Comportamiento germinativo de semillas de Ipomoea nil (L.) Roth

<p>La especie <em>Ipomoea nil</em> (L.) Roth, conocida vulgarmente como “isipó”, “campanilla azul” o “bejuco” entre otros nombres, es de importancia en diversos cultivos del mundo en general y de la región nordeste argentino en particular. Su bioecología, forma de vida y las acciones antrópicas en el agroecosistema, hacen de ella una maleza muy difícil de manejar. Conocer su comportamiento germinativo ayudará a tomar medidas de manejo más eficientes. En el presente trabajo se muestran los porcentajes de germinación de esta especie considerando el tiempo transcurrido desde ser liberada hasta ser sembrada; también se analiza el escarificado mecánico (con lija), la inmersión en agua por 48 hs y un tratamiento combinado de escarificado mecánico con inmersión en agua por 48hs. Los resultados obtenidos ayudarían a comprender la alta presencia de esta especie en las áreas cultivadas.</p>

Ipomoea nil (white edge morning-glory).

Ipomoea nil is a climber species that has been widely cultivated as a garden ornamental across tropical, subtropical and warm temperate regions of the world. It is an aggressive and opportunistic colonizer producing stems that either twine into other plants for support or sprawl along the ground. It has escaped from cultivation and become widely naturalized and invasive, primarily in areas near cultivation, disturbed areas and forest edges. Currently, I. nil is listed as invasive in China, India, Philippines, Spain, Galapagos, Cuba, and on several islands in the Pacific Region.

Bruchine-Predated Seeds of Ipomoea nil (L.) Roth., A Cotton Crop Weed in Santiago Del Estero, Argentina

ABSTRACT: The insects of the family Bruchidae (Coleoptera) are important predators; their larvae feed upon and live in the seeds of a wide variety of plants. In Argentina, there not exists background information concerning the levels of predation of Ipomoea nil (Convolvulaceae) seeds caused by these insects. Thus, the aim of this work was to record the incidence of the species of the genus Megacerus as predators of I. nil seeds, an important weed affecting cotton growing in the irrigation area of Santiago del Estero. Megacerus maculiventris was the only bruchine species identified as predator of this weed. The predation percentage ranged from 0.84 to 15.66% in the agricultural years 2004-2008. It was attested that the number of predated seeds per capsule is independent from the number of seeds per fruit. However, it was proved that the insect predates just one seed per capsule and the highest predation frequency occurs in fruits containing more than three seeds. The levels of predation of I. nil by M. maculiventris are low in relation to those registered in other hosts by bruchines of the genus Megacerus.