DETERMINING THE APPROPRIATE TIME TO APPLY FRUIT FLY NETTING IN JUJUBE (Ziziphus mauritiana L.) PRODUCTION IN THE SOUTH CENTRAL REGION

Abstract

The study determined the appropriate time for covering fruit fly nets in jujube production in the South Central region, arranged in CRD blocks, with 4 formulas, 3 replications (corresponding to 3 locations). The research results showed that covering fruit fly nets affected microclimatic factors in jujube orchards, when covering nets reduced light intensity and temperature; but air humidity in apple orchards tended to increase. Covering nets affected the fruit set rate through flowering periods, especially covering nets from the beginning of the season affected the fruit set rate of the first flower (only 14.3%) and was lower than other formulas (17.0 - 17.3%). Covering nets helped to effectively manage fruit flies that harm jujube (through the rate of damaged fruit and larval density) both in the field and after harvesting and storage in the laboratory (netting formulas had a damage rate of less than 12% and larval density of less than 22.0 individuals/100 fruits, but the formula without netting had a damage rate of 75.0 - 81% and larval density of 504 - 619.3 individuals/100 fruits); the factors contributing to yield and actual jujube yield were significantly higher than the control without covering nets; the yield of the net covering formulas reached from 42.6 - 44.4 tons/ha; while the control only reached 14.1 tons/ha. At the same time, the use of fruit fly net covers also significantly improved the quality of jujube through Brix (%) and the rate of fruit flies after harvest (netting formulas had a rate of rotten fruit after 5 days of harvest of 12.5% ​​but the formula without net bags has a rate of rotten fruit after 5 days of harvest of 100%). In particular, the most suitable time for net covering for jujube trees in the South Central region is after the first fruit set (about 100 - 110 days after pruning), helping the jujube trees grow and develop stably (fruit set rate over 17%, actual yield of 44.4 tons/ha, Brix level of 11.0 - 11.6%) and fruit fly control is highly effective with a rate of damaged fruit of less than 2%.