Determining the composition of fruit flies damage to jackfruit and effect of some plant extracts to prevent fruit fly egg laying was carried out from January to November 2022 at Southern Horticultural Research Institute (SOFRI) and the jackfruit farms at Tan Lap and Tan Thanh communes, Tan Thanh district, Long An province. The results of determining the composition of "Changai" jackfruit fruit fly species in 15 orchards revealed that there were two fruit fly species, Bactrocera dorsalis and B. umbrosa with a frequency of occurrence of 80.0% and 26.67%, respectively. The lab trial to study efficiency of five plant extracts Allium sativum (Garlic), Allium cepa (Onion), Wedelia trilobata (Wedelia), Artemisia absinthium (Mugwort), Azadirachta indica (Neem) to prevent egg laying of B. dorsalis was conducted; the results showed that two treatments of plant extracts A. indica and W. trilobata were highly effective against B. dorsalis with rates of 82.22% and 71.50% at 7 days after treatment. In laboratory conditions, 0.9% concentration neem seed extract was effective in preventing fruit fly oviposition on jackfruit fruits by 83.19%. In field conditions, the results of spraying neem seed extracts at a concentration of 0.9% with 8 times/fruit crop and 6 times/fruit crop (5 and 7 days/time, respectively) reduced the damage of fruit flies with the damage rate of 41.67% and 50.33%, respectively. The experimental results have an initial significance in contributing to the integrated pest management process of fruit fly damage on jackfruit.

Study on natural enemy composition and effectiveness to control pupae and adult of Oriental fruit fly (Bactrocera dorsalis) damage on star apple using entomopathogenic fungi conducted from August 2020 to August 2021 at Southern Horticultural Research Institute and star apple orchards in Chau Thanh district, Tien Giang province. The results research on natural enemy composition of fruit flies at 10 star apple orchards recorded that there were nine natural enemy species such as Paecilomyces lilacinus, bigheaded ant (Pheidole megacephala), fire ant (Solenopsis invicta), and parasitoid wasp (Diachasmimorpha longicaudata) appeared commonly with the frequency of 32.20%, 37.14%, 39.28%, and 48.00%, respectively. Followed by black earwig (Chelisoches morio), jumping spider (Plexippus paykulli), Metarhizium sp. and weaver ant (Oecophylla smaragdina) occurred less commonly with a frequency of 7.86%, 12.86%, 15.40%, and 20.00%, respectively. Beauveria sp. was very rarely with a frequency of 3.40%. Experimentally evaluating the ability to control B. dorsalis pupae and adults by entomopathogenic fungi indicated that P. lilacinus, Metarhizium sp., and TKS -BTMET (Metarhizium sp. + Beauveria sp. + Paecilomyces sp.) product were equally effective to control fruit fly adults with effectiveness of 79.12%, 69.22%, and 66.30%, respectively.

The study investigated the damage situation of fruit borers on longan in Dong Thap, Tien Giang, and Vinh Long provinces and evaluated the effect of different fruit bagging materials on preventing harmful fruit borers and fruit quality of longan cv. Edor during 2019-2020. The experiment arranged in a randomized complete block design (RCBD) four replications and five treatments. The treatments were non-woven bag, Bikoo micro-hole bag, Agro-net bag (49 holes.cm-2 ), white cotton bag, and control (uncovered fruits). The investigation indicated that fruit borers appeared and caused damage fruit from 2 weeks after fruit set to harvesting time. The percentage of infected fruit of longan orchards were high at 4 weeks after fruit set (1.75%) in Dong Thap, and in Tien Giang, Vinh Long provinces at 10 weeks after fruit set (1.46% and 2.04%, respectively). During 12 weeks from fruit bagging to harvest, bagging of fruits by four types of material did not damaged by fruit borers. However, control treatment increased the rate of infected fruits continuously (7.22% at harvest time). Agro-net bag (49 holes.cm -2 ), Bikoo microhole bags, and white cotton bag were low fruit drop rate (30.73%, 30.65%, and 32.11%) when compared to control (47.14%). From the results obtained conclusion that application of fruit bags on longan cv. Edor was highly effective in preventing damage from fruit borers and ultimately production free from pesticides residues.

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