Submitted to: Experimental and Applied Acarology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2017
Publication Date: 2/14/2018
Citation: Martin, D.E., Latheef, M.A. 2018. Active optical sensor assessment of spider mite damage on greenhouse beans and cotton. Experimental and Applied Acarology. 74(2):147-158.
Interpretive Summary: Two spotted spider mites cause extensive damage to cotton in the U.S. resulting in yield losses and fiber degradation. In this study, cotton and pinto beans were infested with different numbers of spider mites and during the following 27 days the resulting damage to plant health was quantified using an active optical sensor. The optical sensor was able to measure spider mite damage to both cotton and beans and separate out differences. This work established that cotton is much more susceptible to spider mite damage than beans. Researchers will be able to use this information to help them grow and maintain better spider mite colonies for research in the laboratory using pinto beans as superior host plants.
Technical Abstract: The two-spotted spider mite, Tetranychus urticae Koch is an important pest of cotton in mid-southern United States and causes yield reduction, and deprivation in fiber fitness. A greenhouse colony of the spider mite was used to infest cotton and pinto beans at the three-leaf and trifoliate stages, respectively. The plant vigor of each plant was studied daily for 27 days using a multispectral optical sensor. Spider mite damage on cotton and bean canopy was determined using the Normalized Difference Vegetation Index (NDVI) indicating changes in the spectral reflectance of the plant canopy. Sustained loss of plant vigor occurred in both cotton and beans treated with spider mites compared to untreated control plants. Plant health decreased incrementally on treated cotton until day 21 when complete destruction of the plant occurred. Thereafter, regrowth reversed decline in plant health. On spider mite treated beans, plant vigor plateaued until day 11 when plant health declined incrementally. Overall, the reduction in plant health was significantly more declivous for cotton than for beans. Data also demonstrated that pinto beans were better suited as a host plant than cotton for rearing T. urticae in the laboratory.