Integration of Bological and Chemical Methods for the Control of Pepper Gray Mold Rot Under Commercial Greenhouse Conditions

  • Park, Seon-Hee (Department of Agricultural Biology, Gyeonsang National University, Chinju) ;
  • Bae, Dong-Won (Department of Agricultural Biology, Gyeonsang National University, Chinju) ;
  • Lee, Joon-Taek (Department of Agricultural Biology, Gyeonsang National University, Chinju) ;
  • Chung, Sung-Ok (Department of Agricultural Biology, Gyeonsang National University, Chinju) ;
  • Kim, Hee-Kyu (Department of Agricultural Biology, Gyeonsang National University, Chinju)
  • Published : 1999.06.01

Abstract

Integration of microbial antagonists with fungicides was tried to control the gray mold caused by Botrytis cinerea on pepper in greenhouse conditions and to reduce fungicide uses. All of the selected bacterial antagonists, Bacillus amyloliquefaciens BL3, Paenibacillus polymyxa BL4, and Pseudomonas putida Cha94, completely inhibited the conidial germination of B. cinerea until 30 days after treatment. However, bacterial colonization of pepper phylloplane was poor in BL4, while the other bacterial isolates and the fungal antagonist Trichoderma harzianum TM colonized well on the phylloplane, maintaining the population density of 104-105 cfu/g until 15 days after microbial treatments. Out of 13 kinds of selected fungicides used for gray mold diseases, polyoxin B and BKF 1995 showed the most discriminatory activity on the fungal growth between B. cinerea and TM. TM grew readily on the media containing those fungicides, while B. cinerea showed poor or no mycelial growth on them. The selected fungicides and antagonists alone reduced incidence of gray mold on pepper, showing disease indices of about 2.4 to 3.0, while its was increased up to 4.2 in the untreated control. Alternate treatments with the antagonists and 2-fold diluted fungicides inhibited the disease incidence as much as the antagonists or fungicides alone, and reduced the secondary inoculum more than the single treatments. This suggests that integration of antagonists and fungicides may be an efficient way to reduce fungicide sprays with reliable control efficacy of the disease. However, there was not much difference in the early and mid-term disease progress among the treatments and the untreated control, probably due to extremely favorable environmental conditions for the disease development in this experiment.

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