Entomopathogenic fungi for control of soil-borne life stages of false codling moth, Thaumatotibia leucotreta (Meyrick) (1912) (Lepidoptera: Tortricidae)
- Authors: Coombes, Candice Anne
- Date: 2013
- Subjects: Tortricidae , Lepidoptera , Cryptophlebia leucotreta , Insect pests -- Biological control -- South Africa -- Eastern Cape , Tortricidae -- Biological control -- South Africa -- Eastern Cape , Citrus -- Diseases and pests -- Biological control -- South Africa -- Eastern Cape , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5607 , http://hdl.handle.net/10962/d1002057 , Tortricidae , Lepidoptera , Cryptophlebia leucotreta , Insect pests -- Biological control -- South Africa -- Eastern Cape , Tortricidae -- Biological control -- South Africa -- Eastern Cape , Citrus -- Diseases and pests -- Biological control -- South Africa -- Eastern Cape , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Description: False codling moth (FCM), Thaumatotibia leucotreta is an extremely important pest of citrus in South Africa and with the shift away from the use of chemicals, alternate control options are needed. One avenue of control which has only recently been investigated against the soil-borne life stages of FCM is the use of entomopathogenic fungi (EPF). In 2009, 12 entomopathogenic fungal isolates collected from South African citrus orchards showed good control potential during laboratory conducted bioassays. The aim of this study was to further analyse the potential of these isolates through concentration-dose and exposure-time response bioassays. After initial re-screening, concentration-dose response and exposure-time response sandconidial bioassays, three isolates were identified as exhibiting the greatest control potential against FCM in soil, Metarhizium anisopliae var. anisopliae (G 11 3 L6 and FCM Ar 23 B3) and Beauveria bassiana (G Ar 17 B3). Percentage mycosis was found to be directly related to fungal concentration as well as the amount of time FCM 5th instar larvae were exposed to the fungal conidia. LC50 values for the three isolates were not greater than 1.92 x 10⁶ conidia.ml⁻ₑ and at the LC₅₀, FCM 5th instar larvae would need to be exposed to the fungus for a maximum of 13 days to ensure a high mortality level. These isolates along with two commercially available EPF products were subjected to field persistence trials whereby net bags filled with a mixture of autoclaved sand and formulated fungal product were buried in an Eastern Cape citrus orchard. The viability of each isolate was measured on a monthly basis for a period of six months. All isolates were capable of persisting in the soil for six months with the collected isolates persisting far better than the commercially used isolates. Two of the isolates, G 11 3 L6 and G Ar 17 B3, were subjected to small scale laboratory application trials. Two formulations were investigated at two concentrations. For each isolate, each formulation and each concentration, FCM 5th instar larvae were applied and allowed to burrow into the soil to pupate before fungal application or after fungal application. Contact between fungi and FCM host is essential as, in contrast to pre-larval treatments, percentage mortality in post-larval treatments was low for both formulations and both isolates. For isolate G Ar 17 B3, a conidial suspension applied as a spray at a concentration of 1 x 10⁷ conidia.ml⁻ₑ obtained the highest percentage mortality (80 %). For isolate G 11 3 L6 however, both formulations performed equally well at a high, 1 x10⁷ conidia.ml⁻ₑ concentration (conidial suspension: 60 %; granular: 65 %) The results obtained thus far are promising for the control of FCM in citrus, but if these EPFs are to successfully integrate into current FCM control practices more research, some of which is discussed, is essential
- Full Text:
- Date Issued: 2013
- Authors: Coombes, Candice Anne
- Date: 2013
- Subjects: Tortricidae , Lepidoptera , Cryptophlebia leucotreta , Insect pests -- Biological control -- South Africa -- Eastern Cape , Tortricidae -- Biological control -- South Africa -- Eastern Cape , Citrus -- Diseases and pests -- Biological control -- South Africa -- Eastern Cape , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5607 , http://hdl.handle.net/10962/d1002057 , Tortricidae , Lepidoptera , Cryptophlebia leucotreta , Insect pests -- Biological control -- South Africa -- Eastern Cape , Tortricidae -- Biological control -- South Africa -- Eastern Cape , Citrus -- Diseases and pests -- Biological control -- South Africa -- Eastern Cape , Entomopathogenic fungi , Fungi as biological pest control agents , Biological pest control agents
