Management of Gram Caterpillar, Helicoverpa armigera (Hubner) with Bt Formulation in Chickpea under Organic Conditions

Abstract

Background: Chickpea is an important pulse crop and grown widely in the world. Similar to other crops it is vulnerable to a broad range of insect-pests. Mainly, the gram pod borer, Helicoverpa armigera severe pest being that causes huge losses to chickpea crop. Farmers generally rely on chemical measures for its management that leads to various problems viz. resistance development, pest resurgence and residue problem along with environmental degradation. Methods: During 2018-19 and 2019-20 microbial pesticide viz. Bacillus thuringiensis var. kurstaki 0.5 WP (DOR Bt 1) was tested @ 1.5, 1.75 and 2.0 kg/ha for the management of gram caterpillar, Helicoverpa armigera in chickpea at Organic Research Farm, Punjab Agricultural University (PAU), Ludhiana. The application of spray was carried out, first at pod initiation and second 15 days thereafter. The observations were recorded on the larval population per meter plant row after 7 and 15 days of spray. The pod damage was recorded at the time of harvest wherein random samples of 200 pods per plot per replication were collected to observe the number of damaged pods. Result: On overall mean basis at 15 DAS, the lowest larval population was observed in DOR Bt-1 @ 2.0 kg/ha (1.19 larvae/ 5 plants) followed by 1.75 kg/ha (1.54 larvae/ metre plant row) and 1.5 kg/ha (1.79 larvae/metre plant row) as against highest larval count in untreated control (3.20/metre plant row) on chickpea. The DOR Bt-1 @ 2.0 kg/ha performed better due to highest pest reduction (62.81%) than its lower dosages DOR Bt-1 @ 1.75 kg/ha (51.88%) and DOR Bt-1 @ 1.5 kg/ha (44.06%) at 15 DAS. Also, DOR Bt-1 @ 2.0 kg/ha recorded highest pod damage reduction (76.14%) over its lower dosages, i.e., DOR Bt-1 @ 1.75 kg/ha (54.18%) and DOR Bt-1 @ 1.5 kg/ha (38.24%). DOR Bt-1 @ 2.00 kg/ha (1275 kg/ha) was better due to highest yield compared to its lower dosages and the untreated control, where there was lower yield.