Insect Pests and Natural Enemies in Moroccan Sugar Beet Cultivation

This study, conducted in the Zemamra locality, Morocco, over three seasons (2020/2021, 2021/2022, 2022/2023), investigates the population fluctuations of the main insects of sugar beet plants and their associated natural enemies. The results showed that sugar beet plants harbored 18 insect pests and 18 natural enemies. Cassida vittata Villers, a prominent pest, showed fluctuations from 13.3% to 13.6%. The primary predator, Hippodamia convergens Guérin-Méneville, decreased from 18.4% to 15.7%. Parasitoids Monorthochaeta nigra Blood & Kryger and Aprostocetus sp. displayed notable population changes. Pest populations peaked during week 17 of each year (April 25, 2021; April 24, 2022; and April 30, 2023), with natural enemies mirroring these peaks. Diversity indices for insect pests showcased stable species richness (S = 17.6) but significant abundance fluctuations: 326.2 (2020-2021), 370.2 (2021-2022), and 348.9 (2022-2023). Other indices (Dominance_D, Simpson_1-D, Shannon_H, Evenness_e^H/S, Brillouin, Menhinick, Margalef, Equitability_J, Fisher_alpha, Berger-Parker, Chao-1) did not significantly differ (P > 0.05). Diversity indices for natural enemies exhibited increased species richness (S: 16.7 to 17.6) and abundance (N: 71.1 to 154.2). Significant variations were observed in Brillouin, Menhinick, and Margalef indices. Correlation matrices unveiled intricate relationships among diversity indices for insect pests and natural enemies. Dissimilarity analyses indicated substantial seasonal differences. High dissimilarity is noted between 2020-2021 and both 2021-2022 and 2022-2023 (P = 0.0001). Significant dissimilarities among insect pests and natural enemies highlight the dynamic nature of these communities across seasons. This study contributes crucial insights for adaptive pest management practices, emphasizing the need for further research to refine strategies based on these interactions.