Ecology and Epidemiology
Effects of Temperature, Moisture, and Stage of Inflorescence Development on Infection of Pineapple by Penicillium funiculosum and Fusarium moniliforme var. subglutinans. K. G. Rohrbach, Professor, Department of Plant Pathology, University of Hawaii, Honolulu 96822; G. Taniguchi, research assistant, Department of Plant Pathology, University of Hawaii, Honolulu 96822. Phytopathology 74:995-1000. Accepted for publication 20 March 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/Phyto-74-995.
Data on interfruitlet corking (IFC), leathery pocket (LP), and fruitlet core rot (FCR) induced by Penicillium funiculosum were collected from 36 tests from 1972 through 1978 and on FCR induced by Fusarium moniliforme var. subglutinans from 26 tests. Correlation coefficients were calculated for the incidence and severity of infected fruit versus temperature, rainfall, and leaf wetness during the first 15 weeks following the chemical forcing (time postforce) of flower induction. With natural infection by P. funiculosum, significant positive correlations occurred between hours per week at 16-
21 C and IFC, LP, and FCR during the first 5 weeks postforce. In contrast, with artificial inoculations, significant positive correlations occurred at 10-
15 weeks postforce. With infections by F. moniliforme var. subglutinans in both natural and artificial inoculations, significant positive correlations occurred for hours per week at 21-
27 C and FCR during flowering (10-
15 weeks postforce). Rainfall was more important for natural infections than for artificial inoculations with P. funiculosum. Significant positive correlations occurred with natural infections during 1-
5 weeks postforce and 10-
15 weeks postforce. No rainfall correlation patterns were noted for infections by F. moniliforme var. subglutinans. Under a controlled environment, maximum infections by P. funiculosum (as indicated by unopened flowers) and IFC, LP, and FCR fruit symptoms occurred at 22 C day/14 C night. When inflorescences at different stages of development were subjected to 22 C day/14 C night, maximum infections occurred in the 1.25 cm open heart stage and in the late cone to early flower stage. No infection correlation patterns were noted in inoculations with F. moniliforme var. subglutinans.
Additional keywords: Ananas comosus.