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duration cultivars are invariably intercropped with cereals such as sorghum [Sorghum bicolor (L.) Moench], Maruca vitrata (Geyer) is a serious insect pest of tropical legumes. pearl millet [Pennisetum glaucum (L.) R.Br.], and maize In Sri Lanka, yield losses due to Maruca damage in pigeonpea [Cajanus cajan (L.) Millsp.] range up to 100%. The development of resistant [Zea mays (L.)]. The short-duration (100-120 d) types, cultivars and germplasm is one of the best means of control. The generally grown as a sole crop in crop rotation with objectives of this study were to screen 271 accessions for resistance wheat (Triticum aestivum L.), are of recent origin, and to M. vitrata and evaluate reaction of lines selected from the promising play a major role in increasing cropping intensity and accessions. The high level of natural incidence of Maruca in Sri Lanka adoption of pigeonpea across a wider range of latitudes. provided an opportunity for evaluation of germplasm at Field Crops This development has resulted in the emergence of new Research and Development Institute, Maha Illuppallama. Screening cropping systems in the subtropical environments (Saxof the germplasm accessions revealed large variation in Maruca damena, 2000). These types, when sown at the on-set of the age to flowers and pods. On average, the Maruca damage in determirainy season (October-March) in Sri Lanka, commence nate accessions (66-75%) was higher than that of nondeterminate flowering in the middle or towards the end of the rainy accessions (41-50%). Resistant plants from four determinate and 12 nondeterminate accessions were selected.

Maruca vitrata (Geyer) is a serious insect pest of tropical legumes. In Sri Lanka, yield losses due to Maruca damage in pigeonpea [Cajanus cajan (L.) Millsp.] range up to 100%. The development of resistant cultivars and germplasm is one of the best means of control. The objectives of this study were to screen 271 accessions for resistance to M. vitrata and evaluate reaction of lines selected from the promising accessions. The high level of natural incidence of Maruca in Sri Lanka provided an opportunity for evaluation of germplasm at Field Crops Research and Development Institute, Maha Illuppallama. Screening of the germplasm accessions revealed large variation in Maruca damage to flowers and pods. On average, the Maruca damage in determinate accessions (66–75%) was higher than that of nondeterminate accessions (41–50%). Resistant plants from four determinate and 12 nondeterminate accessions were selected. Further selection for resistance to Maruca damage among and within lines derived from the resistant plants was exercised for six generations under nonsprayed field conditions. Under insecticide‐free conditions, the selections from two accessions showed significant yield advantages over controls. Data on pod damage and larval counts indicated that the resistance was conditioned through yield compensation mechanisms. In pigeonpea, this is the first report of the selection of Maruca resistant lines. Further studies showed that by using the resistant genotypes it is possible to reduce the number of insecticide sprays for economic yields.

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