- Description: False codling moth (FCM), Thaumatotibia leucotreta is an extremely important pest of citrus in South Africa and with the shift away from the use of chemicals, alternate control options are needed. One avenue of control which has only recently been investigated against the soil-borne life stages of FCM is the use of entomopathogenic fungi (EPF). In 2009, 12 entomopathogenic fungal isolates collected from South African citrus orchards showed good control potential during laboratory conducted bioassays. The aim of this study was to further analyse the potential of these isolates through concentration-dose and exposure-time response bioassays. After initial re-screening, concentration-dose response and exposure-time response sandconidial bioassays, three isolates were identified as exhibiting the greatest control potential against FCM in soil, Metarhizium anisopliae var. anisopliae (G 11 3 L6 and FCM Ar 23 B3) and Beauveria bassiana (G Ar 17 B3). Percentage mycosis was found to be directly related to fungal concentration as well as the amount of time FCM 5th instar larvae were exposed to the fungal conidia. LC50 values for the three isolates were not greater than 1.92 x 10⁶ conidia.ml⁻ₑ and at the LC₅₀, FCM 5th instar larvae would need to be exposed to the fungus for a maximum of 13 days to ensure a high mortality level. These isolates along with two commercially available EPF products were subjected to field persistence trials whereby net bags filled with a mixture of autoclaved sand and formulated fungal product were buried in an Eastern Cape citrus orchard. The viability of each isolate was measured on a monthly basis for a period of six months. All isolates were capable of persisting in the soil for six months with the collected isolates persisting far better than the commercially used isolates. Two of the isolates, G 11 3 L6 and G Ar 17 B3, were subjected to small scale laboratory application trials. Two formulations were investigated at two concentrations. For each isolate, each formulation and each concentration, FCM 5th instar larvae were applied and allowed to burrow into the soil to pupate before fungal application or after fungal application. Contact between fungi and FCM host is essential as, in contrast to pre-larval treatments, percentage mortality in post-larval treatments was low for both formulations and both isolates. For isolate G Ar 17 B3, a conidial suspension applied as a spray at a concentration of 1 x 10⁷ conidia.ml⁻ₑ obtained the highest percentage mortality (80 %). For isolate G 11 3 L6 however, both formulations performed equally well at a high, 1 x10⁷ conidia.ml⁻ₑ concentration (conidial suspension: 60 %; granular: 65 %) The results obtained thus far are promising for the control of FCM in citrus, but if these EPFs are to successfully integrate into current FCM control practices more research, some of which is discussed, is essential
- Full Text:
- Date Issued: 2013
Geographic variation in the susceptibility of false colding Moth, Thaumatotibia Leucotreta, populations to a granulovirus (CrleGV-SA)
- Authors: Opoku-Debrah, John Kwadwo
- Date: 2008
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10586 , http://hdl.handle.net/10948/984 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Description: The false codling moth (FCM), Thaumatotibia (=Cryptophlebia) leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a serious pest of citrus and other crops in Sub-Saharan Africa. The introduction of the Cryptophlebia leucotreta granulovirus (CrleGV-SA) Cryptogran and Cryptex (biopesticides) has proven to be very effective in the control of FCM. However, markedly lower susceptibility of some codling moth (CM), Cydia pomonella (L.) populations to Cydia pomonella granulovirus (CpGV-M), another granulovirus product used in the control of CM’s in Europe have been reported. Genetic differences between FCM populations in South Africa have also been established. It is therefore possible that differences in the susceptibility of these geographically distinct