Bionomics of the grape flea beetle Scelodonta strigicollis (Motschulsky) (Coleoptera: Chrysomelidae).
Kulkarni K. A.
Author Affiliation: Agricultural College, Dharwar, Karnataka, India.
Mysore Journal of Agricultural Sciences 5 : 308-316
Abstract : The biology of the Eumolpid Scelodonta strigicollis (Motsch.), a pest of grape vines in India [cf. RAE/A 44, p. 425, etc.], was investigated in the laboratory and field at Dharwar, Karnataka, in 1968-69. In the field, adults and larvae were found only on vines, but in the laboratory the adults fed also on mango and Erythrina indica. Adults on grape vine fed on tender buds and leaves (on which they made holes) and tendrils, stems and unripe berries (which they damaged by scraping). In the field, adults were more numerous in October-November (8-10/vine) than in April-May (4-6/vine). The larvae fed on the roots, especially of cuttings in their first year, devouring the cortical layer and causing the leaves to turn yellow and drop off, with the result that some young vines were killed. Adults spread by flying, and immature stages were spread as eggs and larvae on cuttings. The eggs were laid singly or in groups of 15-50 beneath loose bark. In the laboratory at 23.3-29.5 deg C, the duration of the egg and larval stages averaged 5.6 and 37.6 days, respectively, and the prepupal, pupal, preoviposition, oviposition and postoviposition periods lasted 2-3 and 7-11 days and 1, 2.5-3.5 and 4-4.5 months, respectively. Pupation took place in an earthen cell at a depth of 2.5-3 in. in the soil. Adults mated 25-35 days after emergence, and 250-325 eggs/female were laid in 14-15 batches. In the field, beetles were found and oviposition took place throughout the year.