Morris has used light-trap catches of carpenter-worm moths on which to base the 

 timing of trunk spray applications for the control of carpenter-worms in hardwoods in 

 Mississippi. 



A study of the published data indicates the possibility of associating light-trap data 

 with field infestations for predicting the need of control measures for the folio-wing in- 

 sects: European corn borer, corn earworm, cotton bollworm, tomato fruitworm, 

 mosquitoes, sand flies, codling moths, bud moth and leaf roller in apples, Asiatic garden 

 beetle, white grubs, pink bollworm, armyworms, cutworms, cabbage loopers, and leaf- 

 hoppers. 



There are three more or less essential requirements that must be met before the 

 use of light traps to predict the need for control can be successful. 



1. There must be either an economically damaging infestation or a potentially 

 damaging infestation of the insect or insects present in the locality. 



2. The adults of the species involved must be nocturnal, positively phototropic 

 insects. 



3. There must be some knowledge of the biology of the species and a specific 

 knowledge of the relationship between the light-trap catch and the field infesta- 

 tion. 



At the present time the limitation on this use for light traps is number 3, particularly 

 the lack of information on the correlation of light-trap catches and the field infestations. 



Whether the light trap can be used as a direct survey tool or only as an indirect tool, 

 supplementing other survey methods, will depend to a large extent on the insect and/or 

 host involved. 



The light-trap catch may indicate the presence of an insect in a given area in 

 potentially damaging numbers, but the determination of the need for control measures in 

 any given field in most instances still must be subject to a manual survey of that field 

 for one or more of a number of reasons: 



1. The crop in the field may not be attractive for oviposition. 



2. Predators and parasites may prevent the infestation from ever developing. 



3. Disease may -wipe out the infestation before control measures are justified. 



4. Climatic conditions may prevent the infestation from developing. 



5. Host preference may cause the insect to go to another crop in the area. 



6. Infestation may be spotted and not occur in all fields. 



7. Chemical control measures in use in the field for another insect pest may keep 

 down the infestation. 



One advantage light traps have over more conventional survey methods is that one 

 light trap properly located can furnish information on a number of economic species 

 attacking a variety of crops, -without having to go into the different fields to check for 

 each insect. By using the light trap in this manner and by going into the specific crop to 

 look for a specific insect pest only when the light trap catch has indicated the need to do 

 so, a considerable saving in time and money can be effected over the present manual 

 survey methods. 



To summarize - -some usage is already being made of light traps to predict the need 

 for control. At present this use is rather limited. It is my belief that in the future the 

 greatest field of usefulness for light traps will be as a survey tool- -either as a direct 

 method to predict the need for control, or as an indirect method, utilizing light-trap data 

 to determine -where specific manual surveys are needed. 



The greatest need is for more investigations on the relationships between light- 

 trap catches and field populations and the factors affecting this relationship. Research 



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