Dennis Shuman

Acoustic location fixing insect detector

A device and a method for locating and counting insects in agricultural commodities has been developed. Acoustic sensors pick up sounds emanating from adult and or larval insects. The electrical outputs of the sensors are amplified and analyzed to determine (1) the first sensor to detect the sound, (2) the second sensor to detect the sound and (3) the time difference between the first and second detection. These determinations are used to calculate the locations and numbers of insects in the agricultural commodity samples.

Electronic and manual monitoring of Cryptolestes ferrugineus (Coleoptera: Laemophloeidae) in stored wheat

Trapping studies were conducted with field populations of Cryptolestes ferrugineus in small steel bins filled with stored wheat. Traps tested in a comparison experiment included two types of commercially available probe-pitfall trap and the trapping body of the electronic grain probe insect counter (EGPIC) system. Quantities of insects captured were compared among the three traps. Insect captures in PC pitfall traps, whether at the grain surface or 17 cm below the surface, exceeded those found in WB II probe and EGPIC probe bodies. The number of adult C. ferrugineus captured was similar between the EGPIC probe bodies and WB II probe traps. With probes positioned near the grain surface, insect counts generated by the EGPIC system were analyzed for changes in rate of capture after inserting the probe, changes within a single 24-h period, and variation with temperature. EGPIC counts varied from 0.5 counts per hour to 5.9 counts per hour throughout the study. Cryptolestes ferrugineus counts increased with increasing daily mean air temperature and decreased when air temperature decreased. There was a consistent increase in the rate of counts during the early evening hours. Increased activity of C. ferrugineus in the early evening hours may have been due to insect response to higher air temperatures near the grain surface late in the day, although grain temperature near the trap varied little throughout the day. Alternatively, diel periodicity in C. ferrugineus may be due to an independent circadian rhythm as evidenced in other grain insects. Variation in counts among days after the probe was inserted was not consistent.

Laboratory evaluation of an improved electronic grain probe insect counter

An Electronic Grain Probe Insect Counter system, which incorporates modified passive grain probes, allows offsite monitoring and detection of insect pests in stored grain. An electronic count is generated whenever an insect falls through an infrared beam in the sensor head located at the bottom of the electronic grain probe. We report descriptions and laboratory evaluations of prototype electronic grain probes that were custom-made in-house (n=8) and by small-scale manufacturing (n=54). Laboratory tests, in which dead insects were dropped through a probe, were conducted to determine if electronic probes accurately count the numbers of insects that are captured. Accuracy of the manufactured electronic probes increased as the size of the test insect increased from 93.6% for the smallest insect tested (Cryptolestes ferrugineus, the rusty grain beetle) to 99.5% for the largest (Tribolium castaneum, the red flour beetle). Custom-made probes were significantly more accurate for C. ferrugineus (96.5% versus 93.6%) but there was no difference in accuracies for the larger insects. Comparisons among all probes found that probe accuracy was correlated with variation in the magnitude of the output signal from the infrared phototransistor. Thus, use of diode/phototransistor pairs with a more consistent beam or with improved beam focus may further improve probe accuracy. Good performance was obtained with the manufactured electronic probes. Tests with live insects under field conditions are needed to further evaluate the system performance.