A simple mass rearing method for dipha aphidivora, the pyralid predator of sugarcane woolly aphid ceratovacuna lanigera

Abstract

A simple laboratory method for mass rearingDipha aphidivora (Meyrick) (Lepidoptera: Pyralidae), a predominant predator of sugarcane woolly aphid (SWA)Ceratovacuna lanigera Zehntner (Homoptera: Aphididae), was developed as an alternative to rearing in shade net houses. The predator was reared on field-collected SWA infested sugarcane leaf bits in GI trays of 60 cm x 45 cm x 10 cm size. Of the several problems faced in the rearing, two major ones required solutions to make the methodology a success: (i) extensive dispersal of aphids from the rearing trays and (ii) the labour intensive process of collectingDipha larvae from drying old leaf bits and inoculating them on fresh bits at every change. The first problem was solved by stacking one tier of uninfested leaf bits above every tier of infested leaf bits and at right angle to the lower layer. The second problem of manual collectionof Dipha larvae was overcome by stacking new leaf bit sets contiguous to the old ones which facilitated the predator larvae to disperse from drying old leaf bit sets to the new ones on their own. Sets comprising 50 infested and 50 uninfested leaf bits stacked in four tiers and inoculated with 500 eggs ofD. aphidivora followed by provisioning of the same numbers of leaf bits in the same fashion six times at 3 day intervals, gave 78.5% pupal recovery at the end of the rearing period of 18 days. Protocols for producing 35,000 cocoons ofD. aphidivora in single cycle or staggered modes are outlined.