Biology and control of the fruit borer, Conopomorpha sinensis Bradley on litchi (Litchi chinensis Sonn.) in northern Thailand

Abstract

Fruit and leaf shoot of litchi (Litchi chinensis) infestation by naturally occurring populations of the fruit borer, Conopomorpha sinensis larvae and C. sinensis parasitization rates were determined in litchi orchards in northern Thailand at high (ca. 1 400 m ASL) and low (ca. 800 m ASL) elevations with different, non-overlapping fruiting seasons. In addition, spray applications of Bacillus thuringiensis var. aizawai, the natural compound spinosad and the chemical pesticide imidacloprid were conducted in the field to test the effects of these agents on C. sinensis fruit infestation rate. Fruit infestation rate and fruit growth, studied in a low elevation orchard, were sigmoidal and showed a highly significant positive correlation (P ≤ 0.01). Leaf shoot infestation rate in the low elevation orchard decreased in the course of the fruiting season (March until May), but increased in the high elevation orchard, where no fruits were present within the same period of time. Together, these results indicate that females of C. sinensis clearly prefer fruits over shoots for oviposition. If no fruits are available, which was the case in the high elevation orchard during that time, they are constrained to lay their eggs on shoots. The parasitization rate of C. sinensis larvae in untreated fruits was 54.3%. The parasitoid species were Chelonus chailini (90.8%) and Phanerotoma sp. (9.2%). In the leaf shoots, C. sinensis was found to be parasitized by Phanerotoma sp. and Apanteles briareus. The applications of the different active agents had no significant effect on C. sinensis fruit infestation compared to the untreated control. Besides the cryptic life of the larvae, this is most probably explained by the fact that C. sinensis has several generations during the fruiting season. Because of the high parasitization rates recorded, an alternative and more effective control measure than the application of pesticides might be the augmentative release of parasitoids.

Development and Behavioral Ecology of Conopomorpha cramerella (Lepidoptera: Gracillariidae)

“…J.F.Gmel. ; Sapindaceae) in China (Schulte et al 2007;Li et al 2013;Meng et al 2014;Fu et al 2016;Zhang et al 2016). Our observations described here bring new ecological knowledge, providing new perspectives on potential IPM methods for pest C. cramerella populations.…”

From Challenges to Sustainable Solutions for Upland Agriculture in Southeast Asia

“…Bruijnzeel 2004). Litchi has been the focus of a number of case studies aimed at testing improved management tools such as water saving irrigation methods (Spreer et al 2007;Pinmanee et al 2011), biological pest control (Schulte et al 2007), vegetation studies (Euler et al 2006), plant hormonal processes (Hegele et al 2010), fruit drying Janjai et al 2011) and post-harvest methods (Reichel et al in press). Other case study crops have included longan and mango, with the research on longan focusing on the identification of those plant hormones that induce flowering (e.g., Bangerth et al 2010;Tiyayon et al 2011), and the research on mango focusing on irrigation methods in Thailand (e.g., Spreer et al 2009) and fruit set in Vietnam (Römer et al 2011).…”

Evaluation of Insecticides for the Management of Litchi Fruit and Shoot Borer

“…Among insect-pests, litchi fruit and shoot borer, Conopomorpha sinensis (Lepidoptera: Gracillariidae) is one of the major threats to litchi growers, causing severe losses to fruit as well as young shoots causing up to 24-48% and 7-70%, respectively , Li et al 2014. Conopomorpha sinensis adult female lays eggs on leaves, shoot, or fruits stems singly or in groups and after hatched larvae penetrate the fruits, flower, tender shoots and leaves, and feed on seed neck immediately which causes poor fruit quality and fruits drop after infestation (Waite 2005, Schulte 2007, Huang et al 1994, Manzel 2002, Tsang and Liang 2007, Kumar et al 2014, Meng et al 2018. Conopomorpha sinensis attacks litchi and Longan (Dimocarpus longan Lour.)…”