FCM populations to CrleGV-SA might also exist. To investigate this phenomenon, a benchmark for pathogenecity was established. In continuation of previous work with Cryptogran against the 1st and 5th instar FCM larvae, dose-response relationships were established for all five larval instars of FCM. In surface dose-response bioassays, the LC50 values for the 2nd, 3rd and 4th instars were calculated to be 4.516 x 104, 1.662 x 105 and 2.205 x 106 occlusion bodies (OBs)/ml, respectively. The LC90 values for the 2nd, 3rd and 4th instars were calculated to be 4.287 x 106, 9.992 x 106 and 1.661 x 108 OBs/ml, respectively. Susceptibility to CrleGV-SA was found to decline with larval stage and increase with time of exposure. The protocol was used in guiding bioassays with field collected FCM larvae. Laboratory assays conducted with Cryptogran (at 1.661 x 108 OBs/ml) against field collected FCM larvae from Addo, Kirkwood, Citrusdal and Clanwilliam as well as a standard laboratory colony, showed a significant difference in pathogenecity in only one case. This significant difference was observed between 5th instars from the Addo colony and 5th instars from the other populations. Four geographically distinct FCM colonies from Addo, Citrusdal, Marble Hall and Nelspruit were also established. Since Cryptogran and Cryptex are always targeted against 1st instar FCM larvae in the field, further comparative laboratory assays were conducted with the Addo colony and an old laboratory colony. Cryptogran was significantly more pathogenic than Cryptex against both the Addo and the old colony. However, a high level of heterogeneity was observed in responses within each population.
- Full Text:
- Date Issued: 2008
- Authors: Opoku-Debrah, John Kwadwo
- Date: 2008
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10586 , http://hdl.handle.net/10948/984 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Description: The false codling moth (FCM), Thaumatotibia (=Cryptophlebia) leucotreta (Meyrick) (Lepidoptera: Tortricidae) is a serious pest of citrus and other crops in Sub-Saharan Africa. The introduction of the Cryptophlebia leucotreta granulovirus (CrleGV-SA) Cryptogran and Cryptex (biopesticides) has proven to be very effective in the control of FCM. However, markedly lower susceptibility of some codling moth (CM), Cydia pomonella (L.) populations to Cydia pomonella granulovirus (CpGV-M), another granulovirus product used in the control of CM’s in Europe have been reported. Genetic differences between FCM populations in South Africa have also been established. It is therefore possible that differences in the susceptibility of these geographically distinct FCM populations to CrleGV-SA might also exist. To investigate this phenomenon, a benchmark for pathogenecity was established. In continuation of previous work with Cryptogran against the 1st and 5th instar FCM larvae, dose-response relationships were established for all five larval instars of FCM. In surface dose-response bioassays, the LC50 values for the 2nd, 3rd and 4th instars were calculated to be 4.516 x 104, 1.662 x 105 and 2.205 x 106 occlusion bodies (OBs)/ml, respectively. The LC90 values for the 2nd, 3rd and 4th instars were calculated to be 4.287 x 106, 9.992 x 106 and 1.661 x 108 OBs/ml, respectively. Susceptibility to CrleGV-SA was found to decline with larval stage and increase with time of exposure. The protocol was used in guiding bioassays with field collected FCM larvae. Laboratory assays conducted with Cryptogran (at 1.661 x 108 OBs/ml) against field collected FCM larvae from Addo, Kirkwood, Citrusdal and Clanwilliam as well as a standard laboratory colony, showed a significant difference in pathogenecity in only one case. This significant difference was observed between 5th instars from the Addo colony and 5th instars from the other populations. Four geographically distinct FCM colonies from Addo, Citrusdal, Marble Hall and Nelspruit were also established. Since Cryptogran and Cryptex are always targeted against 1st instar FCM larvae in the field, further comparative laboratory assays were conducted with the Addo colony and an old laboratory colony. Cryptogran was significantly more pathogenic than Cryptex against both the Addo and the old colony. However, a high level of heterogeneity was observed in responses within each population.
