The rhinoceros beetles Oryctes elegans Prell and Oryctes agamemnon Burmeister are palms pests. This study was conducted to determine the economic injury level (EIL) of these pests. The statistical design was randomized complete block with 5 treatments and 3 replications More
The rhinoceros beetles Oryctes elegans Prell and Oryctes agamemnon Burmeister are palms pests. This study was conducted to determine the economic injury level (EIL) of these pests. The statistical design was randomized complete block with 5 treatments and 3 replications. Four concentrations including 0.5, 1, 1.5 and 2 ml/liter DOR 200 SL (Imidacloprid) were injected in palm trunks. Sampling was performed monthly. The date palm yields were recorded at harvest. The relationship between injury and yield reduction was used to estimate damage. The (EIL) was calculated by using Norton method. The regression relation was calculated between the damage and the yield loss rate. The costs of cultural control were calculated based on three different height of trees. Product prices were also subdivided by the prices of first, second and third-degree dates to determine the different economic levels loss for each product quality. Based on the results, the lowest EIL was calculated for the combination of cultural for shorter date palms and chemical control and the first-degree dates that it was 1.5 holes at the base of the petiole per tree. Due to the higher cost of biological control, EIL was higher for the combination of biological and cultural control. This value was 0.5 holes per second in short palm trees. The EIL increased with increasing palm height as well as decreasing crop prices. The highest EIL was calculated for the combination of biological and cultural controls at dates grade 2.
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