Evolution has equipped many insects with a sublime ability to camouflage themselves.  |
Pest Insects may remain hidden under most light wavelengths as shown here on a greenhouse lemon balm plant. |
Insects may stay hidden under daylight wavelengths too. |
Evolution has equipped many insects with effective camouflage appearances |
Interestingly and importantly for the grower, ultraviolet lights used at night that produce illumination in the wave range between 300nm and 400 nm can often illuminate otherwise camouflaged pest insects.
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UVb light can assist in identifying the presence of crop pests |
Pest reconnaissance of crops in cultivation areas including those in row plantings and in the greenhouses can be conducted at night often with successful results for insect identification efforts.
Insects, plant damage, and even chlorophyll containing algae and cyanobacteria can be identified at night by examining plant stems, leaves and flowers using UVa and UVb lights. Many insects react to UV light through florescence of phosphors in their exoskeletons. Chlorophyll on the other hand under UVb absorbs all light waves except for 'red' wavelengths which are reflected back. Algae growing across cultivation areas can easily be identified using UVb light.
Not all insects that glow under UV light are considered pests. Potentially beneficial organisms such as stick insects, millipedes and even anoles can be easily spotted using UVa and UVb flashlights.
My personal favorite light for night insect surveillance are lithium rechargable, well built LED units with UVb filters.
Though the grower may not spot all pest insects on their greenhouse or row crop plants, chances are any key pest infestation can be quickly identified.