Development of a Postharvest Cold Treatment for Cryptophlebia peltastica (Lepidoptera: Tortricidae) for Export of Litchis From South Africa
- Moore, Sean D, Kirkman, Wayne, Peyper, Mellissa, Thackeray, Sean R, Marsberg, Tamryn, Albertyn, Sonnica, Hill, Martin P
- Authors: Moore, Sean D , Kirkman, Wayne , Peyper, Mellissa , Thackeray, Sean R , Marsberg, Tamryn , Albertyn, Sonnica , Hill, Martin P
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423729 , vital:72089 , xlink:href="https://doi.org/10.1093/jee/toy287"
- Description: The litchi moth, Cryptophlebia peltastica (Meyrick) (Lepidoptera: Tortricidae), is endemic to sub-Saharan Africa and certain Indian Ocean islands. It is an important pest of litchis and to a lesser extent macadamias. Litchis are exported to certain markets that consider C. peltastica as a phytosanitary pest. Consequently, an effective postharvest phytosanitary treatment is required. This study sought to develop a cold disinfestation treatment for this purpose. First, it was established that the fifth instar was the most cold-tolerant larval stage, as it was the only instar for which there was still some survival after 12 d at 1°C. It was then determined that cold treatment trials could be conducted in artificial diet, as there was no survival of fifth instar C. peltastica in litchis after only 9 d at 1°C, whereas it took 15 d at this temperature before no survival of fifth instar C. peltastica was recorded in artificial diet. Consequently, cold susceptibility of fifth instar C. peltastica and the most cold-tolerant larval stages (fourth and fifth instar) of false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), were compared in artificial diet. There was no survival of C. peltastica after 13 d at 1°C, whereas this was only so for T. leucotreta after 16 d. Consequently, it can be concluded that any cold treatment that has been proven effective against T. leucotreta would be as effective against C. peltastica. Finally, it was confirmed that the cold susceptibility of T. leucotreta in artificial diet did not overestimate the effect of cold on T. leucotreta larvae in litchis.
- Full Text:
- Date Issued: 2018
- Authors: Moore, Sean D , Kirkman, Wayne , Peyper, Mellissa , Thackeray, Sean R , Marsberg, Tamryn , Albertyn, Sonnica , Hill, Martin P
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423729 , vital:72089 , xlink:href="https://doi.org/10.1093/jee/toy287"
- Description: The litchi moth, Cryptophlebia peltastica (Meyrick) (Lepidoptera: Tortricidae), is endemic to sub-Saharan Africa and certain Indian Ocean islands. It is an important pest of litchis and to a lesser extent macadamias. Litchis are exported to certain markets that consider C. peltastica as a phytosanitary pest. Consequently, an effective postharvest phytosanitary treatment is required. This study sought to develop a cold disinfestation treatment for this purpose. First, it was established that the fifth instar was the most cold-tolerant larval stage, as it was the only instar for which there was still some survival after 12 d at 1°C. It was then determined that cold treatment trials could be conducted in artificial diet, as there was no survival of fifth instar C. peltastica in litchis after only 9 d at 1°C, whereas it took 15 d at this temperature before no survival of fifth instar C. peltastica was recorded in artificial diet. Consequently, cold susceptibility of fifth instar C. peltastica and the most cold-tolerant larval stages (fourth and fifth instar) of false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), were compared in artificial diet. There was no survival of C. peltastica after 13 d at 1°C, whereas this was only so for T. leucotreta after 16 d. Consequently, it can be concluded that any cold treatment that has been proven effective against T. leucotreta would be as effective against C. peltastica. Finally, it was confirmed that the cold susceptibility of T. leucotreta in artificial diet did not overestimate the effect of cold on T. leucotreta larvae in litchis.
- Full Text:
- Date Issued: 2018
Integrating chemical control with sterile insect releases in an integrated pest management programme for Thaumatotibia leucotreta
- Nepgen, Eugene, Moore, Sean D, Hill, Martin P
- Authors: Nepgen, Eugene , Moore, Sean D , Hill, Martin P
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423770 , vital:72092 , xlink:href="https://doi.org/10.1111/jen.12487"
- Description: False codling moth Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is an important indigenous pest of citrus in southern Africa. Successful control is dependent upon integration of area-wide sterile insect releases and other suppression methods. The aim of this work was to test pyrethroid and organophosphate-based insecticides (tau-fluvalinate and chlorpyrifos) for their residual effect on mortality of released irradiated T. leucotreta male moths. Both of these insecticides were effective in killing irradiated T. leucotreta for 7 days after application on leaves, after which degradation of the active ingredient resulted in a marked reduction in efficacy after 14 days and rendering them harmless. Mortality was found to be similar for irradiated and non-irradiated male T. leucotreta after treatment. Consequently, even though these insecticides might have an effect on moths in the field, ratios of sterile:wild moths should not be altered. Supporting field data from six sites in the Sundays River Valley over a season of sterile insect releases showed the conventional chemical crop protection programme to be as effective as an integrated pest management programme in facilitating effective control of T. leucotreta through sterile insect releases. The study also confirmed that the ratios of sterile:wild male moths in the commercial citrus orchards were not affected by the application of insecticides. These findings confirm the high potential of sterile insect releases for control of T. leucotreta in citrus.
