Abstract

Groundnut (Arachis hypogaea Linn.) is one of the main cash crops of Madras State grown over an area of about 20,66,000 acres. The major insect pest of the crop is the redhairy caterpillar, Amsacta albistriga M. (Arctiidae- Lepidoptera) and its occurrence is more or less an annual feature in most of the red sandy loam tracts of the South. The pest is polyphagons but it is parti- cularly destructive to groundnut. The incidence of the pest varies from tract to tract as it is influenced to a large extent by the local rainfall and agricultural practices. According to the peculiarities in the seasonal and climatic conditions, the areas chronically infested by the pest has been broadly classified into three zones viz., (1) South Arcot, North Arcot and Salem (June-October), (ii) Madurai and Ramanathapuram (August-October) and (iii) Pollachi (Coimbatore District) (May-June) by Nagarajan and Ramachandran (1958). In Madurai region with the receipt of showers the sowing of the dry crops are extended up to August- September. Concomitant with this the emergence of the moths takes place and the pest assumes alarming proportions by August-October. By dusting BHC 10% within a week after the emergence of the moth, the pest can be annihilated completely, provided the control measures are taken by the ryots on a co- operative basis. The grown up caterpillars can be controlled by dusting Toxaphene 20% or by spraying parathion (Nagarajan et al. 1957; Nagarajan and Ramachandran 1958).

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