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Posts Tagged ‘aphids’

The first of the aphids showed up in November, a small herd of them clustered on the soft, succulent tips of the hibiscus plant overwintering in the sunny window of the back room. My spouse was concerned, but I pooh-poohed this, saying I’d pick up some insecticidal soap to get rid of the sucking pests.  “A couple of spritzes and they’re out of here,” I said.

Mother Nature loves overconfidence, especially in gardeners who routinely try to bend her to their will. She clearly loved the challenge I threw down, because the aphids she sent to worry my plant are imbued with a resilience and will to conquer that would please any conqueror of yore.

As soft bodied insects, aphids are vulnerable to soaps; it disrupts their exoskeleton and causes catastrophic water loss. In order for it to work, the soap has to coat the body of the bug, so spraying the entire colony is a must to ensure control of the pests.

If you miss any aphids, they’re bound to bounce back quickly. Aphids are parthenogenetic; they can produce offspring without fertilization of eggs.  They’re also viviparous, hatching eggs within the mother’s body and birthing live young.  The young are almost always daughters, who, at the time of their birth, are already maturing their own eggs for offspring.

They’re all girls, nearly all the time, and are born pregnant, which is why their numbers increase alarmingly fast. Nymphs are mature enough to produce their own daughters in an average of 10 days, under good conditions such as a warm place with no predators.

This is exactly the condition in our back room, something that in my overconfidence I failed to take into consideration. Casually, I sprayed the colonies at the tips of the plant.  A few weeks later my spouse asked when I was going to get the soap to spray the aphids, and, puzzled, I said I’d already done this.

“Really? It didn’t work,” he said, calling me to the back room to behold colonies covering both tips and budding flowers.  I sprayed again, to the same results: the soap knocked back some of the aphids, but the colonies returned with greater vigor in a few days.  Muttering and calling the beasts unpublishable names, I attacked again, and again, employing soap and hand swipes to rub the bugs away.

The battle seemed lost, until one day a sight stopped me as I raised the soap bottle. A ladybug, perched atop the uppermost growing tip, snacking on aphids as if they were cookies.  We welcomed this beetle like an honored guest, the two of us hovering and watching her feed.  “Will she get all of them?” My spouse asked, eyeing a bud with a particularly large number of aphids.

She got through quite a few of them, but she didn’t stick around; after her snack she seems to have settled back into the mulch in the pot to continue her off-season rest. We look for her daily, and considered purchasing more to help her out.

But ladybugs come in bags of hundreds and our house is too small to host them; my imagination had them raiding our meals once the aphids were gone in a manner much like the zombie hoards on TV. Other biocontrol options are even less appealing, such as releasing parasitic wasps.  Although they’re helpful in reducing aphids, swarms of wasps aren’t exactly a welcome mat to visitors.

The aphids are still there, but fewer in number; my routine of spritzing them with soap are keeping them at bay until the ladybug reappears. This balance is a good one, and we wait for warm spring days when the ladybug reappears to help out.

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Several insects have popped up in the fruit garden this week, so if you’re growing gooseberries, currants, apples or pears, take a look at what could be bugging them:

 Currant sawflies (Nematus ribesii) have reared their heads in gooseberry shrubs.  A leaf-feeding bug when young, the caterpillar-like larvae are light green with black spots, plus black head and legs – very pretty.  They’re gregarious; in other words, they live and feed in a crowd when young. 

As unsupervised youths, they can do a lot of damage before you notice anything’s amiss. They and a few hundred buddies will eat darned-near every leaf on the plant, defoliating it just when the plant needs that energy to ripen fruit.  At this time of the season they’re more likely to be located towards the interior of the shrub, so check your plants carefully by lifting and inspecting each branch.

Look at the undersides of the leaves for the white, oval eggs and on the leaf petioles (stem attaching the leaf to the plant) for the caterpillars.  Because they are nicely camouflaged by their color, the larvae can be hard to spot, so be sure to look for small holes in the leaves as a clue to their presence.

Insecticidal soaps control these critters, or you can hand pick and dispose of them.  If you choose to use soap, read and follow the label, and make sure you spray it early in the morning, late in the evening, or on a cloudy day so that harsh sun doesn’t cause it to burn leaves.

 Currant aphids (Cryptomyzus ribis) are also out in force, dining on currant sap and distorting leaves.  You can find these small, pear-shaped, soft insects on the undersides of leaves, but the real tip-off is how they make the leaves look – parts of the leaf cup downwards, leaving a distinct puckering along the top.  The bumps and lumps also take on a reddish hue, which stands out like a flag against the green foliage. 

 Fortunately the beneficial bugs are on patrol, and ladybugs can be seen crawling over leaves to snack on the aphids.  But if you’re impatient for control, insecticidal soap or a strong jet of water will knock the aphids down. 

 

Coddling moth (Cydia  pomonella) adults are getting caught in traps, so protect your apples and pears if you don’t want to find worms in them.  As these adults fly they’re looking for love, and once they’ve found it, will lay eggs on the young apples.  After hatching, the caterpillars gnaw into the fruit, munching on the apple insides for three to four weeks (the first flight of adults – those we’re seeing now – will lay eggs on leaves, and larvae eat those first, then worm their way into the fruit).

When it’s time to pupate, the coddling moth caterpillars leave the fruit, crawling down the trunk to find crannies in the bark to spin a cocoon.  Use this against them by wrapping the trunk with corrugated cardboard – the larvae find this a cozy place to pupate.  Take the cardboard off and replace it every two weeks, and dispose of the used cardboard as desired. 

Molasses traps are irresistible to the adults, and you can make your own out of molasses and water in a 1:10 ratio.  Pour this into a wide-mouth container, then hang it in the tree.  Check it often and replace when full of moths.

 

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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.

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