Application Of Plant Exogenous Growth Substance In Controlling Tomato Gray Mould And Interaction With Fungicides

In this study, 10 plant exogenous growth substances were employed to induce the adult tomatoes and tomato seedlings to enhance their own resistance to gray mould disease. The action of their own on the growth ofBotritis cinerea and the influence upon the occurrence of gray mould disease after being induced with them were studied and evaluated; 13 of different kinds of fungicides were evaluated both in vitro and in vivo, and the effective ones to Botritis cinerea were screened. The combinations of the fungicides and the inducers were applied to control the development of tomato gray mould disease, and the synergistic effects and extents of plant exogenous growth substance to different fungicides were made out. The primary studies on the mechanism of inducers inducing the tomato's resistance were also undertaken. The results could be summarized as follows:It indicated through the treatments of and the experiments inoculating tomato seedlings in vivo that some plant exogenous growth substance studied could induce the tomato seedlings to resist the occurrence of gray mould disease and reduce the incidence and grade of it in the appropriate day after being induced with the fitting concentration used. But effect of reducing the occurrence of tomato gray mould was different according as the different plant exogenous growth substance. The effect of PP333 was the best among them, whose effects all readied above 80% whenever the tomato seedlings were induced. The results in adult tomato with the treatment of plant exogenous growth substance in vivo showed that the resistance induced in adult tomato by most of them to gray mould disease was not effective enough. The effects of most plant exogenous growth substances were a little lower, however PP333 showed a satisfying effect.The action of plant exogenous growth substance on Botritis cinerea in vitro indicated that PP333and isoprothiolane could control it directly, but the others inhibited it infirmly. After the results in vivo and in vitro were analyzed synthetically, there was concluded that the strong inhibition to Botritis cinerea was the main factor that PP333 andisoprothiolane could control the tomato gray mould disease effectively; The light or the absence of inhibitory effect of other plant exogenous growth substances to Botritis cinerea was the main factor that they didn't control tomato gray mould disease steadily. And that indicated that it was not enough to control the disease effectively with just depending on the regulatory of the plant physiological states; the effective results could reach only through the incorporation with the fungicides.The control effects were invested in different days to the tomato seedling inoculated after being induced and showed that the disease indices of tomato gray mould increased gradually as well as the ones of CK. There were no instinctive changes in the control effects in different day, which showed that the resistance that tomato produced after being induced was mainly to constrain the invasion of Botritis cinerea, only prevent the extension of it on the small side.There had been produced the severe pesticides resistance of Botritis cinerea to the common fungicides in use such as carbendazim and phanatemethyl of benzimidazoles, whose control effect were not good. Propiconazole, tebuconazole and thiadimefon could control this disease in field in a way. The control effects of procymidone and mydobutanil were common.The joint effect that several plant exogenous growth substances incorporated with different fungicides indicated that ethephon and brassinolide mixed with most of fungicides tested individually showed addictive or synergistic activities; isoprothiolane (IPT) often exhibited addictive activities; however salicylic acid and a -nahthaleneacetic often often showed antagonist effects. Isoprothiolane and brassinolide could increase the control effect of carbendazim to tomato gray mould disease, which indicated the use of plant exogenous growth substances could postpone the resistance of Botritis cinerea...