Friday, July 16, 2010

Bug News from Whitney Cranshaw

Locally, I have seen a sharp uptick in aphid populations on woody plants and ornamentals in the past week. Not surprising with the wet and generally cool spring conditions. Furthermore, I am not seeing alot of predator activity (lady beetles, lacewings, syrphid flies) so I suspect that the next couple of weeks will see them spiking, crashing when the predators finally catch up and the succulent new growth ceases.

(As a side note I was watching an ash sapling that had serious leafcurl ash aphid injury developing. However, when I checked them yesterday, most of the leaf curls had been cleaned out by earwigs. They completely consumed all the aphids in the curls where they had been harbored.)

However, this may just be a local deal, or at least in places that similarly have had cool wet weather. The situation in much of south east CO is alot different, with some areas in the SE being very dry. Furthermore, I do not see many aphids on the plants in the prairies and last year and several of these sustained particularly high aphid populations at this time in 2009. Particularly the sage, which were loaded with aphids and which subsequently produced most the the convergent lady beetles (Hippodamia convergens) that were in tremendous number in 2009 and moved into Pueblo and Colorado Springs early last summer. (Before settling in the high country for winter dormancy.)

I am also getting a fair number of questions about honeylocust looking odd. I think there are a couple of things involved in many of these. For one, in places where we had the mid-October freeze the trees looked strange all winter with the old leaves hanging on through winter, caught before they could abscise. And a very heavy flowering and seed set is occurring on many plants, likely the response to the freeze in spring 2009 that killed the flowers of honeylocust (and most everything else), causing them to boom more profusely this season.

Then there is the plant bugs, that distort and may kill back the new growth. Although in Fort Collins I am not seeing extraordinary amounts of injury, I would say it is average or even a bit below average here, I am getting reports of more serious damage elsewhere along the Front Range.

And though the plant bugs should now be on their last legs for the season I am bracing for the floodwater-type mosquitoes, which I suspect should come on strong this weekend in Fort Collins.

Ash borers continue to dribble into my pheromone traps. Miller moths (army cutworm) continue to dribble through town. Low numbers for both all year.

Whitney Cranshaw

Fort Collins