This paper shows that Tenuipalpus pernicis is a dominant mite species on guava plants. A marked variation of population was observed throughout study period (from November, 2009 to October, 2011 (two consecutive years). It was found that The peak population was observed during June, in both the years, (27.50 ± 0.16 mites / 6.25 cm2, mean ± SD is calculated) when mean temperature, Relative humidity and rainfall were 30.01 ± 1.400C, 82.95 ± 2.45% and 0.35 ± 0.22 mm (mean ± SD) respectively. The population declined thereafter reaching the lowest in November in both the years (0.02 ± 0.07 mites / 6.25 cm2) when the mean temperature, relative humidity and rainfall were 26.31 ± 2.500C, 76.56 ± 4.72 %, and 0.81 ± 0.78 mm respectively. By following this population dynamics, cultivators can easily determine the proper time for mite control. It was also found that a significant depletion of important organic mineral and inorganic compounds occurred due to the infestation of this mite in the guava leaves. It was found that amount of chlorophyll, total protein, total carbohydrate, Mg, Zn, Cu , nitrate and nitrite were reduced by 2.79%,5.56%, 4.19%, 8.62%, 18.20%, 4.90%, 8.55%,16.78%, 10.35% respectively. It was also found that the amount of phenol increased slightly by 4.09% due to the infestation of this mite.