Chitin Biosynthesis Inhibitors in Euschistus heros Fabr. (Hemiptera: Pentatomidae): Morphometric Alterations in Testes and Nuclei of Testicular Accessory Cells of Adults

Euschistus heros is an important pest in Brazilian agriculture growing importance in the general Neotropical realm. Its reproductive potential is the key factor for its characterization as a pest in major crops such as soybean and cotton. The aims of this study were to characterize morphometric parameters of testicles and testicular accessory cells-TACs nuclei of adults E. heros treated with chitin biosynthesis inhibitors (CBIs). The insecticides lufenuron (Match® 50 EC) and buprofezin (Applaud® 250 WP) were applied individually in 4th instar nymphs, remained in controlled conditions until the emergence of adult males. The testicles were identified and removed 72 h after emergency, fixed, photographed for anatomic analysis, and processed for morphometric analyses of the TACs nuclei. It was possible to observe that lufenuron and buprofezin decreased the testicular area. Buprofezin decreased the mean nuclear area analyzed in the TACs, and nuclear hypertrophy can indicate an activity on support and nutrition of germ line cells, presenting a possible effect on protein synthesis. The intense reaction for Fast green in control compared to buprofezin treatment may indicate that total protein (histones and non-histones) has been altered. The tested insecticides, with special focus on buprofezin may affect the final stages of reproductive development of E. heros, with potential to be used in field to the control of this pest.