Cacao sustainability: The case of cacao swollen-shoot virus co-infection.

The cacao swollen shoot virus disease (CSSVD) is among the most economically damaging diseases of cacao trees and accounts for almost 15-50% of harvest losses in Ghana. This virus is transmitted by several species of mealybugs (Pseudococcidae, Homoptera) when they feed on cacao plants. One of the mitigation strategies for CSSVD investigated at the Cocoa Research Institute of Ghana (CRIG) is the use of mild-strain cross-protection of cacao trees against the effects of severe strains.

Epidemiology and Diagnostics of Cacao Swollen Shoot Disease in Ghana: Past Research Achievements and Knowledge Gaps to Guide Future Research.

Cacao swollen shoot disease (CSSD) caused by complexes of cacao swollen shoot badnaviruses (family , genus ) remains highly prevalent and devastating in West Africa. The disease continues to impact substantially on cacao yield loss, cacao tree mortality, and decline in foreign exchange income from cacao bean sales. Currently, the disease is estimated to have a prevalence rate of over 30% in Ghana, as assessed in the ongoing third country-wide surveillance program.

Cacao Swollen Shoot Viruses in Ghana.

Cacao swollen shoot virus causes cacao swollen shoot disease of (cacao) plants. At least six cacao-infecting species-, (previously known as ), , , , and -are responsible for the swollen shoot disease of cacao in Ghana. Each of these species consists of a multiplicity of strains.

Field evaluation of the impact of cocoa swollen shoot virus disease infection on yield traits of different cocoa (Theobroma cacao L.) clones in Ghana.

Cocoa swollen shoot virus disease (CSSVD) is a major disease of cacao (Theobroma cacao L.) in Ghana and other West African countries that grow the crop. Attempts to develop resistant varieties since the discovery of the disease in 1936 have yielded little success.

Inconsistent PCR detection of Cacao swollen shoot virus (CSSV) is linked to the occurrence of different variants across the cocoa regions of Ghana.

Reliable diagnostic tools capable of detecting latent and asymptomatic infections are critically important to support the management of the cocoa swollen shoot virus disease (CSSVD) and also to complement research activities on screening for resistant cocoa varieties. Development of efficient polymerase chain reaction (PCR) assays sensitive for detection of CSSV infections has thus been a major research focus over the years. Advances in the full genome sequence information have resulted in the design of several Cacao swollen shoot virus (CSSV)-specific and degenerate primers.

Spatiotemporal Spread of Cacao Swollen Shoot Virus Severe Strain 1A in Mixed Hybrid Cacao Pre-inoculated With Mild Strain N1.

The spatiotemporal spread of cocoa swollen shoot virus disease (CSSVD), which is caused by cacao swollen shoot virus (CSSV) severe strain 1A in mixed hybrid cacao pre-inoculated with CSSV mild strain N1 (CSSV-N1), was investigated during a field experiment from 2006 to 2017, at the Cocoa Research Institute of Ghana. The development of disease epidemics has been described by the use of statistical modeling. Protecting all cacao plants with CSSV-N1 reduced the rate of CSSV-1A symptom appearance by 43% ( = 0.

Use of Immune Crops as Barrier in the Management of Cacao Swollen Shoot Virus Disease (CSSVD)-Long-Term Assessment.

A field trial was conducted at the Cocoa Research Institute of Ghana from 1992 to 2004 to investigate the prospects of using Cacao swollen shoot virus (CSSV)-immune crops as a barrier to prevent the spread of the virus from existing outbreaks into newly established cacao plantings. The treatments consisted of four crops-citrus (Citrus spp.), oil palm (Elaeis guineensis Jacq.

Appraisal of Cocoa swollen shoot virus (CSSV) Mild Isolates for Cross Protection of Cocoa Against Severe Strains in Ghana.

Two mild strains of Cocoa swollen shoot virus (CSSV), N1 and SS365B, were assessed for their capability to mitigate the devastating effects of CSSV in field trials at the Cocoa Research Institute of Ghana in comparison with noninoculated cocoa plants. Analysis of growth, mortality, and yield of cocoa trees inoculated with the mild strains over a period of two decades between 1996 and 2014 indicated that the cocoa plants inoculated with mild strains performed significantly (P < 0.05) better in the presence of the severe strains (CSSV 1A) than noninoculated cocoa, albeit degenerated over time.

Effect of Soil Moisture Management on the Development of Potato mop-top virus-Induced Tuber Necrosis.

Potato mop-top virus (PMTV), transmitted by Spongospora subterranea f. sp. subterranea, the causal agent of powdery scab in potato, has become one of the most important tuber necrosis viruses in the United States.

Sensitivity of Potato Cultivars to Potato mop-top virus-Induced Tuber Necrosis.

Potato (Solanum tuberosum) cultivars representing four market classes were assessed for sensitivity to Potato mop-top virus (PMTV)-induced tuber necrosis in three separate trials in a field in North Dakota known to be infested with PMTV. Reverse-transcription polymerase chain reaction confirmed the presence of PMTV in randomly selected samples. Results of tuber necrosis assessments conducted during storage demonstrated that sensitivity to PMTV-induced tuber necrosis among cultivars follows a continuum of tolerant to sensitive.