LED grow lights alter sorghum growth and sugarcane aphid (Hemiptera: Aphididae) plant interactions in a controlled environment

Authors: LIMAJE, ANKUR - Oklahoma State University; Armstrong, John; PAUDYAL, SULOCHANA - Oklahoma State University; HOBACK, WYATT - Oklahoma State University

Submitted to: Florida Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/26/2018
Publication Date: 4/11/2019
Citation: Limaje, A., Armstrong, J.S., Paudyal, S., Hoback, W. 2019. LED grow lights alter sorghum growth and sugarcane aphid (Hemiptera: Aphididae) plant interactions in a controlled environment. Florida Entomologist. 102(1):174-180. https://doi.org/10.1653/024.102.0128.
DOI: https://doi.org/10.1653/024.102.0128

Interpretive Summary: We studied the effects of LED lights on sorghum plant morphology, nutrient uptake, and pathogen development and sugarcane / sorghum interaction when compared to plants are grown under the conventional lighting inside identical growth chambers. LED lights resulted in deleterious sorghum growth with fewer true leaves formed, reduced plant height, lower chlorophyll content, and an unusual pink to purple coloration of the plant tissue when compared to sorghum grown under conventional lighting. All four of the different sorghums grown under LED had 2x the amount of biomass measured as dry weights for upper (stems and leaves) and lower (root mass) when compared to the conventional lighting. When sorghums were infested with sugarcane aphid, Melanaphis sacchari (Zehntner), both light sources supported similar numbers of aphids, but plants grown under LED had higher damage ratings than those under conventional lights for both know resistant and susceptible sorghums. For future trials, sorghum should not be grown using the LED lights when assessing host-plant resistance to aphid infestation.

Technical Abstract: Normal growth and production of plant tissues requires water, carbon dioxide, nutrients and light. Light emitting diodes (LED) are increasingly being used as a substitute for florescent or incandescent light sources in greenhouse horticulture because of their small size, durability, wavelength specificity, long operating life, and efficiency in offering photosynthetically active radiation at lowered energy costs compared to conventional lights. However, studies conducted to test the effects of these lights reveal that spectral properties of LED can have dramatic effects on plant morphology, nutrient uptake, and pathogen development when plants are grown under the incorrect light spectrums. We grew sorghum plants under a LED grow panel, and compared it to plants grown under conventional florescent lighting within identical environmental chambers. LED lighting resulted in deleterious sorghum growth with fewer true leaves formed, reduced plant height, lower chlorophyll content, and an unusual pink to purple coloration of the plant tissue when compared to sorghum grown under conventional lighting. All four of the different sorghums grown under LED had 2x the amount of biomass measured as dry weights for upper (stems and leaves) and lower (root mass) when compared to the conventional lighting. When sorghums were infested with sugarcane aphid, Melanaphis sacchari (Zehntner), both light sources supported similar numbers of aphids, but plants grown under LED had higher damage ratings than those under conventional lights for both know resistant and susceptible sorghums. For future trials, sorghum should not be grown using the LED lights when assessing host-plant resistance to aphid infestation.