Fig 1.
Data logger as seen before sealing of the PICS bag.
Wireless data loggers were used to measure temperature and relative humidity conditions within PICS bags. Data loggers were pushed into the center of the maize bulk prior to sealing the bags.
Fig 2.
Temperature and Relative Humidity (RH) readings from two study locations.
Temperature readings in both study locations (A, B) (see Methods and Materials) ranged between 20 and 30°C. Temperatures varied by about 14 degrees in the first location, while the second location’s temperature varied by about 4 degrees. Temperatures within the treatment bags correlated closely with environmental temperature. The R.H. of both rooms (C, D) were similar over the 8 month period. The R.H. in woven bags correlated with the environmental R.H. The R.H. within triple bags, however, did not change with environmental humidity and remained within a narrow range for the duration of the trial.
Table 1.
Results of Pearson’s correlation comparing treatment bag temperature to room temperature.
Table 2.
Results of Pearson’s correlation comparing bag relative humidity to room RH.
Fig 3.
Oxygen levels observed in sealed triple bags and unsealed woven bags over an eight month period.
Oxygen levels in infested triple bags (black circles) declined rapidly during the first month of the study period. Opening the bags allowed for fresh oxygen to enter and raise the overall percent oxygen, but these values remained lower than the levels recorded for the non-infested triple bags (white circles), infested woven bags (black diamond), and non-infested woven bags (white diamond) and would gradually decline as surviving insects continued to deplete the oxygen inside.
Fig 4.
Grain moisture in sealed triple bags and unsealed woven bags over eight months.
Both triple bag treatments remained relatively stable during the eight month study period, staying approximately between 12 and 13%. Grain moisture declined in both woven bag treatment groups, with the infested group losing 5.1% and the non-infested bags losing an average of 5.8% moisture content.
Table 3.
Results of ANOVA analyses comparing the treatment effect on grain moisture.
Fig 5.
Relative damage observed in stored maize over eight months.
Damage to the maize varied from month to month. Recorded levels of grain damage were highly variable from one time point to the next. Only the woven, infested group (light gray, stripes) had a consistent increase in grain damage over the course of 8 months.
Table 4.
Results of ANOVA analyses comparing treatment effect of relative damage to maize grain.
Fig 6.
Maize germination rate after eight months of storage.
There was no significant effect of storage treatment on germination during the first 6 months of the trial. After 8 months of storage, grain stored in infested woven bags had significantly lower germination rates than those stored in triple bags and non-infested woven bags.