Studies On Selection Of Anti-TMV Pesticides And Synergized Action

Tobacco mosaic virus (TMV) is a nationwide-occurred tobacco disease and usually makes great loss. Scientists carried through vast researches on controlling TMV, and acquired some successes. However, it couldn't obtain the ideal controlling efficacy on TMV for the complicated conditions in the fields. In this paper, the good antivirusicide using in tobacco or the pesticide focused on other crops such as bilken, brassinolide, copper (II) acetate monohydrate(C₄H₆CuO₄), ningnanmycin, moroxydine hydrochloride(MH), ZnSO₄ and their mixtures were examined to test the control efficacy against TMV and the effect on tobacco growth, by the bioassay in greenhouse and systemic field trail. The main object of this research was just to develop and creat new antiviral pesticide for controlling tobacco virus diseases, consequently it could provide guidance to control tobacco mosaic virus diseases during tobacco production process.1 Control efficacy of two natural product agents against TMVThe greenhouse experiment results showed that the control efficacy of the plant growth regulator brassinolide against TMV was generally less than 60%. Whether trailing of pre-inoculation or post-inoculation, the concentration of 0.38mg/L had better effect. Therefore, it could regulate the growth of tobacco to control TMV. Ningnanmycin had some controlling effect on TMV and preservation better than cure. When mixed with brassinolide, the prevention effect was not obvious, but the cure effect was stronger.2 Comparison of Control Efficacy on Different Agents against TMV2.1 Comparison Studies on two natural product pesticides against TMVThe field results showed that brassinolide and ningnanmycin had good effect on TMV. At the previous period the control efficacy of ningnanmycin was higher, while that of brassinolide was higher at the later period, and the difference was obvious. For example, the control efficacy of ningnanmycin was 100%, higher than brassinolide when investigated on the 7^th day after the first spraying, While at the last investigation the control efficacy of brassinolide (68.35%) was higher than that of ningnanmycin (58.70%). And they could accelerate the tobacco growth obviously, especially brassinolide, which is a new plant growth regulator. At the last investigation, the efficient leaves and height of tobacco treated with brassinolide were 18.9 and 82.93 cm respectively, while those of ningnanmycin were 17.9 and 76.84 cm.2.2 Comparison of control efficacy on two inorganic pesticides against TMVThe average control efficacy of copper (II) acetate monohydrate was higher than ZnSO₄, was more than 80%, while that of ZnSO₄ was approximately 65%. The different index of tobacco such as the width, length, the number of efficient leaf, the height and the girth of tobacco showed that the effect of C₄H₆CuO₄ on tobacco growth was lower.2.3 Comparison of control efficacy on two chemical pesticides against TMVThe disease incidence and incidence index remained a low level when sprayed bilken- II and MH. The control efficacy of bilken- II was not obvious,while that of MH was better and remained good control effect, the average control efficacy was more than 50% and 70% or so, respectively. With spraying more times, the effect of these two pesticides was more obvious in accelerating the growth of tobacco, and was different at last.3 Control efficacy of mixture against TMV3.1 Control efficacy of ningnanmycin brassinolide mixture against TMVThe field results showed that the mixture of ningnanmycin and brassinolide had some effect on TMV, and could accelerate the tobacco growth. The control efficacy of the mixture (79.21%) was stronger than the single agent brassinolide (67.67%) and ningnanmycin (65.11%). The height of tobacco treated by mixture was higher than the single agent treatment, and the difference was obvious. That of mixture was 12.43% higher than that of ningnanmycin and 4.17% than brassinolide.3.2 Control efficacy of bilken-brassinolide mixture against TMVThe field results showed that the control efficacy of the mixture (lower than 70%) of bilken- II and brassinolide was lower than bilken- II and brassinolide at the previous period, while was higher at later period (higher than 70%). It could accelerate tobacco growth more obviously than the single agent. 3.3 Control efficacy of MH·Cu·Zn mixture against TMVThe disease incidence and incidence index of MH·Cu·Zn mixture was higher than that of C₄H₆CuO₄, and the velocity was lower compared with the other two agents. In the course of spraying, its control efficacy was more and more higher and was steady when sprayed over; the control efficacy of MH was lower, but that of C₄H₆CuO₄ and ZnSO₄. In a word, the control efficacy were all good. The effect of mixture on tobacco growth was more and more obvious. The leaf size, the number of efficient leaf and the height were greater than CK, The leaf size and the height were larger than MH, C₄H₆CuO₄ and ZnSO₄. While the number of efficient leaf and the girth were larger than MH.3.4 Control efficacy of ningnanmycin·MH·Cu mixture against TMVThe field results showed that ningnanmycin, MH, C₄H₆CuO₄ and their mixture all had well control efficacy on TMV. While the control efficacy of mixture (78.43%) was only inferior to C₄H₆CuO₄ (86.51%).3.5 Control efficacy of bilken·ningnanmycin mixture against TMVThe results showed that the control efficacy of bilken- II, ningnanmycin and the mixture were unstable in the course of spraying. The mixture accelerated the tobacco growth obviously at last and the five indexes all showed obvious accelerated tobacco growth. For instance, the height of tobacco treated by the mixture was 88.72 cm, while that of ningnanmycin and bilken was 76.84 cm and 71.36 cm, respectively.4 Integrated evaluation to single pesticides and mixtures against TMVThe evaluation of the bioassay and field treatment results from the control efficacy against TMV and the promotion to tobacco growth showed that brassinolide had good effect on TMV, but lower than C₄H₆CuO₄ 1225mg/L in the single pesticides, and brassinolide·ningnanmycin mixture 66.79mg/L was the best among all of the mixtures. In order to control TMV effectively and advance the growth of tobacco, it was suggested to use twice at seedling stage and to employ three times after transplanting, at the seedling renew knee high stage, resettling stage and vigorous growing period respectively.