Tea Quarterly 

Abstract: It was evident that the urease activity of soils varies with location, depth, season and forms of nitrogen fertilizer used. The long-term use of copper fungicide for blister blight control did not significantly alter the soil urease activity, although in laboratory experiments copper inhibited urease activity at levels above 100 ppm. Soil fumigation with methyl bromide destroyed up to 60% of the urease activity, but at two weeks from fumigation recovery has apparently started.

Abstract: SUMMARY Outbreaks of the red spider mite (Oligonychus coffeae Nietn.), the purple mite (Calacarus carinatus Green) and the scarlet mite (Brevipalpus californicus Banks) of tea were closely associated with the monthly rainfall pattern. Peak numbers occurred during the intermonsoonal dry periods. The relationship between mite numbers and the rainfall pattern suggests that control measures should commence at the end of the first month after the dry season begins. More red spider mites, but fewer purple mites, occurred on tea grown under shaded conditions. Observations on the relationship between scarlet mite numbers and shade were inconclusive. It is suggested that, in addition to direct effects of rainfall and shade, mite numbers are determined by certain biochemical processes that take place within the tea leaves.