UV lights

Richard Worth rworth at oda.state.or.us
Thu Jun 28 12:57:15 EDT 2001


Have there been tests done on the effectiveness of different tubes 
when combined with different white sheet configuations?  I'm thinking 
primarily of the increased effectiveness of using a parabolic sheet 
set-up as I saw discussed in the Masters thesis of Noel McFarland, 
OSU, 1963.   The idea, as I understand it, is to keep the moths 
around for a longer period without the use of a trap.


>In a message dated Wed, 27 Jun 2001 10:28:46 PM Eastern Daylight 
>Time, "JH" <jhimmel at CONNIX.COM> writes:
>Hi folks - A friend mentioned to me that he has   been seeing very 
>few moths at his lights in northern Pennsylvania. He read   on the 
>package of his UV bulb (one of those semi-circular tubes) that they 
>loose   their effectiveness after a while. He was wondering, half 
>seriously, if   this was just to get people to by more bulbs. Has 
>anyone heard of this   happening? 
>John   Himmelman
>Killingworth, CT USA
>jhimmel at connix.com
>John:I have been designing, building, and marketing Light Traps for 
>over 22 years. More importantly, I use the traps that I make as a 
>Lepidopterists. As a result, I have researched the fluorescent light 
>bulb with some GE engineers at their Neala Park Research Facility a 
>number of years ago. Here are some of the things I learned.
>Fluorescent tubes were originally design straight. The 
>&#8220;shaped&#8221; fluorescent tubes were originally design for 
>home/household lighting as a space saving, energy efficient and 
>effective source of light. When UV Black Lights were developed, the 
>pest control industry requested a shaped UV tube for their products. 
>Bug Zappers and Insect Collection Traps for pest control is a huge 
>market for the light bulb manufacturing industry.
>The effectiveness of bug zappers is an ongoing debate. There have 
>been numerous studies and papers, which indicate the ineffectiveness 
>of bug zappers, especially on the target insect, Mosquitoes. In 
>1999, over 6 million bug zapping devices were sold in North America. 
>Virtually all use shaped fluorescent tubes.
>The straight tube emits 99% of the light away from the bulb. Shaped 
>tubes emit 20% of more of the light back towards some part of the 
>tube. The &#8220;blue&#8221; bands in UV light are easily distorted. 
>Once the light is distorted, it is virtually lost. I visited the GE 
>Research Facility in 1985. An engineer tested a straight tube and a 
>&#8220;U&#8221; shaped tube. The straight tube emitted a wider and 
>longer light pattern. The &#8220;U&#8221; shaped tube emitted a 
>smaller and extremely compact light pattern with considerable 
>distortion. Also, as the shape tube ages with use, more and more of 
>the light pattern becomes distorted which reduces effectiveness by 
>38% after 900 hours of use. This can vary greatly from tube to tube 
>and manufacture to manufacture. The straight tube is also effected 
>by use by 1% or less.
>The diameter of the tube also effects the amount of emitted light. 
>The reach or the distance the effective UV light travels is 
>extremely important in the design of the light traps. Agri-light 
>Products produced a 15 Watt light trap for use in buildings housing 
>live stock to collect flies and other pest insects that were 
>attracted by the livestock. Bug zappers then replaced Argri-light 
>traps as a matter of convenience as the Agri-light required 
>servicing to remove the flies that were collected and killed. Bug 
>zappers require no servicing. The bug zapper was more convenient and 
>for a period of time it was widely believed that the flies were no 
>longer attracted to the zappers. The &#8220;U&#8221; shape tubes in 
>bug zappers distorted the light and had a serious impact on the 
>effectiveness of the UV light and the performance of the device. 
>Other chemical type products have since been developed and have 
>replaced most bug zappers.
>I originally began with 8 Watt straight tubes, my current standard 
>light trap is a 15 Watt straight tube. I also produce a 20 Watt 
>straight tube. Neither the 8 Watt nor the 15 Watt can match the 
>effectiveness of the 20 Watt.
>Sylvania LTD of UK recently introduce the Quantum tube for use in 
>the pest control industry. It has been advertised to be 40% more 
>effective than the UV tubes currently available.  I am currently 
>field testing two 15 Watt Quantum bulbs. The current results 
>indicate that they have a greater reach. I intend to visit a lab in 
>Pittsburgh, PA late this fall and have them perform a UV light test.
>It is very difficult to determine moth populations with the use of a 
>single light or type of light. Especially in urban areas where 
>reflected light has a huge impact UV lights. Reflected light from 
>urban areas as well as moon light greatly reduce the reach of UV 
>light. Moon light can make manmade UV light useless.
>It is my considered opinion that straight tubes are much more 
>effective than shaped tubes.
>Leroy C. Koehn
>202 Redding Road
>Georgetown, KY 40324
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Richard A. Worth
Oregon Department of Agriculture
Plant Division
rworth at oda.state.or.us
(503) 986-6461


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