Sensitivity of Penicillium digitatum and P. italicum to Postharvest Citrus Fungicides in California

Phytopathology - Tập 89 Số 9 - Trang 716-721 - 1999
Gerald J. Holmes1, J. W. Eckert
1E-mail address: E-mail Address: [email protected]

Tóm tắt

Penicillium digitatum isolates (326), collected in California citrus groves and packinghouses, were assayed qualitatively for their sensitivity to imazalil, thiabendazole, and o-phenylphenol. Eighteen typical triple-resistant isolates, acquired in each of 3 years (1988, 1990, and 1994), were assayed quantitatively for their sensitivity to each of the three fungicides. No significant differences were found in the mean sensitivity of the isolates collected in different years. However, the proportion of isolates that were resistant to all three fungicides increased from 43% in 1988 to 77% in 1990 and 74% in 1994. Imazalil-resistant biotypes of P. digitatum were isolated frequently in California packinghouses, while resistant P. italicum was rare. No fungicide-resistant biotypes of either species were collected from citrus groves. Wild-type P. italicum was slightly less sensitive than wild-type P. digitatum to all three fungicides. The concentration of imazalil producing 50% growth inhibition (EC50) was three times greater when the age of the P. digitatum assay inoculum was increased from 12 to 24 h. Activity of imazalil increased with pH of the assay medium in the range pH 5.1 to 5.9, reflecting the greater concentration of dissociated imazalil at the higher pH value.

Từ khóa


Tài liệu tham khảo

Albert, A. 1985. Some numerical assistance. Pages 641-657 in: Selective Toxicity, the Physico-Chemical Basis of Therapy. 7th ed. Chapman & Hall, New York.

10.1094/PD-73-0773

10.1016/0925-5214(92)90033-L

10.1094/PD-75-1098

Davé B., 1989, Proc. Fla. State Hortic. Soc., 102, 178

10.1016/0304-4165(78)90456-7

10.1007/BF01976357

10.1007/BF01998780

Díaz Borrás M. A., 1987, Agroquím. Tecnol. Aliment., 27, 439

Eckert, J. W. 1987. Penicillium digitatum biotypes with reduced sensitivity to imazalil. (Abstr.) Phytopathology 77:1728.

10.1094/PD-78-0971

Eckert, J. W., and Wild, B. L. 1983. Problems of fungicide resistance in Penicillium rot of citrus fruits. Pages 525-556 in: Pest Resistance to Pesticides. G. P. Georghiou and T. Saito. eds. Plenum Publishing Corp., New York.

10.1007/BF01976954

10.1016/0261-2194(86)90107-9

10.1007/BF01974286

Harding Jr., P. R., 1962, Plant Dis. Rep., 46, 100

Harding Jr., P. R., 1972, Plant Dis. Rep., 56, 256

Harding Jr., P. R., 1976, Plant Dis. Rep., 60, 643

10.1094/PD-79-1068

10.1094/Phyto-84-719

Kalamarakis A. E., 1987, Chem. Control Newsl., 8, 18

Kaplan H. J., 1979, Proc. Fla. State Hortic. Soc., 92, 37

10.1094/PD-71-1066

Kuramoto T., 1976, Plant Dis. Rep., 60, 168

10.1071/APP9930037

10.1139/m62-078

Rebellato L. H., 1984, Proc. Int. Soc. Citric., 1, 588

10.1016/0261-2194(93)90138-9

10.1007/BF03041427

Skylakakis, G. 1987. Changes in the composition of pathogen populations caused by resistance to fungicides. Pages 227-237 in: Populations of Plant Pathogens, Their Dynamics and Genetics. M. S. Wolfe and C. E. Caten, eds. Blackwell Science Publications, Palo Alto, CA.

10.1094/PDIS.1997.81.11.1299

van Gestel J., 1988, Citrus Congr., 3, 1511

10.1007/BF03041432

van Tuyl, J. M. 1977. Genetics of fungal resistance to systemic fungicides. Ph.D. thesis. Agricultural University, Wageningen, the Netherlands.

10.1080/01140671.1994.9513821

Thông tin
Thông tin xuất bản

Phytopathology

Tập 89 Số 9

716-721

Thông tin tác giả