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Posts Tagged ‘insects’

In the warmth of our early spring, landscapes burst with enthusiasm for the season; trees and perennials woke up in a raucous, flower-filled welcome.  Gardeners greeted the spring show with joy, but as plant after plant sent forth blooms we soon went from feeling euphoric to feeling alarmed.

“Wait, wait, it’s only March,” we muttered at forsythia, and “you’re not supposed to be here until Mother’s day,” we told lilacs.  Crabapples ushered in April instead of May while flowering bulbs burst open in a display more like the fireworks finale than a long, colorful parade.

Sure, it was nice, but also disturbing.  After all, Mother Nature has a way of laughing at Colorado.  And this year, she’s in a full belly-laugh, sending snow and freezing temperatures just as we brought out our Hawaiian shirts and flip flops.

The start of our season was weeks ahead of schedule, with horticulturists and gardeners noting a three-week earlier flowering or leafing out.  Diseases and insects emerged early too, making things busy for landscape and tree maintenance companies.

Experts use phenology, or Degree-day models, to predict pest outbreaks; it’s based on the number of days or hours at certain temperatures the pest needs to emerge after winter.  Depending on the pest, we’re eight days to one month ahead of the usual pest problems.  The Emerald Ash Borer began popping from trees at the beginning of May; last year (the first season tracked following its detection here in Colorado) it emerged in early June.  The bug isn’t getting more aggressive, it’s simply following the climate we’ve had this year.

Gardeners should be aware that many pests are active earlier.  And although the recent cold weather might have put a crimp in their activities, those pests are resilient.  Controlling pests before their damage is severe is the best way to sustainably garden, so be on the lookout for potential problems and have your strategies in place to keep your plants healthy.

Here are a few thugs to watch for:

Fire blight is a bacterial disease that’s destructive to apple, pear, quince and crabapple. It attacks in spring, when temperatures reach 65 degrees F and frequent rain occurs. The best weather conditions for this damaging disease is exactly what we just had: humidity, rain, and hail.  This is when masses of bacteria are forced through cracks and bark pores to the bark surface, where they form a sweet, gummy exudate called bacterial ooze.

Insects attracted to this ooze pick up the bacteria on their bodies and carry it to opening blossoms or young branches wounded by pruning, insects, or hail. Girdling cankers – areas of disease on the wood – develop from branch or blossom infections.  Leaves wilt, darken, and curl into a shepherd’s crook. This gives the tree a fire-scorched appearance, thus the name “fire blight.”

There’s no cure for this disease; prevention is the best solution. Fire blight control include use of resistant varieties, cultural practices, pruning and spraying.

Japanese beetles are beautiful but devastating insects that attack over 300 types of plants, including grapes, raspberries, beans, apples, and roses.  Ganging up on plants, they cause serious injury.  Louisville, Lafayette, and Boulder residents have reported the beetles; it’s unclear how widespread they are in our area.  For more information on Japanese beetles and their control, see ext.colostate.edu/pubs/insect/05601.html.

Gardeners with strawberries, raspberries, and other cane fruit should watch for Spotted Wing Drosophila (Drosophila suzukii).   The overwintering females of this fruit fly relative lay hundreds of eggs on ripe fruit.  Upon hatching, the larvae burrow inside, where they feed on the fruit, growing into plump maggots.  According to the Degree-day models, we’re rapidly approaching peak egg laying by overwintering females and the first emergence of this season’s adults.

From egg to adult is a mere eight to ten days, depending on temperatures, and there are several generations per year.  Keep your fruit meticulously cleaned from the floor of the garden and pick and discard overripe fruit.

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With perennials waking and buds swelling, we feel the call to get outside and reconnect with the earth. Each warm weekend we linger longer in the yard, reveling in the emergence of bulbs and blossoms. Yet, just as we feel the season’s change, so do others in the landscape. They’re out there now, getting busy and quietly enacting plans to take over more territory in your yard.

March is the mitiest month, not because it comes in like a lion, but because it heralds the climax of the smallest nuisances in the yard: Grass mites. And between feeding on the lawn and entering our homes, they’ve launched a campaign of annoyance.

Perhaps the most startling natural phenomenon that happens to many of us in the Front Range is the annual migration of clover mites into our homes. Moving by the hundreds, the tiny, bright orange arachnids clamber walls and slide in around windows.

The first appearance doesn’t raise more than an eyebrow, as one or two crawl across the desk. But then two becomes 10 and slowly that number creeps upward, until the warm day dawns when the mass moves indoors, teeming along the windowsill and streaming to the floor.

Normally, I’m not given to fear-mongering, especially about bugs and arachnids. Clover mites won’t cart off the cat for a luau on the deck. But they leave a red-orange smear once squished, and like a chalk outline around the carcass, reminds me of the crawler each time I see it on paper, book, or curtain. Creepy.

Outside, clover mites feed on turf grass or other plants. They’re unremarkable in the landscape; they don’t damage a lot of the lawn. But when lawns are nestled up against the house, the trouble starts, so plan your landscape to leave a barrier between plants and walls.

Within, controlling these mites is fairly simple. Simply place a quarter inch wide line of powder along the window-sill from side to side, being certain that the powder touches the side walls. This barrier, according to Dr. Whitney Cranshaw, state entomologist and professor at Colorado State University, is enough to stop them in their tracks. Any powder works, such as baby powder, corn starch, or baking powder. As the mites crawl into it, they’re rapidly incapacitated and dry out.

When the powder has gotten filled with mites it will turn a light orange color, a sure sign that it’s time to vacuum it up and apply a fresh barrier. Continue this until May, after the mites are actively entering homes.

As you’re battling mites in the home, keep an eye on the lawn, since more damaging mites are at the peak of feeding for the winter. During warm winters, such as what we’ve had, mite populations explode.