- Full Text:
- Date Issued: 2008
Understanding and improving the residual efficacy of the cryptophlebia leucotreta granulovirus (Cryptogran)
- Authors: Kirkman, Wayne
- Date: 2008
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5794 , http://hdl.handle.net/10962/d1005482 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Description: False codling moth (FCM), Thaumatotibia (=Cryptophlebia) leucotreta (Meyr) (Lepidoptera: Tortricidae), is one of the most important pests on citrus. The Cryptophlebia leucotreta granulovirus (CrleGV) has been developed into a successful biological control agent, registered under the name Cryptogran, and is currently the preferred product for the control of FCM on citrus in South Africa. A prerequisite to the continued success of Cryptogran as a means of controlling false codling moth is to understand the factors affecting field persistence of the virus, and to find ways to improve it. The aim of this study was to gain a clearer understanding of the product and the abiotic and biotic factors affecting its persistence in the field, and to investigate methods to improve this persistence. The effect of UV-irradiation on the virus was determined, and various products were tested as UV protectants in laboratory bioassays. Lignin was the most effective additive, and was tested in several field trials, where it also enhanced the efficacy of Cryptogran. Laboratory trials indicated that Cryptogran is rainfast. Cryptogran applications early in the season had a longer period of residual activity than sprays applied closer to harvest. Daytime applications were less effective that evening sprays. Sprays applied coinciding with peaks in pheromone moth trap catches were more effective than those applied between peaks. Biotic factors influencing persistence were investigated. Residual efficacy was longer when treatments were applied to blocks than as single tree treatments. Attempts were made to quantify the effect of the navel end of a navel orange on the field persistence of Cryptogran. Cryptogran was shown to be compatible with many agricultural chemicals used on citrus. Economic thresholds and various cost-benefit analyses are discussed. A list of practical recommendations to growers was drawn up, and possibilities for future research are presented.
- Full Text:
- Date Issued: 2008
- Authors: Kirkman, Wayne
- Date: 2008
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5794 , http://hdl.handle.net/10962/d1005482 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , Citrus -- Diseases and pests
- Description: False codling moth (FCM), Thaumatotibia (=Cryptophlebia) leucotreta (Meyr) (Lepidoptera: Tortricidae), is one of the most important pests on citrus. The Cryptophlebia leucotreta granulovirus (CrleGV) has been developed into a successful biological control agent, registered under the name Cryptogran, and is currently the preferred product for the control of FCM on citrus in South Africa. A prerequisite to the continued success of Cryptogran as a means of controlling false codling moth is to understand the factors affecting field persistence of the virus, and to find ways to improve it. The aim of this study was to gain a clearer understanding of the product and the abiotic and biotic factors affecting its persistence in the field, and to investigate methods to improve this persistence. The effect of UV-irradiation on the virus was determined, and various products were tested as UV protectants in laboratory bioassays. Lignin was the most effective additive, and was tested in several field trials, where it also enhanced the efficacy of Cryptogran. Laboratory trials indicated that Cryptogran is rainfast. Cryptogran applications early in the season had a longer period of residual activity than sprays applied closer to harvest. Daytime applications were less effective that evening sprays. Sprays applied coinciding with peaks in pheromone moth trap catches were more effective than those applied between peaks. Biotic factors influencing persistence were investigated. Residual efficacy was longer when treatments were applied to blocks than as single tree treatments. Attempts were made to quantify the effect of the navel end of a navel orange on the field persistence of Cryptogran. Cryptogran was shown to be compatible with many agricultural chemicals used on citrus. Economic thresholds and various cost-benefit analyses are discussed. A list of practical recommendations to growers was drawn up, and possibilities for future research are presented.
