Mystery Fly and Scouting

February 8, 2002
Scouting is one of the hardest and most interesting jobs in an IPM program. The role of the scout is to systematically exam periodic blocks of plant material, assess the population of pests and beneficial and note the general health of the plants.

The most important skill that I have found is the value of remaining still. If you keep moving your eyes around it is often difficult to see something small that is moving. If you keep looking at one spot then often something will appear and can move into your field of vision. If something appears on the periphery then you can shift your eyes to that position and then re-focus. Patience is an absolute necessity.

Naturally with time you will learn the spots that are most likely to harbour the pests or benenificials. For instance thrip like spots that are cryptic. You will find them inside the depths of a flower or inside an unfolding young leaf at the growing tip.

So after scouting a greenhouse yesterday my count was, 3 Amblyseius cucumeris (thrip predator), 1 Hypoaspis aculeifer (soil dwelling thrip predator), countless Aphidius colemani (aphid parasite) and many springtails (small, harmless soil dwelling insects).

One thing that I scouted was a small fly, orange in colour with brilliant red eyes, striped abdomen with a dark tip and hardly any antennae. I had thought this creature was something called Eretmocerus eremicus. All last season I had identified him as such but this year he showed up before I had introduced any (Eretmocerus). When I looked more carefully at him it was clear that he was not Eretmocerus. They were congregating on the aphid banks so may be an aphid predator but after a couple of phone calls I still could not identify him. He has very active predator like behavior. So if someone out there is missing a pretty red-eyed fly please let me know!