MICROBIOLOGICAL CONTROL OF BOTRYTIS CINEREA PERS. II. ANTAGONISM BY FUNGI AND ACTINOMYCETES

Abstract

Botrytis cinerea has been inhibited by pure cultures of many fungi and actinomycetes on lettuce extract agar and by these and by the mixed flora of soil suspensions on wounded detached lettuce leaves and on wounded leaves of living plants under conditions of high moisture and humidity. Control was exhibited in many cases at 4" C. though this was less marked than that at 15-25" C . Most fungal activity raised the pH to 7-8-8.4 but the use of buffered media showed that most species were antagonistic because of the production of antibiotic substances independently of the high pH. Prior inoculation with soil suspensions was necessary to obtain control cf B. cinerea on wounded leaves of living plants although such suspensions and several fungi had given control on simultaneous inoculation with B. cinerea on wounded detached leaves.Saprophytic antagonism is responsible for some of the natural control of B. cinerea in the field. The amount of available moisture, which in turn is affected by the relative position of the dead tissue on the plant as well as by climatic factors, greatly influences the establishment and growth of B. cinerea and the amount of microbiological antagonism likely to be exerted.Three-weekly applications of suspensions of Cephalosporkm sp., Fusarium jloccifmm and Phoma eupyrena failed to give a significant increase in the final survival of lettuce in the field. On the other hand, s-weekly applications of a dust containing tetrachloronitrobenzene gave a highly significant increase in survival, efficiency being greatly increased by the use of cloches.Earthing up induces early rotting of the petioles of ageing leaves and so probably prevents entry of Botrytis cinerea into the stem. Increased survival in hollows as compared with ridges is apparently due largely to this earthing up effect and possibly also to increased microbiological activity on dead tissue under the wetter conditions. B. cinerea can enter the soil by invasion down the root systems of attacked plants and can attack other root systems in contact with these. Furthermore it has been recovered from the soil over 6 weeks after the disappearance of infected plants from above ground, despite the antagonism shown to be exerted by soil organisms.Control of B. cinerea on Epilobium sp., Ranunculus repens, R.ji?amrnula and Lamium amplexicaule was obtained by prior inoculation of killed tissue with soil suspensions.The role of bacterial antagonism to Botrytis cinereu and the effect on Botrytis attack of the high pH frequently produced by saprophytic organisms on dead lettuce tissue has been discussed in the preceding paper (Newhook, 1951), where the general methods used have also been outlined. The literature on antagonism to B. cinerea has been reviewed by Wood (1951). Fungal antagonismDuring the 1946-7 and 1947-8 seasons over 200 isolations were made from fungi saprophytic on dead lettuce tissue in the field. 'The most frequent isolates were species of Fusarium, Phoma (amongst which Phoma eupyrena was very common), Cephalosporium, Cladosporium an...

Mechanisms involved in the biological control ofBotrytis cinerea incited diseases

“…The invasion of dead tissue by Bc was regarded by Newhook (1951) and Wood (1951) as a suitable process for inhibition of the pathogen by BCAs, since the substrate supports active saprophytic growth. They inoculated senescent lettuce leaves with antagonists such as Fusarium sp.…”

“…and Penicillium claviforma, isolated from the same crop, in order to prevent primary establishment of Bc. Saprophytic micro-organisms established naturally on dead lettuce tissue in the field gave a considerable degree of control of Bc (Newhook, 1951). Establishment of Cladosporium herbarum and Penicillium sp.…”

Purification and Identification of an Antifungal Protein from an Isolated Fungus with Antagonism to Colletotrichum gloeosporioides MC9

“…Many research reports that the aggressive isolate can be used as a biocontrol agent. Newhook (1951) and Wood (1951) research show that Fusarium inhibits the growth of Botrytis cinerea spp. and Penicillium claviforme, the antagonistic fungi from senescent lettuce leaves.…”