The paper shows that a significant depletion of important organic, mineral and inorganic compounds occurred due the infestation of Oligonychus mangiferus in the leaves of Mango. Among the organic compounds, chlorophyll, total protein, phenol and total carbohydrate were selected for the study. Among minerals, Magnesium (Mg), Zinc (Zn), Copper (Cu) and Iron (Fe) were selected and among the inorganic materials, nitrate and nitrite were selected for the study. It was found that amount of chlorophyll, total protein, total carbohydrate, Mg, Zn, Cu, Fe, nitrate and nitrite were reduced by 15.36%, 19.08%, 17.54%, 11.93%, 23.15%, 32.32%, 16.20%, 20.19% and 23.23% respectively. It was also found that the amount of phenol increased by 21.21% due to mite feeding.

A good number of plant mites are injurious pests of agricultural and horticultural crops causing considerable yield loss. Aceria mangiferi (bud mite) reduces the yield in mango by 50-80%; Polyphagotarsomenus latus, reduces the yield by 27-39% in mango; Aceria cajani reduces the yield by 15-30% in red gram; Oligonychus caffeae reduces the yield by 5-11% in tea; spider mites reduce the yield by 10-15% in veges; Aceria litchi reduces the yield by 30% in litchi; Oligonychus oryzae reduces by 20-25% in paddy; Oligonychus indicus reduces by 20-30% in sugar cane; spider mites reduce the yield by 13-30% in brinjal and 23-25% in lady's finger (Gupta, 2003). Since very little is known about the changes in the biochemical components of mango leaves due to mite infestation, a study was undertaken to assess the same.

The collection of infested and uninfested mango leaves was done particularly from Namkhana and Nimpith [24-Parganas (S)] areas. The entire work was carried out during the pre-monsoon period (March to June) as a considerable number of this mites were found during this season.

Some mango plants were selected for the collection of uninfested leaves. Prior to the collection of uninfested leaves, the plant was sprayed with a very mild dose of insecticide to avoid mite and other insect infestation. For biochemical analysis, heavily infested leaves, as well as uninfested healthy leaves of mango were collected.

The estimation of chlorophyll was done following the method of Arnon (1949). Total carbohydrate was estimated following the method of Hedge et al. (1962). Phenol was estimated following the method of Spies (1955). Nitrate and nitrite, were estimated following Strickland and Parsons (1965). Before the analysis, fresh uninfected leaves were collected to serve as control and were processed separately for analysis.

For quantitative estimation of minerals like Magnesium (Mg), Copper (Cu), Zinc (Zn) and Iron (Fe), the methodologies and kits supplied by Merk, Germany, were followed using a preprogrammed spectrophotometer (SQ-118).

Environmental Sciences Journal, Biochemical Changes of Mango Leaves, Oligonychus Mangiferus, Polyphagotarsomenus Latus, Agricultural Crops, Horticultural Crops, Organic Compounds, Tetranychus Ludeni, Dolichotetranychus Floridanus, Eotetranychus Suginamensis, Phenolic Compounds, Nitrite Compounds, Preprogrammed Spectrophotometer, Biochemical Analysis.