Fruit and leaf shoot of litchi （Litchi chinensis） infestation by naturally occurring populations of the fruit bprer, Conopomorpha sinensis larvae and C. sinensis parasitization rates were determined in litchi orchar...Fruit and leaf shoot of litchi （Litchi chinensis） infestation by naturally occurring populations of the fruit bprer, 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.展开更多
Conopomorpha sinensis is the dominant borer pest of Litchi chinensis(litchi)and Euphoria longan(longan)in China.Control of C.sinensis is difficult because of its cryptic life habit;thus,an effective ovicide could be b...Conopomorpha sinensis is the dominant borer pest of Litchi chinensis(litchi)and Euphoria longan(longan)in China.Control of C.sinensis is difficult because of its cryptic life habit;thus,an effective ovicide could be beneficial.The larvicidal effects of diflubenzuron(DFB)have been documented in many insect pest species.Therefore,DFB might be a useful ovicide to control C.sinensis.However,the detailed mode of action of DFB interference with insect molting and egg hatching is unclear.Thus,we studied alterations in expression of all genes potentially affected by DFB treatment using a transcriptome approach in 2-d-old C.sinensis eggs.Clean reads were assembled to generate 203455 unigenes and 440558 transcripts.A total of 4625 differently expressed genes,which included 2670 up-regulated and 1955 down-regulated unigenes,were identified.Chitin binding and chitin metabolic processes were among the most significant enriched pathways according to Gene Ontology analyses.Most of the genes that encode enzymes involved in the chitin biosynthesis pathway were unaffected,whereas genes that presumably encode cuticle proteins were up-regulated.Furthermore,altered expression patterns of 10 genes involved in the chitin biosynthesis pathway of C.sinensis embryos were observed in response to DFB treatment at different time points by quantitative reverse transcription polymerase chain reaction.We also observed abnormal development;there was reduced chitin content and modulated chitin distribution of newly hatched larvae,and altered egg hatching.Our findings illustrate an ovicidal effect of DFB on C.sinensis,and reveal more molecular consequences of DFB treatment on insects.展开更多
文摘Fruit and leaf shoot of litchi （Litchi chinensis） infestation by naturally occurring populations of the fruit bprer, 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.
基金This study received financial support from the National Natural Science Foundation of China(31801800)the Natural Science Foundation of Guangdong Province(2020A151501960)+1 种基金Special fund for scientific innovation strategy-construction of high level Academy of Agriculture Science(R2019PY-QY001)Research System Foundation of Litchi and Longan in China(CARS-32-12).
文摘Conopomorpha sinensis is the dominant borer pest of Litchi chinensis(litchi)and Euphoria longan(longan)in China.Control of C.sinensis is difficult because of its cryptic life habit;thus,an effective ovicide could be beneficial.The larvicidal effects of diflubenzuron(DFB)have been documented in many insect pest species.Therefore,DFB might be a useful ovicide to control C.sinensis.However,the detailed mode of action of DFB interference with insect molting and egg hatching is unclear.Thus,we studied alterations in expression of all genes potentially affected by DFB treatment using a transcriptome approach in 2-d-old C.sinensis eggs.Clean reads were assembled to generate 203455 unigenes and 440558 transcripts.A total of 4625 differently expressed genes,which included 2670 up-regulated and 1955 down-regulated unigenes,were identified.Chitin binding and chitin metabolic processes were among the most significant enriched pathways according to Gene Ontology analyses.Most of the genes that encode enzymes involved in the chitin biosynthesis pathway were unaffected,whereas genes that presumably encode cuticle proteins were up-regulated.Furthermore,altered expression patterns of 10 genes involved in the chitin biosynthesis pathway of C.sinensis embryos were observed in response to DFB treatment at different time points by quantitative reverse transcription polymerase chain reaction.We also observed abnormal development;there was reduced chitin content and modulated chitin distribution of newly hatched larvae,and altered egg hatching.Our findings illustrate an ovicidal effect of DFB on C.sinensis,and reveal more molecular consequences of DFB treatment on insects.
