Gilbert® Lamp Replacement Recommendations

It is not necessary to replace attractant lamps each year
in most circumstances. 

Only For Optimum Performance Should You
"Replace insect attractant lamps once each year, in the spring."

Lamp Replacement Recommendations
By David Gilbert

The recommendation to "replace insect attractant lamps each year, annually in spring", originated with phone calls from customers (food plants and pharmaceutical laboratories) who said their traps were not working as well as they did last year, when they were new. Don Gilbert, knew lamps deteriorate over time (see graphs below). So, in response he began to recommend annual lamp replacement to insure traps were operating at their best during the summer insect season.

Don's customers in the 1960s, while he was pioneering the industrial use of ILTs (Insect Light Traps), were primarily supermarkets, food plants, and pharmaceutical laboratories. These customers were highly concerned with controlling flying insects in their facilities, excited to have these new tools to help them, and did not want their new found ability to control flying insects to deteriorate from one year to the next. Annual spring replacement would insure their traps were operating at peak efficiency during the insect season. This recommendation became more and more accepted as years passed. For the last couple of decades, it has become quoted as some sort of absolute truth, but it is and always was a recommendation for peak performance of traps. Some facilities may get by with replacing lamps every two years in spring, maybe even three years?

Perhaps attractant lamps might be replaced less often in facilities where there are relatively few flies to worry about or where controlling them is not of upmost concern. However, pharmaceutical laboratories (famous for establishing peak performing pest management programs), our nation's food plants, and hospitals will need to see well documented evidence before cutting back on their uncomprising efforts to keep the bugs out of our food, drugs, and operating rooms. There has been no published research for peer review or to gain a better understanding of when to replace lamps for different types of facilities. For years, we have been recommending further research and establishment of ILTs as a science. And, that for the pest management industry to pursue true professionalism in this field, it will be necessary that legitimate, verifiable research be published, open to scientific review, debated, and constantly improved.

Further Research

The November 1, 2013 "Entomology Today" reported that the NPMA (National Pest Management Association) has recently sponsored research into this very topic at the University of Florida with a $10,000 grant. Kudos! Perhaps, finally, we are on our way!

The researchers, an entomology professor in University of Florida's Institute of Food and Agricultural Sciences and a doctoral student at UF, owner of a pest management company. The Professor presented study findings at Pest World 2013. Great, we need good research diseminated to people who can put it into practice. On the other hand, it was presented before publishing the research, without peer review.

The researchers reportedly found that 13-month old "bulbs" caught 80 to 90 percent as many flies as the new "bulbs" caught. The professor seems to believe that this shows attractant lamps don't need to be replaced annually, but does it? What does 80 to 90 percent as many flies really mean? Without knowing the methods or materials used in the study, whether the researchers had enough experience in ILT research to control variables, if their conclusions are well considered or properly worded, we are left in the dark.

A peer reviewed research paper would mean something. It would give the industry a starting point, a place to begin the scientific debate, a beginning, not an end.

Don Gilbert's 1967 recommendation to replace lamps annually in spring will remain as THE recommendation for optimal performance of UV flourescent lamps. In areas of the world where there is no winter, some facilities replace lamps twice a year. Further research might help determine which type facilities can get by with a lower performance from their ILTs.

I am hoping that this effort will support ILTs as science and not just another marketing gimmick, another manufacturer misleading PhDs and PCOs into insincere research to back their marketing gimmicks: "Our lamps are so good, you only have to replace them every two or three years!" Yes, you can do that with any brand lamps, but if you are going to make claims, let's see the research published and peer reviewed. And, please, include this peer reviewer (before you start the research, if possible).

*According to the manufacturer, the average output of Sylvania® attractant lamps** (when matched with the proper ballast) will decrease from 100% to 80% in the first 100 hours (4 days), to 72% in 500 hours (20 days), to 68% in 1000 hours (41 days), and to 60% in 2000 hours (83 days). The deterioration continues at a decreasing rate, approximately 3% a month. 15 watt lamps will deteriorate faster than 20 watt lamps and 20 watt lamps a little faster than 40 watt. See graphs (below). I mentioned “proper ballast” because at least one ILT manufacturer overdrives its lamps with two ballasts, increasing its effectiveness for about a week, but significantly increasing the deterioration rate, quickly reducing effectiveness. You can't compare deterioration rates of different brand lamps using manufacturer's graphs. You have to do tests with real insects. About all these graphs do is show that lamps do deteriorate over time.

F40/350BL/ECO Lamp

F20T12/350BL/ECO Lamp

F15T12/350BL/ECO Lamp

**  The insect attractant lamp  specified is the Osram/Sylvania® 350BL/ECO Phosphor Lamp (as manufactured in North America).

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