- Full Text:
- Date Issued: 2008
The establishment of a virus free laboratory colony of Cryptophlebia leucotreta (False Codling Moth) and characterisation of Cryptophlebia leucotreta Granulovirus (CrleGV) genes
- Authors: Ludewig, Michael Hans
- Date: 2003
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , DNA viruses , Agricultural pests -- Biological control , Baculoviruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3957 , http://hdl.handle.net/10962/d1004016 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , DNA viruses , Agricultural pests -- Biological control , Baculoviruses
- Description: Cryptophlebia leucotreta is an economically important agricultural pest throughout Sub-Saharan Africa. CrleGV has been considered as an alternative to chemical control of this pest due to its host specificity and innocuous nature towards vertebrates. A CrleGV free laboratory colony of C. leucotreta would be useful for the isolation of genotypically pure strains of the CrleGV and for virulence comparisons between isolates. It is preferable to have a full characterisation of CrleGV prior to its registration and release into the environment as a biopesticide. A laboratory colony of C. leucotreta, set up at Rhodes University, containing a low level of infection indicated that CrleGV is vertically transmitted. To establish a virus free laboratory colony of C. leucotreta, a solution of 3.5% sodium hypochlorite and 1% Tween 20 was used to surface decontaminate C. leucotreta eggs for removal of transovum CrleGV from the laboratory colony. No apparent infection by CrleGV was induced by subjecting larvae to stress. PCR of DNA extracted from larvae using CTAB failed to detect virus in the laboratory colony. This detection protocol was able to detect down to 60 fg (480 genome copies of CrleGV). The possibility of low-level virus remaining in the colony requires monitoring of genotypic purity of virus manipulated in the colony. Sequencing of Bam HI/KpnI fragments produced a preliminary sequence of the granulin region of CrleGV. This preliminary sequence supports the trend that the gene organisation of the granulin region of the granuloviruses infecting the family Tortricidae is conserved.
- Full Text:
- Date Issued: 2003
- Authors: Ludewig, Michael Hans
- Date: 2003
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , DNA viruses , Agricultural pests -- Biological control , Baculoviruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:3957 , http://hdl.handle.net/10962/d1004016 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control , DNA viruses , Agricultural pests -- Biological control , Baculoviruses
- Description: Cryptophlebia leucotreta is an economically important agricultural pest throughout Sub-Saharan Africa. CrleGV has been considered as an alternative to chemical control of this pest due to its host specificity and innocuous nature towards vertebrates. A CrleGV free laboratory colony of C. leucotreta would be useful for the isolation of genotypically pure strains of the CrleGV and for virulence comparisons between isolates. It is preferable to have a full characterisation of CrleGV prior to its registration and release into the environment as a biopesticide. A laboratory colony of C. leucotreta, set up at Rhodes University, containing a low level of infection indicated that CrleGV is vertically transmitted. To establish a virus free laboratory colony of C. leucotreta, a solution of 3.5% sodium hypochlorite and 1% Tween 20 was used to surface decontaminate C. leucotreta eggs for removal of transovum CrleGV from the laboratory colony. No apparent infection by CrleGV was induced by subjecting larvae to stress. PCR of DNA extracted from larvae using CTAB failed to detect virus in the laboratory colony. This detection protocol was able to detect down to 60 fg (480 genome copies of CrleGV). The possibility of low-level virus remaining in the colony requires monitoring of genotypic purity of virus manipulated in the colony. Sequencing of Bam HI/KpnI fragments produced a preliminary sequence of the granulin region of CrleGV. This preliminary sequence supports the trend that the gene organisation of the granulin region of the granuloviruses infecting the family Tortricidae is conserved.
