Regulators of ethylene biosynthesis or activity as a tool for reducing susceptibility of host plant tissues to infection by Botrytis cinerea

Several compounds were tested for their ability to reduce development of grey mould on rose, tomato, pepper, eggplant, French bean andSenecio sp. Removal of ethylene from the atmosphere surrounding rose flowers, or leaves of tomato and pepper, by potassium permanganate, resulted in slower grey mould development. Inhibition of ethylene activity by 2,5-norbornadiene controlled disease on all crops but tomato. Carbon dioxide controlled grey mould on roses, but the potential for use of these agents is in doubt. Inhibitors of ethylene biosynthesis such as aminooxyacetic acid (AOA), cobalt ion, the uncoupler 2,4-dinitrophenol and the radical scavenger salicylic acid were differentially effective in controlling the disease in the various hosts. Fifty mM AOA reduced grey mould on rose flowers by up to 97% when flowers were partially aerated. AOA was not phytotoxic on the tested rose cvs Golden Times and Jaguar. Combinations of ethylene absorption, inhibition of ethylene activity and ethylene biosynthesis did not result in better control as compared with the disease reduction ability of the compounds alone, tested on the various hosts. Application of benzyladenine, which reduces the host responsiveness to ethylene, resulted in 39–99% grey mould reduction in rose flowers and in leaves of tomato andSenecio sp. but was not effective on pepper or eggplant. Manipulation of ethylene presence and of host plant susceptibility to grey mould is discussed.Contribution from The Agricultural Research Organization, Bet Dagan, Israel, No. 3270-E, 1991 series.