Saturday, 26 September 2015

[cobirds] Hackberry Psyllid Emergence Underway

Just a heads-up that yesterday at Grandview Cemetery in Fort Collins I noticed the beginning of adult psyllid emergence from galls on the leaves of hackberry.  There are two types, blistergall psyllids and nipplegall psyllids.  The ones I saw flying about (look like tiny gnats when backlit) yesterday were the blistergall psyllid.  Emergence of the slightly bigger nipplegall psyllids usually follows in a matter of days.  At most of the places I've looked all up and down the Front Range and eastern plains this summer, the crop of psyllid galls on hackberry leaves is very heavy.  Fox Squirrels, House Finches, chickadees (both Mountain and Black-capped), and even Downy Woodpeckers have been feasting on the nymphs within galls for the last few weeks.  The ground under many hackberry trees is littered with leaves that show the caps on the nipplegalls bitten off or with beak holes in the purple, flat blistergalls.

We have not had a lot of eastern migrant warblers or vireos yet this fall, but if weather systems ever shove any our way, maybe hackberry would be a good tree to check out for the next couple weeks.

Dave Leatherman
Fort Collins

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