The effect of meteorological factors on the population build up of green leafhopperNephotettix virescens Dist (Cicadellidae, Hemiptera), plant hoppers Cofana spectra Dist (Delphacidae, Hemiptera) and C. yasumatsui Young (Kolla mimica, Hemiptera) and rice gundhi bug Leptocoriza acuta Thunberg (Alydidae, Hemiptera) in rice growing season (July to November) was studied through light trap collection during ten years (1988)(1989)(1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997). Maximum populations of Nephotettix virescens Dist (Cicadellidae, Hemiptera) and C. yasumatsui Young (Kolla mimica, Hemiptera) were recorded in the third week of October during all the years. Cofana spectra Dist had maintained peak activity in respect of population in the last week of September and third week of October. Leptocoriza acuta Thunberg (Alydidae, Hemiptera) had maximum population in second and third weeks of October during the aforesaid period. No meteorological factors have significant effect on the population build up of Nephotettix virescens Dist, Cofana spectra Dist and C. yasumatsui Young in the month of October. In the case of Leptocoriza acuta Thunberg, no other factor but rainfall had positive correlation of order 0.857 with population build up in the fourth week of September.

The present investigation was conducted at Experimental farm, ICAR-Central Institute for Arid Horticulture, Beechwal, Bikaner (Rajasthan), during the year 2016. The experiment was laid out in Randomized Block Design (RBD) having 15 treatments with three replications each. Foliar application of plant growth regulators and micro nutrients viz. NAA (20 & 40 ppm), 2,4-D (10 & 20 ppm), Zinc sulphate (0.5%), Borax (0.5%) alone and in combinations were applied twice in the month of April and May on 14 years old Kinnow trees. The initial vegetative growth of plant was recorded before imposing treatments in the month of April, 2016 and final at harvest in the month of December, 2016. Statistically, growth parameters increased maximum in terms of height and plant spread with treatment NAA 20 ppm + ZnSO4 0.5% as compared to control. Maximum zinc content (40.09ppm) was recorded in the leaves of Kinnow with foliar spray of NAA 20 ppm + ZnSO4 0.5% while maximum boron content (41.52 ppm) was recorded with foliar spray 2,4-D 10 ppm + Borax 0.5% as compared to control.