- Full Text:
- Date Issued: 2018
- Authors: Nepgen, Eugene , Moore, Sean D , Hill, Martin P
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/423770 , vital:72092 , xlink:href="https://doi.org/10.1111/jen.12487"
- Description: False codling moth Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) is an important indigenous pest of citrus in southern Africa. Successful control is dependent upon integration of area-wide sterile insect releases and other suppression methods. The aim of this work was to test pyrethroid and organophosphate-based insecticides (tau-fluvalinate and chlorpyrifos) for their residual effect on mortality of released irradiated T. leucotreta male moths. Both of these insecticides were effective in killing irradiated T. leucotreta for 7 days after application on leaves, after which degradation of the active ingredient resulted in a marked reduction in efficacy after 14 days and rendering them harmless. Mortality was found to be similar for irradiated and non-irradiated male T. leucotreta after treatment. Consequently, even though these insecticides might have an effect on moths in the field, ratios of sterile:wild moths should not be altered. Supporting field data from six sites in the Sundays River Valley over a season of sterile insect releases showed the conventional chemical crop protection programme to be as effective as an integrated pest management programme in facilitating effective control of T. leucotreta through sterile insect releases. The study also confirmed that the ratios of sterile:wild male moths in the commercial citrus orchards were not affected by the application of insecticides. These findings confirm the high potential of sterile insect releases for control of T. leucotreta in citrus.
- Full Text:
- Date Issued: 2018
Morphological, genetic and biological characterisation of a novel alphabaculovirus isolated from Cryptophlebia peltastica (Lepidoptera: Tortricidae)
- Marsberg, Tamryn, Jukes, Michael, Krejmer-Rabalska, Martyna, Rabalski, Lukasz, Knox, Caroline M, Moore, Sean D, Hill, Martin P, Szewczyk, Boguslaw
- Authors: Marsberg, Tamryn , Jukes, Michael , Krejmer-Rabalska, Martyna , Rabalski, Lukasz , Knox, Caroline M , Moore, Sean D , Hill, Martin P , Szewczyk, Boguslaw
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419330 , vital:71635 , xlink:href="https://doi.org/10.1016/j.jip.2018.08.006"
- Description: Cryptophlebia peltastica is an agricultural pest of litchis and macadamias in South Africa with phytosanitary status for certain markets. Current control methods rely on chemical, cultural and classical biological control. However, a microbial control option has not been developed. An Alphabaculovirus from C. peltastica was recovered from a laboratory reared colony and morphologically characterised by transmission electron microscopy (TEM). Analysis of occlusion bodies indicated a single NPV (SNPV) varying in size from 421 to 1263 nm. PCR amplification and sequencing of the polh gene region using universal primers followed by BLAST analysis revealed a 93% similarity to a partial polh gene sequence from Epinotia granitalis NPV. Further genetic characterisation involving single restriction endonuclease (REN) digestion of genomic DNA was carried out to generate profiles for comparison against other baculovirus species and potential new isolates of the same virus. The complete genome of the virus was sequenced, assembled and analysed for a more comprehensive genetic analysis. The genome was 115 728 base pairs (bp) in length with a GC content of 37.2%. A total of 126 open reading frames (ORFs) were identified with minimal overlap and no preference in orientation. Bioassays were used to determine the virulence of the NPV against C. peltastica. The NPV was virulent against C. peltastica with an LC50 value of 6.46 × 103 OBs/ml and an LC90 value of 2.46 × 105 OBs/ml, and time mortality ranging between 76.32 h and 93.49 h. This is the first study to describe the isolation and genetic characterisation of a novel SNPV from C. peltastica, which has potential for development into a biopesticide for the control of this pest in South Africa.
- Full Text:
- Date Issued: 2018
- Authors: Marsberg, Tamryn , Jukes, Michael , Krejmer-Rabalska, Martyna , Rabalski, Lukasz , Knox, Caroline M , Moore, Sean D , Hill, Martin P , Szewczyk, Boguslaw
- Date: 2018
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/419330 , vital:71635 , xlink:href="https://doi.org/10.1016/j.jip.2018.08.006"
- Description: Cryptophlebia peltastica is an agricultural pest of litchis and macadamias in South Africa with phytosanitary status for certain markets. Current control methods rely on chemical, cultural and classical biological control. However, a microbial control option has not been developed. An Alphabaculovirus from C. peltastica was recovered from a laboratory reared colony and morphologically characterised by transmission electron microscopy (TEM). Analysis of occlusion bodies indicated a single NPV (SNPV) varying in size from 421 to 1263 nm. PCR amplification and sequencing of the polh gene region using universal primers followed by BLAST analysis revealed a 93% similarity to a partial polh gene sequence from Epinotia granitalis NPV. Further genetic characterisation involving single restriction endonuclease (REN) digestion of genomic DNA was carried out to generate profiles for comparison against other baculovirus species and potential new isolates of the same virus. The complete genome of the virus was sequenced, assembled and analysed for a more comprehensive genetic analysis. The genome was 115 728 base pairs (bp) in length with a GC content of 37.2%. A total of 126 open reading frames (ORFs) were identified with minimal overlap and no preference in orientation. Bioassays were used to determine the virulence of the NPV against C. peltastica. The NPV was virulent against C. peltastica with an LC50 value of 6.46 × 103 OBs/ml and an LC90 value of 2.46 × 105 OBs/ml, and time mortality ranging between 76.32 h and 93.49 h. This is the first study to describe the isolation and genetic characterisation of a novel SNPV from C. peltastica, which has potential for development into a biopesticide for the control of this pest in South Africa.
- Full Text:
- Date Issued: 2018
- «
- ‹
- 1
- ›
- »