Hatched in October, mite numbers increase into winter. As they feed, rasping off the leaf surface and sucking up tender, interior cells, the damage appears as small yellow speckles on the grass blades. As feeding intensifies, the grass becomes straw colored and eventually dies, leaving large patches that don’t green up in spring. Balmy winter temperatures sets mite metabolisms into overdrive, and by this time of year, populations can reach several thousand per square foot.

This damage is often mis-diagnosed as winterkill or desiccation. If you’ve had mite damaged lawn, take a quick look to see if they’ve returned. Check the base of the plant for congregations of them during the day.

If you see them, irrigate the lawn to raise humidity or check with a local lawn care company for stronger treatments. Snow cover doesn’t put a stop to their feeding, since it provides protection, but as it melts, the moisture helps drive off the mites.

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"Tenodera sinensis" Chinese mantis

Image via Wikipedia

As Valentine’s Day rolls around, a frenzied celebration of love grips us.  Wooing and winning take center stage as lovers come out to play, booking cozy restaurants and spending time on activities to heighten attraction.  These snuggles bring smiles to almost every face; that is, unless you’ve been burned by cupid like Lady Gaga, and caught in a bad romance

Like the famed pop diva, not every date is roses and candy, especially if you’re an insect.  The next time you’re feeling blue, look at our six-legged friends, and you might not feel so bad about your love life.

Follow my lead

Dancing With The Stars might be a popular show, but it could be a lot more interesting if they’d pair the dancers with a preying mantis.  The hypothesis that the female rips the head from the male during copulation is not entirely true; it all depends on how hungry she is.  If not fed prior to her date, she might tear the male apart, to nibble on as a post-coital snack.

To overcome this unfortunate fate, the Chinese preying mantis waltzes the female around, hoping to turn her thoughts from dinner to delight.  If he’s light on his feet, the male escapes to woo another lady, but if he trips up, he won’t be returning for a reunion show.

She’s just not into you

Picking up on her mood is hazardous for ground beetles, who say no with a chemical weapon.  When bugged by amorous suitors, less inclined females rebuff would-be mates with an anti-aphrodisiac, methacrylic acid, which knocks males out for hours.  Stunned and helpless, the males serve as a warning to others.

Date my daughter, or else

Blind dates can be hit or miss, but if you’re a honey bee, they’re downright life threatening.  In a typical small hive, one queen oversees twenty thousand female workers.   Males, called drones, are few – up to 200.  Though outnumbered, young drones’ lives are cushy, tended by workers, pampered for the day their services are needed. 

When that day dawns, drones are offered a choice: go forth and mate, or stay here and die.  On their own, they gather in groups, lounging around a bee equivalent of a pickup bar until young queens take flight.  When this happens, males launch, streaking after them to mate. 

If growing up an idle boy toy sounds grand, consider the bride; queens hatch with an attitude.  Those emerging first destroy any un-hatched queens, fight rival royal siblings to the death, contemplate matricide, then take off on a mating flight.  They say personality is everything.

If males are lucky and catch her, the job is a death sentence; unable to disengage, they break off their appendage and plunge earthward, dying.  She sails on, entertaining drone after drone until sated.

Despite these cautionary tales, love is still a many splendored thing. But just in case, remember to pick up the roses and chocolate.

This post was previously published in the Longmont Ledger.

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There’s an assassin in my garden, a bug with a license to kill.  I spied it the other day when warm weather turned the yard into an insect paradise, and everything came out to play. 

Normally, the garden is filled with ladybugs and spiders but on this day, the predator to beware of is the assassin bug.  I was drawn to the spot, not because of a snappy theme song like the one Bond has, though that would be pretty cool; but no self-respecting killer broadcasts its arrival with an orchestral composition.

No, what caught my eye is the fact that the half-inch long, bright green insect stood out against the red leaves of a rose bush.  A true bug (in the order Hemiptera, probably genus Zelus), the assassin bug has a long, straw-like mouthpart that it uses to impale its prey.  This one was a nymph, not an adult, but it still knew what to do when coming across aphids.  With a swift thrust of its beak, the aphid was doomed.

Assassins are common in Colorado, and it’s always nice to see them about.  On this day it, plus other beneficial insects, were out in force.  Check your garden for them the next time you’re out there, and hum a few bars of the man from UNCLE when you see it. 

 Then let it go on its way – they don’t like to get hassled and are just as likely to jab your finger if you try to pick them up.  Assassins, as a rule, aren’t cuddly.

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Occasionally something disgusting happens in the garden.  When it does, even the bravest gardeners step back with a shudder.  Right now – late May – spinach is getting nailed by leafminers.  spinach leafminer

This tiny fly overwinters in the soil as pupa; once spring arrives they molt to the adult stage and emerge, looking for love.  Females then lay masses of white eggs on the underside of spinach leaves (usually the older leaves). 

 At hatching, larvae tunnel into the leaves, munching their way under protection of the top and lower surfaces of the leaf.  There can be several generations per year until the heat of mid-summer.

Sounds harmless, doesn’t it?  Here’s the catch – those cute little larvae are maggots.  spinach leafminer maggotsNow, I like maggots; they’re misunderstood and often maligned.  But these fellows are in my food and because they’re tunneling between the leaf layers, their frass (a nice way of saying ‘droppings’) stays in the tunnel with them. 

Eeeewwww.

 Before giving up on the spinach bed, nip this in the bud by scouting the leaves, looking for the egg masses.  When you find them, crush them.  If your leaves are already infested, pick, remove, and destroy them.  Don’t make the mistake of thinking that picking the leaves and composting them will help – the maggots will continue to develop in the leaf regardless of whether it is on the plant or off.

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