Author(s): P. K. SARKAR, G. P.TIMSINA , P. RAI AND S. CHAKRABARTI

Abstract: Chilli thrips (Scirtothrips dorsalis Hood), aphids (Aphis gossypii Glover), broad mite (Polyphagotarsonemus latus Banks) and fruit borer ( Heliothes armigera Hubner) are major sucking and chewing pests of chilli in Indian sub-continent inflicting yield loss up to 75% or more. Now-a-days, IPM has been attaining immense importance in the agricultural scenario of India and abroad. Hence formulation of a sustainable IPM module was felt necessary under West Bengal, like other crops in India, where vegetable cultivation is done mostly by the small and marginal farmers. Different IPM modules were attempted of which , module: I (M-I) comprised of organics and safer insecticide and was found to be the most effective module against sucking pest complex (aphids, thrips, mites) vis-a-vis chilli fruit borer, and the prevailing natural enemies (Amblyseius ovalis., Spiders, Chielomenes sexmacculata, Coccinella septempunctata and Stethorus gilvifrons) in chilli eco-system were moderately safe (average 8.45% mortality) . Yield of green chilli was higher (5.13 q-1ha) in M-I (marigold trap crop, vermicompost 2.5 tha-1 + neem cake 250 kg-1ha (devoid of recommended dose of fertilizers, i.e RDF) superimposed with sequential application of insecticides like neemazal TS @ 2 ml l-1 (5 WAT), diafenthiuron @ 1g/l (8 WAT), flubendiamide @ 0.2 ml l-1 (11 WAT) and neemazal T.S.@ 2.5 ml l-1 at 14 WAT) followed by M II (5.04 ha-1) (marigold trap crop+ neemcake 500 kg-1ha + vermicompost 1.25 t ha-1 + without RDF) superimposed with sprays of NSKE @ 5%(5 WAT), abamectin @ 0.75 ml l-1 (8 WAT), spinosyn @ 0.3 ml l-1 (11 WAT) and NPV @250 LE per hectare (14 WAT) and M III (neemcake 125 kg-1ha + vermicompost 625 kg-1ha at transplanting (TP) and at 50 DAT (50% N and 100% PK) superimposed with sprays of nimbecidine @ 5 ml l-1 (2 WAT), NSKE @ 5% (5 WAT), nimbicidine @ 5 ml l-1 (7 WAT), NSKE @ 5% (11WAT) . In M III, the natural enemies were totally undisturbed even their population was found to be increased in time hours. Further, highest B:C (benefit:cost) ratio was recorded in M-III followed by M-IV: (cent per cent RDF+ recommended plant protection (RPP) followed by application two rounds of emamectin benzoate (@ 0.3 ml/l) (2WAT) and propargite (2.5 ml/l) (5 WAT) + carbaryl (4 g l-1) (7, 11 WAT) + M-I. Hence, M-III in comparison with M-I and M-II seemed to be a quite promising strategy (yield of green chilli:4.91ha-1) as it did not require any insecticidal interference keeping natural enemy eco-system undisturbed.

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