- Full Text:
- Date Issued: 2003
The characterisation of a South African isolate of Cryptophlebia leucotreta Granulovirus (CIGV)
- Authors: Singh, Shalene
- Date: 2002
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4067 , http://hdl.handle.net/10962/d1004929 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Description: The false codling moth (FCM), Cryptophlehia Leucatreta, causes widespread damage to economically important fruit crops throughout sub-Saharan Africa. Fruit are rendered unfit for consumption once they have been stung by FCM larvae. Larval infestation of fruit can lead to significant pre-harvest losses or post-harvest waste, posing a major problem to the citrus industry. Current control of the pest includes the use of chemical pesticides. The larval form of FCM is known to be infected by a granulovirus called Cryptophlebia leucotreta granulovirus (CIGV). Granuloviruses are highly specific against their hosts and are harmless to vertebrates, plants and the environment. The development of CIGV into a biological control agent would offer an attractive and safer alternative for the control of this pest. A full characterisation of CIGV is required prior to the virus being disseminated into the environment. In this project, the characteristics of CIGV will be examined. Viral DNA was extracted from infected larvae and the DNA analysed by restriction fragment length polymorphism (RFLP). Fragmentation profiles of the South African and Cape Verde (CV3) isolates of the virus were compared, revealing distinct differences between them. The size of the CIGV-SA genome was calculated to be 112 kbp, identical to the size of the CV3 isolate. Physical maps for five restriction enzymes were constructed for the CIGV-SA genome. The alignment of these maps with maps the CV3 isolate (for the same enzymes) further highlighted the differences between the isolates. The genetic engineering of granuloviruses could significantly improve the speed of kill of these viruses. Therefore essential genes like egt and granulin were isolated (by PCR) and their position located in the genome. Both genes were sequenced and their phylogeny with other granulin and egt genes investigated. Finally, tbe incidence of CIGV in natural populations of FCM larvae was investigated, by screening field-collected larvae for the presence of the virus. CIGV was successfully detected from dot blots of larval DNA using both radiolabelled and non-radiolabelled probes and by PCR. Trends regarding the incidence of CIGV in natural populations of larvae were also determined.
- Full Text:
- Date Issued: 2002
- Authors: Singh, Shalene
- Date: 2002
- Subjects: Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:4067 , http://hdl.handle.net/10962/d1004929 , Cryptophlebia leucotreta , Cryptophlebia leucotreta -- Control , Pests -- Biological control -- Africa , DNA viruses
- Description: The false codling moth (FCM), Cryptophlehia Leucatreta, causes widespread damage to economically important fruit crops throughout sub-Saharan Africa. Fruit are rendered unfit for consumption once they have been stung by FCM larvae. Larval infestation of fruit can lead to significant pre-harvest losses or post-harvest waste, posing a major problem to the citrus industry. Current control of the pest includes the use of chemical pesticides. The larval form of FCM is known to be infected by a granulovirus called Cryptophlebia leucotreta granulovirus (CIGV). Granuloviruses are highly specific against their hosts and are harmless to vertebrates, plants and the environment. The development of CIGV into a biological control agent would offer an attractive and safer alternative for the control of this pest. A full characterisation of CIGV is required prior to the virus being disseminated into the environment. In this project, the characteristics of CIGV will be examined. Viral DNA was extracted from infected larvae and the DNA analysed by restriction fragment length polymorphism (RFLP). Fragmentation profiles of the South African and Cape Verde (CV3) isolates of the virus were compared, revealing distinct differences between them. The size of the CIGV-SA genome was calculated to be 112 kbp, identical to the size of the CV3 isolate. Physical maps for five restriction enzymes were constructed for the CIGV-SA genome. The alignment of these maps with maps the CV3 isolate (for the same enzymes) further highlighted the differences between the isolates. The genetic engineering of granuloviruses could significantly improve the speed of kill of these viruses. Therefore essential genes like egt and granulin were isolated (by PCR) and their position located in the genome. Both genes were sequenced and their phylogeny with other granulin and egt genes investigated. Finally, tbe incidence of CIGV in natural populations of FCM larvae was investigated, by screening field-collected larvae for the presence of the virus. CIGV was successfully detected from dot blots of larval DNA using both radiolabelled and non-radiolabelled probes and by PCR. Trends regarding the incidence of CIGV in natural populations of larvae were also determined.
- Full Text:
- Date Issued: 2002
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