Life Tables of Sugar-Cane Top Borer, Scirpophaga Excerptalis Wlk.

Abstract

Key mortality factors of sugar-cane top borer, Scirpophaga excerptalis Wlk. during the third brood were quantified on a susceptible sugar-cane variety, Co 1148 during 1981 and on susceptible CoJ 64, resistant CoJ 67 and collateral hosts, Sorghum halepense Peru, and Saccharum spontaneum L., during 1982 in Haryana (sub-tropical India). As artificial rearing of this borer is not possible, a methodology to have uniform age group at the beginning of the study by tagging the egg masses and the freshly attacked plants was developed. Results showed that parasitization of various stages and failure of neonate larvae to enter the midribs were the key mortality factors common to all the hosts. In 5. halepense there was negative trend index (0.104) due to high mortality of larvae in all the instars. This revealed that it is not a suitable host for top borer. No predators were found to feed on any of the sub-imaginal stages of the borer due to the unique habits of the borer.

Résumé

Les clef mortalité facteur de tête boreur de canne a sucre durant de in re broche wast apprête en variété Co 1148 dans 1981 at pour susceptible CoJ 64, resistant CoJ 67 et collateral hote Sorghum halepense et Saccharum spontaneum en 1983 dans l’état d’Hariana (Inde). Comme artificiet élever a cet égard le boreur ill ne’n le possible, a méthode a la uniforme sucle a’ la commencement a etude etie employe par etiquette d’oeufs anas et nouvelle agress plant. Les résultats de parasitisme du varie stade larvaire et failure de entre de neo larvae dans nervus mediane worst d’clef mortalie facteurs common a aile hote. La negative direction indice dans 5. halepense a cause de elive mortalité d’iarvae en aile stade re vêler et worst ne gut hote. Ne predators worst fund se noueru du subimaginai stade de le boreur a cause de une unique mancere de la boreur.