Detection and incidence of pineapple heart rot disease caused by Phytophthora nicotianae in commercial farms in Puerto Rico

Authors: Serrato Diaz, Luz; SIMBAÑA-CARRERA, LORENA - University Of Puerto Rico; VELEZ-NEGRON, YESENIA - University Of Puerto Rico; RIVERA-VARGAS, LYDIA - University Of Puerto Rico

Submitted to: Journal of Agriculture of the University of Puerto Rico
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2023
Publication Date: 8/8/2023
Citation: Serrato Diaz, L.M., Simbaña-Carrera, L., Velez-Negron, Y., Rivera-Vargas, L.I. 2023. Detection and incidence of pineapple heart rot disease caused by Phytophthora nicotianae in commercial farms in Puerto Rico. Journal of Agriculture of the University of Puerto Rico. 106(2):233-246. https://doi.org/10.46429/jaupr.v106i2.21155.
DOI: https://doi.org/10.46429/jaupr.v106i2.21155

Interpretive Summary: One of the most important diseases of pineapple in tropical countries is pineapple heart rot disease (PHRD) caused by Phytophthora spp. This disease is characterized by soft rot and water-soaked lesions, the young leaves stop growing and turn yellow and in severe cases plant mortality reaches up to 100%. In mature plants, the infection moves up through the peduncle rotting the fruit. During a one-year survey conducted from March of 2018 to 2019, symptoms of PHRD were observed in five commercial fields located at Guanica, Lajas, Manati and Santa Isabel, Puerto Rico. Diseased plant tissue was disinfested and plated on selective media for Phytophthora spp. Aerial photographs using a DJI Phantom 3 drone was used to corroborate disease incidence taken in the field. Eleven isolates of Phytophthora nicotianae were collected from pineapple fields in Puerto Rico and identified using morphology and DNA extractions. A total of 72 pineapple acres were evaluated from five commercial pineapple fields in Puerto Rico. Approximately twenty acres were infected by P. nicotianae with an average of PHRD disease incidence of 29.02%. The highest percentage of incidences were observed in fields located at Guanica, Lajas and Manati with 40%, 40% and 30%, respectively. Confirming and estimating the incidence of P. nicotianae as causal agent of PHRD is important because is the first step for developing specific control measures against this disease in pineapple fields in Puerto Rico.

Technical Abstract: Pineapple heart rot disease (PHRD) caused by Phytophthora spp. is one of the most important diseases of pineapple. This disease is characterized by soft rot and water-soaked lesions, in severe cases plant mortality reaches up to 100%. During a one-year survey conducted from March of 2018 to 2019, symptoms of PHRD were observed in five commercial fields located at Guanica, Lajas, Manati and Santa Isabel, Puerto Rico. Diseased plant tissue was surface disinfested and plated on PARPH-V8 selective media for Phytophthora spp. Aerial photographs using a DJI Phantom 3 drone was used to corroborate PHRD incidence taken in the field. Eleven isolates of Phytophthora nicotianae were collected from pineapple fields in Guanica, Lajas, Manatí and Santa Isabel and identified using morphology and phylogeny of sequences of the mitochondrial cytochrome oxidase subunit I region (COI). A total of 72 pineapple acres were evaluated from five commercial pineapple fields in Puerto Rico. Approximately twenty acres were infected by P. nicotianae with an average of PHRD disease incidence of 29.02%. The highest percentage of incidences were observed in fields located at Guanica, Lajas and Manati with 40%, 40% and 30%, respectively. Confirming and estimating the incidence of P. nicotianae as causal agent of PHRD is important because is the first step for developing specific control measures against this disease in pineapple fields in Puerto Rico.