Pest Management Professional, May 2018

Tales from the field Flat roofs have been at the root of several problem accounts Ive serviced over the years Here are just a few examples Pharmaceutical fungus beetles I encountered a fungus beetle problem in a sterile production area of a pharmaceutical plant Sticky monitors above the drop ceiling confirmed the roof was the source This is where customer interviews are important I learned that the roof had been replaced several months prior Why I asked Because the roof was leaking I was told For 75000 they had the roof replaced An inspection I recommended found that the roofer had placed the new membrane directly over the old including over accumulations of leaves and other organic materials Keep in mind one of the protocols for replacing a membrane roof includes removing all organic materials before putting down the new membrane The roofer was brought in and he admitted he had not followed protocol so he had to replace the roof again at his cost and after removing the organic materials The problem was resolved It is always heart stopping when such a recommendation is made and the roof is actually opened usually before an audience Fungus gnats at a school A school with a flat roof had a fungus gnat problem The roof had plywood placed atop steel gridwork with insulation above the plywood Moisture readings found the wood to be wet in many areas moisture reading above 14 percent Schools never seem to have enough money for such repairs so rather than replacing the entire roof the maintenance team took moisture readings throughout When they encountered higher than normal levels they cored the plywood and sent it out for examination If fungus gnat larvae were found that section was removed and replaced Finally a new membrane was installed over the entire roof area and the problem was solved Fungus gnats at a restaurant Some years ago a pest management professional PMP asked me to inspect a private dining room in a restaurant It had a fungus gnat problem That area also had a flat roof After inspecting above the drop ceiling I recommended they replace the roof I also recommended that they remove all wet materials found when the roof was opened The recommendation was in writing which the PMP presented to the restaurant owner The PMP also paid me Several weeks later he called to tell me that the roof was fixed but the problem was still present He wanted a free inspection I made a deal The inspection would be free if another moisture source was found I suggested he make sure that all wet materials had been removed during the roof renovation if they were not I would charge for the reinspection He called back several days later to inform me that upon further investigation he had learned that the restaurant had simply patched the roof They had neither opened it nor had they removed any wet materials The PMP saved himself some dollars and also solved the problem after the roof was opened and repaired properly Photo Wikimedia Commons JezebelithaCa mypmp net Pest Management Professional May 2018 47 The bottom line is that all wet materials must be removed to solve the problem Just patching the roof will not D M pipes that penetrate the roof and concrete if present Generally speaking insects breeding in the roof will enter around the vent pipes Fungus gnats will hover around the opening around the vent pipe Fungus beetles often can be found around ceiling lights Psocids will be difficult to see Sometimes you cant locate the pests but a temporary insect light trap ILT and or sticky trap will If you find pests above the drop ceiling you need to have the roof opened for inspection This is the most difficult part of dealing with the customer The customer doesnt want to spend the money when you cant guarantee the roof is the problem Have the roof opened around vent pipes as you can often see the insects traveling to the vent pipe area Then follow the moisture to the actual source If the roof Isnt leakIng Erythraeid mite infestations stem from roof moisture problems but not necessarily because the roof is leaking These mites are predacious on small insects such as springtails Many flat roofs are not perfectly flat and rainwater collects in some areas During rainy periods the water in these little ponds never dries out Springtail populations begin If the moisture problem persists long enough erythaeid mites appear These mites can be found crawling on the roof on the upper exterior walls of the building and around upper floor windows Erythraeid mite problems are often misdiagnosed as clover mite problems because both mites are red Dont be fooled If you have a red mite problem on the upper floors of a flat roofed building you likely have an erythraeid mite infestation Removing low spots on the roof usually is not practical Rather an appropriate insecticidal spray on the roof will eliminate both the springtail problem and the mite problem Beyond the roof Not all moisture loving insects are related to roof problems It is not uncommon to find psocids fungus gnats and fungus beetles in new construction but not coming from the roof New construction usually has a lot of moisture in it Framing wood studs etc often contain as much as 19 percent moisture although it will continue to lose moisture as it ages in place However consider wood that is stacked at a building site for extended periods and is rained on repeatedly It too will contain higher than usual