honeybees).  Once the bad guys have eaten Spinosad, their nervous system gets overexcited, and they drop dead within hours. 

What:  Neem oil

Results:  As a repellent, neem, an extract of the neem tree, can slow feeding of flea beetles.  But it must be reapplied often and doesn’t affect the larvae, many of which develop in the soil.

Act early to protect your plants from attack, and practice safe gardening by reading and following directions on the label for all products. 

This post was previously published in the Longmont Ledger.

Read Full Post »

Spring brings out an odd assortment of turf problems, with persistent Necrotic Ring Spot and mites headlining the show.  But this year I got called out to a lawn where something special is going on – I had the rare treat of seeing greenbugs in action.

Greenbugs (Schizaphis graminum) are aphids that suck the sap out of lawns, turning the grass a rusty orange color.  Like many outbreaks of aphids, this one is accompanied by Ladybug larvae doing their best to eat them.  Upon seeing the hundreds of ladybugs on thousands of aphids crawling across the lawn, the only thing I could utter was “cool!”

If only the homeowner was as thrilled as I was.

You see, the scene playing itself out in his front yard is better than any reality show drama; there was birth, death, hunting and foraging, all accessorized by a backdrop of translucent orange grass that glows in angled light.  When you don’t see this often, it’s nifty.

  But the homeowner wanted a solution to this problem, after all, these greenbugs were killing the lawn.  The largest spot was nestled under a large pine tree, with a few smaller spots under the Ash.  This is common here, with trees providing some type of buffer that lets the greenbugs survive some winters.  In all, the orange greenbug spot was 10 feet long by five feet wide, and I could understand why this was disturbing the homeowner.

Fortunately the cavalry had arrived, and the ladybugs were doing a good job of cleanup; my main challenge was helping the homeowner to accept that, if given time, those ladybugs would clean up the mess.  Armies of insects duking it out on the lawn isn’t everyone’s suburban dream show.

He was very positive about the process and willing to let nature take it’s course, once he crouched down to see the ladybugs in action.  There’s nothing like watching the black-with-orange spotted, spiky creatures wind around grassblades to chomp an unsuspecting aphid.

In other areas of the country, greenbugs are a much bigger issue, but in Colorado, they’re more of a novelty.  Our winters are usually too cold for them, and this colony probably won’t survive another year.  So the homeowner has agreed to wait it out, and reseed in a few weeks when the dust settles out there.

Read Full Post »

A rainy day in Colorado is a rare thing, at least, rare enough that I revel in them whenever they happen.  This week we’ve had a few storms blow through, soaking the ground and coaxing the worms up out of their burrows. 

The sight of the worms inching along sidewalks is a welcome one, and strolling into my office I swerved my feet around them to keep from trampling them.  But then one caught my eye; it didn’t look like the rest.  It was gray instead of russet, the belly flattened out like a plate.  It wasn’t hard to tell the front from the back, since it sported a pair of tentacles. 

It was a slug.  A big, slimy garden slug, and it wasn’t alone.  Glancing around, I spotted at least a dozen more of these beasts, oozing their way across the concrete.  As an entomologist confronted with such a creature, I uttered a technical term we like to use: “Eeewww.” 

Having voiced my fear, I went inside the office and ignored the gathering horror outside.  Slugs disappear if you pretend they aren’t out there.

But more rainsqualls came through last night and today I discovered that, like gastropodal puppies, the slugs had followed me home.  Gliding across the driveway, sliming the sidewalk, the slugs were everywhere I looked while frenetic Alfred Hitchcock music pounded through my head.

Clearly they aren’t limited to the vegetable garden, which is the only location I’ve battled the beasts.  They’re overrunning the perennials and beaching themselves on the bulbs, oozing around the front yard and scaling the back fence.  The only place I didn’t find them was on the bindweed choking the lawn, which makes sense because invading monsters rarely cozy up to one another.

  In a panic, I reached for the heavy artillery – beer and pans to pour it in.  Crooning a “come and get it,” at the creatures I dispensed this liquid like a bartender on St. Patrick’s day, moving from customer to slimy customer with a smile pasted on my face.

With luck they’ll belly up to the beer, where they’ll plunge headlong into the fermented beverage and drown my sorrows.  I’ll know how successful I am tonight when I get home to check the pans.

Read Full Post »

« Newer Posts - Older Posts »