Suitability of three different legumes for Acanthoscelides obtectus development and population growth

Abstract

Legumes are a rich source of valuable nutrients thus represent important component in human and animal nutrition. The most important and often a limiting factor in legume production is the presence of seed pests, such as the bean weevil Acanthoscelides obtectus (Say, 1831). This work tested the suitability of three different legume species (common bean, faba bean and grass pea), the species with a growing interest in the human diet, for the development of the bean weevil, aiming to provide a reliable forecast of its population growth. After four months, been weevils consumed the highest percentage of the common bean kernels (70.79%), followed by the grass pea (53.13%), and faba bean (0.42%). The progeny production and population growth were significantly affected by the tested legume species. After each month, the total number of adults was the highest on the common bean, indicating its best suitability for the weevil’s development. Based on the number of the emerged specimens after each month of the observation, the bean weevil development was unhampered and continuous also on the grass pea. The lowest number of emerged adults, in all observation periods, was in faba bean, indicating its low preference and suitability for the weevil’s development. The population growth of the bean weevil was the highest on the common bean, followed by grass pea, and it fitted best to the quadratic equation model that enabled the prediction of the population growth of the bean weevil for each legume species in the next generations.

Leguminoze su višestruko značajne, jer predstavljaju dragocen izvor različitih nutrijenata u ljudskoj i životinjskoj ishrani. Njihovim uzgojem doprinosi se raznolikosti agroekosistema i pozicioniraju se kao klimatski prilagodljiv usev. Najvažniji ograničavajući faktor u proizvodnji leguminoza predstavljaju štetotočine zrna (semena), poput pasuljevog žiška Acanthoscelides obtectus (Say, 1831). U ovom radu ispitana je pogodnost tri različite leguminoze (pasulj, sastrica i bob) sa rastućom popularnošću u ljudskoj ishrani, za razviće i rast populacije pasuljevog žiška. S ciljem utvrđivanja pouzdanog modela za prognozu populacijskog rasta štetočine, rezultati su korišćeni u matematičkom modelovanju. Istraživanja pokazuju da je, posle četiri meseca, zrno pasulja konzumirano u najvišem procentu (70,79%), manje sastrice (53,13%) i najmanje zrna boba (0,42%). Na produkciju potomstva i rast populacije statistički značajno je uticala vrsta leguminoze u ishrani. Ukupan broj eklodiralih imaga, na kraju svakog meseca u eksperimentalnom periodu, bio je najveći na pasulju, što pokazuje pogodnost ove biljke hraniteljke za razviće insekta. Eklozija imaga ukazuje da je razviće moguće i na sastrici. Najmanji broj imaga je eklodirao na zrnima boba, što ukazuje na nisku preferentnost i nepogodnost za razviće ovog insekta. Rast populacije žiška najintenzivniji je na pasulju, pa na sastrici, što je u potpunosti podržano kvadratnim regresionim modelom, koji omogućava prognozu rasta populacije pasuljevog žiška u svakoj narednoj generaciji.