Biological Characteristics, Pathogenicity, and Sensitivity to Fungicides of Four Species of Lasiodiplodia on Avocado Fruits
2024
Yingying Chen | Xiaomei Lan | Rui He | Meng Wang | Yu Zhang | Ye Yang
This study focuses on four species of Lasiodiplodia (L. euphorbiaceicola, L. mahajangana, L. theobromae, and L. pseudotheobromae), which are associated with avocado stem end rot (SER) in Hainan, China. The factors affecting the growth of Lasiodiplodia, pathogenicity to avocado and other tropical fruits, and sensitivity to 12 fungicides, were tested. All Lasiodiplodia spp. isolates were grown between 10 °:C and 40 °:C, with optimal growth temperature ranging from 28 to 30 °:C: the lethal temperature ranged from 51 to 53 °:C for 10 min. Optimal growth pH ranged from 5 to 6. The most suitable medium was PDA, the preferred carbon sources were D&ndash:fructose and soluble starch, and the preferred nitrogen sources were yeast and beef extract. All Lasiodiplodia spp. isolates were highly pathogenic to avocado fruit. In addition, their pathogenicity to six tropical fruits (banana guava, mango, papaya, pitaya, and soursop) was evaluated, and the results reveal that all four species of Lasiodiplodia are able to infect these fruits to various degrees of severity. The pathogenicity of both L. theobromae and L. pseudotheobromae was the highest among all the species tested. All Lasiodiplodia spp. isolates were highly susceptible to the fungicides fludioxonil, carbendazim, thiophanate&ndash:methyl, tetramycin, iprodione, tebuconazole, prochloraz, and imazalil, which are good candidates for controlling avocado SER. The results of the present study provide important information on the biological characteristics of these four species of Lasiodiplodia and provide a basis for the management of SER in avocado.
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