No abstract

Measurements of soil heat flux were made over bare black cotton soil at Pune in the period June 1976 to February 1977, using a soil heat flux plate. Hourly values of soil heat flux from 00 to 24 LAT are presented for selected days typical of the monsoon, post-monsoon and winter seasons. The diurnal variation is generally characterised by a cross-over from negative to positive values at 07 hr, occurrence of maximum around noon and return to negative values between 16 and 18 hr. The effects of rainfall, cloudiness and soil moisture on the soil heat flux are discussed.

Paddy stem-borer (Tryporyza Incertulas Walker) infestation is very much influenced by meteorological factors. The effect of various weather elements on its incidence is endeavoured in present statistical analysis. It is found that less moisture content in the atmosphere in the elongation stage and a minimum temperature lower than 23 deg. C and sunshine hours more than 8 hours in flowering stage are favourable for increased larval activity in the earing stage of summer paddy crop at Bhubaneshwar. Northeast region of India are prone to heavy attack in summer and winter crops earing stage. Similar studies for other stations are necessary to draw general conclusion about threshold values of meteorological parameters to be used in forewarning of the infestation of stem-borer in paddy.

The dependence of stemborer incidences on sugarcane crop upon the meteorological factors is well recognized. Therefore to explore the feasibility of meteorological forewarning of its attack, the statistical analysis of entomological and meteorological data for the years 1967-1980 from Anakapalle has been done and discussed in this paper. The simple and multiple linear regression techniques were used. An attempt is also made to delineate the approximate risky zone for stemborer attacks in India on the basis of qualitative pest data for the years 1954-1980 received from nearly 50 agrometeorological stations in India.