Determination of optimum spraying time for chemical control of mulberry scale, Pseudaulacaspis pentagona (Targioni) (Hemiptera : diaspididae) in tea fields

Monitoring methods of mulberry scale larvae, Pseudaulacaspis pentagona, wer e evaluated for determining the spraying time for effective chemical contro l. Among them, the calculation of the ratio of "more than half hatched egg batches" which was found to be suitable due to its accuracy, is, however, t ime-consuming. Optimum spraying time is defined as the duration of the peri od required to achieve a ratio of more than half hatched eggs in egg batche s (60 to 90%), which is referred to as"more than half hatched egg batches." The use of sticky traps set inside a tea bush to capture crawlers of the m ulberry scale is a simple and accurate monitoring method. The optimum spray ing time occurs 2 to 5 days after the peak capture of the crawlers by the t raps. The traps should be set up from the beginning of the egg hatching per iod, and should be examined daily or every other day to determine the peak capture of the crawlers. The use of sticky traps for monitoring is suitable for only the first generation of mulberry scale. Thus observations of "mor e than half hatched egg batches" are needed to determine the optimum sprayi ng time for the second and third generations of the mulberry scale.