Chemical suppression of the symptoms of two virus diseases

Abstract

Carbendazim applied at the rate of z g per plant to the roots of tobacco (Nicotiana tabacum cv. White Burley) plants before infection with tobacco mosaic virus (TMV) caused very considerable reduction in the severity of disease symptoms in systemically infected leaves but did not affect their virus content. Leaves of untreated, infected plants had a greatly reduced chlorophyll content IOO days after infection whereas the chlorophyll content of leaves of infected plants treated with carbendazim was similar to that of normal uninfected leaves. Carbendazim had no effect on the infectivity of TMV in vitro or on the local lesion reaction of N . glutinosa plants when inoculated with TMV.Carbendazim was applied to lettuce cv. Cobham Green at a total rate of 0-1 g per plant before and after they were infected with beet western yellows virus and the plants were then grown on in the field. At harvest time (50 days after infection) almost all the treated virus-infected plants were of a normal green appearance, whereas the untreated controls were almost all very severely yellowed and unmarketable.

Applied Plant Virology

“…Tomlinson et al (1976) demonstrated that fungicides such as Benlate and Bavistin, which contain methyl benzimidazole-2-yl-carbamate (MBC or carbendazim), reduced the severity of mosaic symptoms caused by TMV in tobacco, and yellowing symptoms produced by beet western yellows virus in lettuce. Recently, however, some systemic fungicides have been shown to suppress virus symptoms when applied to diseased plants, without necessarily reducing the concentration of virus within the plant.…”

Plant growth regulators and virus infection: A critical review

“…Part of the effect was attributed to a reduced ability of the aphid vectors to colonise treated plants, but an effect on susceptibility of treated plants to virus was also possible . Methyl benzimidazol-2yl carbamate (MBC), the water decomposition product and fungitoxic principle of the benomyl fungicides (28), inhibited formation of visible symptoms of TMV on tobacco and beet western yellows virus (BWYV) in lettuce (143) . Other studies showed that the multiplication of TMV in tobacco was strongly inhibited (46), and that MBC treatment completely prevented the normal inhibition of plant growth resulting from TMV infection (47) .…”

“…In many cases juvenile tissues such as meristems are known to support little or no virus multiplication (29,129,131) . MBC was found to be ineffective against several other viruses (11, 143) .…”

Virus Content and Symptom Expression in Samsun Tobacco Treated with Kinetin and a Benzimidazole Derivative

“…This leaf-age-dependent effect may be a possible explanation for the discrepancies found in the literature in relation to the effects of kinetin and benzimidazole derivatives on systemic hosts (BAILISS, COCKER and CASSELS 1977, FRASER and WHENHAM 1978, TOMLINSON, FAITHFULL and WARD 1976. In earlier investigations we demonstrated the existence of a "cytokinin gradient" in tobacco plants (BALAZS, BARNA and KIRALY 1976b) and showed that exogenously applied cytokinins had different effects on leaves of different Ages.…”

“…1976a, BALAZS, BARNA and KIRALY 1976b, SZIRMAI 1964, KIRALY, EL HAMMADY andPOZSAR 1968), there are conflicting reports as regards the effects on symptoms and virus multiplication in the case of a systemic host (BAILISS, COCKER and CASSELS 1977, FRASER and WHENHAM 1978, TOMLINSON, FAITHFULL and WARD 1976. These contradictory results may due to the different hosts and viruses used in those experiments as well as to treatments carried out in different ways, including the time of treatment (whether before or after inoculation with the virus) (ALDWINCKLE 1975).…”