Author(s): V. VISALAKSHMI, P. RAMA MOHANA RAO AND N. HARI SATYANARAYANA

Abstract: Field experiments were conducted during rabi 2008-09 and 2009-10 at Agricultural Research Station, Ragolu, Srikakulam district in Andhra Pradesh to assess the comparative incidence of insect pests in two different systems of rice cultivation i.e., System of Rice Intensification (SRI) and in conventional transplanting method. Incidence of yellow stem borer (Scirpophaga incertulas (Walker)) was recorded at tillering stage and at reproductive stage whereas, incidence of gallmidge (Orseolia oryzae (Wood Mason)) was recorded only at tillering stage. Stem borer incidence was low in SRI method (6.1% dead hearts and 7.2% white ears) compared to conventional method of cultivation (15.6% DH and 11.9% WE). The same trend continued in case of gall midge too with 4.1% silver shoots in SRI method against 7.1% in conventional method. In the conventional transplanting method gallmidge incidence was low in MTU1010 (6.4%) where as stem borer incidence at vegetative (15.1%) and reproductive stage (11.1) was low in hybrid. Yield increase to the tune of 1.3% and 11.88% were recorded in SRI over conventional transplanting method during rabi 2008 and 2009 respectively in hybrid Arize 6444 and MTU1010 variety. Yield increase in case of SRI method was more in MTU1010 during rabi 2008 (11.73%) where as it was more in hybrid during rabi 2009 (17.3%). Highest cost benefit ratio was observed in SRI method with hybrid Arize 6444 during 2008 (1:1.70) and 2009 (1:1.72).

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