Mampe: The Eyes Have it in Identifying Phorids


March 1, 2001

By: Dr. Doug Mampe

The Eyes Have It in Identifying Phorids

Q: In many of my restaurant accounts, I am finding small flies that resemble fruit flies. We clean everything, yet the flies still persist. In one particular restaurant, there is the odor of sewer gas in the basement. Could my problem be phorid flies? How do I tell the difference? Will phorids breed in dirty drains? R.A.

A: Phorids and fruit flies do resemble each other. The common fruit fly has red eyes, but other fruit flies may have dark eyes rather than red. Phorids never have red eyes, so any red-eyed fly is a fruit fly.

Without getting into looking for sutures on the head capsule-which will separate them quickly-I look at the wing venation. Fruit flies have several cross veins. Phorids do not. Both have heavy veins along the forward edge of the wing.

Phorids will breed in dirty drains, but so will some of the dark-eyed species of fruit flies. Regardless, cleaning the drains eliminates both species.

If you think you have a break in the waste line, and that phorids are breeding in the contaminated soil beneath the slab, have the drain videoed by a plumber and look for leaks. If leaks are found, the slab must be opened and the contaminated soil removed.

Appeal to Pharaoh Ant’s Sweet Tooth

Q: We have a pharaoh ant problem in a commercial building. We have applied many different baits with limited success. Bait competition seems to be the problem, as the materials handled in this facility have a high protein content and there are residues on tables, walls, etc., upon which the ants feed. We are afraid to use a residual for fear of breaking up the colonies and scattering them. Any thoughts you may have would be appreciated. T.S.

A: Everyone talks about pharaoh ants liking proteins and carbohydrates. They probably do, but with the food competition you have, these baits may not work. I have had great success with sugar-based baits under such conditions. Just like children, pharaoh ants seem to like sugars from time to time. I wouldn’t apply a residual spray unless all else fails.

Sealed Crawlspace Presents Problem

Q: We are encountering American roaches in a commercial building that is built over a crawlspace. The roaches are coming up from the crawlspace into work areas above. The crawlspace is inaccessible due to very low clearance. There are very few entry points, so we don’t know how to get insecticide into all the areas. The area is more than 100 feet long and more than 50 feet wide. What products and application methods would you suggest? J.S.

A: You probably can’t get dust to flow that far and, if the crawlspace is wet, most dusts will lose their effectiveness quickly. DeltaDust would be a good choice, though, if you can get the coverage.

An alternative is to use space treating equipment with enough energy to blow a liquid mist into all the areas. There are one or more pyrethroid insecticides with such application techniques on the label.

Finally, if you can’t reach all the areas, inspect the first floor for entry points for the roaches. These entries can either be sealed off or a bait dropped through them. Baygon bait has always been my choice for the “big” roaches. They forage strongly and when they find it, it kills them very quickly.

Special Aerosol Spray Works on Hornet Nest

Q: I have been using Ficam D dust for managing hornets in tree nests. Now I can’t get Ficam, so I’m looking for an alternative. Most labels I’ve read apply to indoor applications or treatments on houses-not in trees. What are your suggestions? F.K.

A: One solution would be to use one of the special aerosols designed for bees and wasps. Some of them work very well, and you can treat without wearing a bee suit or being stung. The other option is to wear a bee suit and simply put the nest into a plastic bag after removing it, and then treating the nest while it is inside the bag.


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