Response of 'Royal Delicious' apple to the staggered pre-harvest fruit-bagging

Experiment was conducted to study the effect of staged fruit bagging on 'Royal Delicious' apples. For this, apples were bagged on three different dates, i.e., 60, 75 and 90 days after full bloom (DAFB). Observations were recorded on the incidence of insects, diseases and different quality attributes at harvest and during storage at ambient conditions (32 +/- 2 degrees C and 80 +/- 5% relative humidity). Our results revealed that the incidence of Sanjose scale insects (2.8 +/- 0.2 %), scab (4.2 +/- 0.2 %), sooty mold (0 +/- 0%) and fly speck (2.2 +/- 0.3%) was the least in apples bagged on 60 DAFB than those bagged on 75 DAFB or 90 DAFB or non-bagged apples. Apples bagged on an early date (60 DAFB) developed excellent colour (Hunter 'a' value = 62 +/- 2.1) than those bagged on later dates or those which were non-bagged (Hunter 'a' value = 36 +/- 1.2). Apples bagged on 60 DAFB were less firm, their total anthocyanin content were high (288.5 +/- 14.1 mg kg(-1) FW) than non-bagged apples (252 +/- 20.3 mg kg(-1) FW) but they exhibited high lipoxygenase (LOX) activity (0.462 +/- 0.03 Delta OD min(-1) g(-1) FW) than those bagged on 75 or 90 DAFB or non-bagged apples. The total phenolic contents (TPC) of 'Royal Delicious' apples were low (8.3 +/- 0.1 mg 100 g(-1) GAE) in apples bagged on 60 DAFB than non-bagged apples (9.5 +/- 0.2 mg 100 g(-1) GAE) but they exhibited quite high antioxidant (AOX) activity (12. 4 +/- 0.1 mu mol Trolox g(-1) FW) than apples bagged on later dates or non-bagged apples, which decreased substantially during storage. However, bagging date has no significant influence on eating quality attributes.