SHARMA, P LCHOUDHARY, KHUSHI RAM2019-01-112019-01-112018-11http://krishikosh.egranth.ac.in/handle/1/5810090043ABSTRACT Tuta absoluta (Meyrick) is one of the most destructive pests of tomato throughout the world. Present study deals with the spatial distribution and sequential sampling plan for this pest and the associated predatory bug, Nesidiocoris tenuis (Reuter). The pest and the predator existed throughout the growing season both in open fields and polyhouse with larval density varying from 1.01 to 5.44 under open fields and 0.57 to 10.71 under polyhouse conditions, respectively. In both the situations the pest as well as the predator followed aggregated distribution and the data fitted well the Taylor’s power law and Iwao patchiness regression. Within plant T. absoluta larvae were distributed on all the three plant strata with slight preference to the middle stratum (open field: 33.5-46.8%; polyhouse: 30.3-43.2%) than the bottom (open field: 22-36.4%; polyhouse: 28.8-36.9%) or the top (open field: 21.7-36.2%; polyhouse: 21.8 to 34.4%). Mine count was reliably used to estimate larval density and to predict the possible fruit damage on week later. The optimum sample size decreased with the increase in density and decrease in precision and vice-versa. Control decision lines for T. absoluta were developed on the basis of larval and mine density separately for open field and polyhouse conditions in the presence and absence of N. tenuis. The maximum numbers of sampling units in case of sequential sampling were less as compared to stratified random sampling and the presence of the predator pushed the decision lines up in each case. Present study provides useful information for effective monitoring and taking suitable pest management decision for the pest.ennullThesis