Population Density of Radish Beetle Colaphellus apcalis (Menetries) and its Control with Insecticides

The radish beetle Colaphellus apcalis (Menetries) is a highly dangerous insect to economically important crops. This study was conducted at the Agricultural Research Station of the College of Agriculture, University of Basrah, in 2024 to evaluate the density of the radish beetle on mustard (Brassica napus), Canola (Brassica nigra), and radish (Raphanus sativus), and to control it using sticky traps and four insecticides. The results showed that infestation rates were 73.33, 73.33, and 53.33% on canola, radish, and mustard, respectively. The traps also played an effective role in reducing the insect population density. The highest number of trapped insects reached 52.003, 42.33, and 27.11 insects/ trap of mustard, canola, and radish, respectively. The results also showed a negative correlation between temperature and insect density, with a correlation coefficient of r = - 0.93, while a positive correlation was found between relative humidity and insect density, with a correlation coefficient of r = 1. The insecticides used in the study Babil (alpha cypermethrin), Liberty (deltamethrin), dimethoate, and ventab (thiamethoxam + lambda cyhalothrin) achieved high efficacy with high adult mortality (99.78, 99.11, 99.37, and 100%), respectively.