Effect of internal insect infestation on single kernel mass and particle density of corn and wheat

Authors: BOAC, JOSEPHINE - Kansas Department Of Health And Environment; Casada, Mark; Pordesimo, Lester; ARTHUR, FRANKLIN - Retired ARS Employee; MAGHIRANG, RONALDO - University Of Illinois; MINA, C. - Central Bank Of The Philippines

Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2022
Publication Date: 6/10/2022
Citation: Boac, J., Casada, M.E., Pordesimo, L.O., Arthur, F.H., Maghirang, R., Mina, C.D. 2022. Effect of internal insect infestation on single kernel mass and particle density of corn and wheat. Applied Engineering in Agriculture. 38(3):583-588. https://doi.org/10.13031/aea.14858.
DOI: https://doi.org/10.13031/aea.14858

Interpretive Summary: To model the dynamics of insect infestation in a grain handling system using computer simulations, such as the discrete element method (DEM), physical properties of grain kernels infested by internally feeding insects compared to their sound counterparts are needed. Specifically, particle density and single kernel mass of infested kernels are data inputs required for the simulations. Thus, we measured the particle density and single kernel mass of internally infested kernels as affected by insect age for corn and wheat, infested with rice weevil and lesser grain borer, respectively. Measurements were obtained when infesting insects were at approximately 14, 28, 35, and 42 days of age after developing into young larvae, old larvae, pupae, and pre-merged adults, respectively. The measured kernel physical properties were not affected by the number of internal insects per kernel. In both corn and wheat, single kernel mass decreased after the larval stage of the internally feeding insects. Single kernel mass decreased from 374 mg in sound corn to 346 mg in corn with pre-emerged adults and from 31.4 mg in sound wheat to 25.9 mg in wheat with pre-emerged adults. Particle density increased with insect age for both rice weevils in corn and lesser grain borer in wheat with a linear trend. Data obtained from this study enables effective DEM modeling of commingling of insect-infested and sound grain kernels in grain handling systems. Knowledge about the spread of insect infestation from known insect pest reservoirs: elevator boots and pit areas, can be used to improve the effectiveness and efficiency of the insect pest management program of any commercial grain elevator or other grain handlers and processors.

Technical Abstract: To model the dynamics of insect infestation in a grain handling system using the discrete element method (DEM), physical properties of the infested kernels compared to their sound counterparts are needed, specifically particle density and single kernel mass of infested kernels. Thus, the objective of this study was to determine the particle density and single kernel mass of internally infested kernels as affected by insect age. Corn and wheat were infested with internal feeders: rice weevil (Sitophilus oryzae (L.)) in corn and lesser grain borer (Rhyzopertha dominica (F.)) in wheat. The internal feeders were allowed to grow and mature inside the kernels and properties were measured for representative samples selected using X-ray imaging approximately 14, 28, 35, and 42 days after the end of a 4-day oviposition period. The measured kernel physical properties were not affected by the number of internal insects per kernel. In both corn and wheat, single kernel mass decreased after the larval stage of the internally feeding insects. Single kernel mass decreased from 374 mg in the sound corn to 346 mg in corn with pre-emerged adults and from 31.4 mg in sound wheat to 25.9 mg in wheat with pre-emerged adults. Particle density increased with insect age for both rice weevils in corn and lesser grain borer in wheat with a linear trend. The increasing particle density while the kernel mass is being eroded indicates that kernel internal void is being detected by the gas pycnometer employed for measurement of the true volume of grain kernels. Data obtained from this study enables effective DEM modeling of grain commingling of insect-infested and sound grain kernels in grain handling systems.